The wires were stuck in the 10/20 turns loop, so new hoops were cut.
The first one is a bit larger than the original one, and was wound with 5 turns. Resonant frequency got up to 2,1MHz, a little low for comfortably using it on the 160m band, so one turn was removed.
The 4 turn loop has self resonance on close to 2.5MHz, so I consider it acceptable for use on the 1.8MHz band.
It looks like an amplifier is needed to get better sensitivity.
The second hoop is intended for a single turn HF wideband loop, tests with transformer and amplifier should be done this year, as I have a cheap LNA, officially with a low cut off of 5MHz, but I suspect it will work fine on the 80m amateur band, too. A later version will probably be tested with a 1MHz cut off LNA, which is on the way from China.
The 10/20 turn loop will probably be tried out with even lower frequency reception (<100kHz).
2018-12-11
2018-12-10
LW/MW Loop : Self Resonance Measurements
20181209 :
I added an improvised electrostatic shield on the multiturn loop. Simply some kitchen aluminium foil wrapped around the loop (yes, with the proper gap) and connected to the coax shield with a test cord with alligator clips.
This is a simple test, and shows a considerable improvement of noise performance for the loop, both on the LW, and also on the MW band.
NDBs (navigation beacons) started showing up in the 250 - 500kHz band, some noise disappeared from long wave broadcast stations, and the noise level on MW is considerably lower, even with the antenna still indoors. I expect the noise level to reduce further when the loop is placed outdoors, 10 - 20m from all noisy houses.
A new MW evening propagation test is planned for tonight.
A mechanically improved shield will be made. I have some copper tape, sold as snail repellant, that will be wound around the loop and connected to the coax shield.
The loop design is now beginning to take shape, and when a cheap LNA capable on low frequencies arrives in some weeks. I will test this and, if necessary, build it into the connection box of the loop, along with a bias-tee arrangement.
20181210 :
The MiniVNA Pro2 arrived this morning, and some measurements of the loop were made. Initially I could not get the Bluetooth system to work, so I used the USB port, and got it working.
With 10 turns the self resonant frequency of the loop turned out to be around 900kHz, somewhat consistent with the performance I have seen.
The test with 20 turns lowered the self resonance to about 300kHz, I estimate that to be due to a combination of the 4-fold inductance and a considerably increased stray capacitance between windings. This is also consistent with the performance I experienced when initially testing with 10 and 20 turns.
The electrostatic shield made very little difference to the self resonance, so it will be re-instated in the final version of the loop.
Next experiment : Reduce the number of turns of the loop to 5 or 6, and see how much the self resonance increases.
I added an improvised electrostatic shield on the multiturn loop. Simply some kitchen aluminium foil wrapped around the loop (yes, with the proper gap) and connected to the coax shield with a test cord with alligator clips.
This is a simple test, and shows a considerable improvement of noise performance for the loop, both on the LW, and also on the MW band.
NDBs (navigation beacons) started showing up in the 250 - 500kHz band, some noise disappeared from long wave broadcast stations, and the noise level on MW is considerably lower, even with the antenna still indoors. I expect the noise level to reduce further when the loop is placed outdoors, 10 - 20m from all noisy houses.
A new MW evening propagation test is planned for tonight.
A mechanically improved shield will be made. I have some copper tape, sold as snail repellant, that will be wound around the loop and connected to the coax shield.
The loop design is now beginning to take shape, and when a cheap LNA capable on low frequencies arrives in some weeks. I will test this and, if necessary, build it into the connection box of the loop, along with a bias-tee arrangement.
20181210 :
The MiniVNA Pro2 arrived this morning, and some measurements of the loop were made. Initially I could not get the Bluetooth system to work, so I used the USB port, and got it working.
With 10 turns the self resonant frequency of the loop turned out to be around 900kHz, somewhat consistent with the performance I have seen.
The test with 20 turns lowered the self resonance to about 300kHz, I estimate that to be due to a combination of the 4-fold inductance and a considerably increased stray capacitance between windings. This is also consistent with the performance I experienced when initially testing with 10 and 20 turns.
The electrostatic shield made very little difference to the self resonance, so it will be re-instated in the final version of the loop.
Next experiment : Reduce the number of turns of the loop to 5 or 6, and see how much the self resonance increases.
2018-12-07
MW/LW Loop - transformed
I went to pick up RF transformers today. When inserted both noise and signals are attenuated, but it looks like the S/N is somewhat better.
The antenna was still located in the noise field of the shack, so I am not too surprised.
Time to connect a longer cable (still indoors) to test the loop a bit away from the shack with all its computers and SMPSs.
The weaker signals may be due to a different impedance match of the receiver through the transformer to the loop.
Moving the loop further away from the shack noise, about 3 - 5m, offers a considerable reduction of the noise level on LW. The RTTY station on 138kHz is now essentially noise free, i.e. I estimate it could easily be demodulated Signal is about S6, and noise is down to about S1. Another RTTY signal on around 133kHz is now clearly audible, and one on about 147kHz - previously drowning in the noise - is now quite strong. That was not the case with the loop closer to the shack noise.
MW is not so much better in that respect, so maybe too many turns still create too much stray capacitance. MW is better, but a considerable noise level still exists on large parts of the band, mostly a harsh hum with many overtones, probably from SMPSs.
Is it possible that I should use fewer turns to optimize the performance on MW? One more thing must be tested before testing the loop outside, and about 12-17m from the noisy shack - and 10 - 20m away from other potentially noisy houses.
Enough experimentation for now. More in the week end. Electrostatic shielding should be tested to see if the S/N can be further improved.
The antenna was still located in the noise field of the shack, so I am not too surprised.
Time to connect a longer cable (still indoors) to test the loop a bit away from the shack with all its computers and SMPSs.
The weaker signals may be due to a different impedance match of the receiver through the transformer to the loop.
Moving the loop further away from the shack noise, about 3 - 5m, offers a considerable reduction of the noise level on LW. The RTTY station on 138kHz is now essentially noise free, i.e. I estimate it could easily be demodulated Signal is about S6, and noise is down to about S1. Another RTTY signal on around 133kHz is now clearly audible, and one on about 147kHz - previously drowning in the noise - is now quite strong. That was not the case with the loop closer to the shack noise.
MW is not so much better in that respect, so maybe too many turns still create too much stray capacitance. MW is better, but a considerable noise level still exists on large parts of the band, mostly a harsh hum with many overtones, probably from SMPSs.
Is it possible that I should use fewer turns to optimize the performance on MW? One more thing must be tested before testing the loop outside, and about 12-17m from the noisy shack - and 10 - 20m away from other potentially noisy houses.
Enough experimentation for now. More in the week end. Electrostatic shielding should be tested to see if the S/N can be further improved.
2018-12-06
Adventures in Wideband Receive Antennas for LF and MF, Part 1.
After seeing posts on Youtube about people making simple wideband LF/MF/SW antennas I decided to go make my own. This is just the beginning, and a first test.
Two videos are the origin of my design, which is still under development.
One describes a simple single wire loop of about 3m circumference, connected to a cheap Chinese LNA, covering 1-2000MHz (price about $10). Sort of overkill in relation to the frequency range, but it is a very simple circuit to make, even with some not too tricky mechanical work.
The second video describes the use of a hula hoop to support the antenna. The loop described here has several turns of single strand wire pushed through the hoop, and is supposed to work up to about 10 - 12MHz.
I decided to make at least two loop antennas, one covering LF and MF, and another covering the HF bands. This is the beginning of the experimental LF/MF loop antenna.
I have purchased some cheap hula hoops on the toy store, priced less than $10.
I already had some cheap old fashioned speaker wire, so how to get several windings of that into the hoop ?
First step is cutting the hoop, so you have free ends of the plastic tube available. The hoop is quite tense, so the moment it is cut, it expands the radius, and you end up with a half circle of tubing. That is actually not too bad when you start pushing wire into the hoop. the speaker wire went nicely through to the other end of the tube.
Next step is a bit more tricky, but with a bit of thinking it was not difficult, but it was some work. I bent the tube with the wire through it, so the ends almost met, distance about 3cm, then used duct tape (surprise ! ;) ) to hold the ends together, then taped the end of the wire to the piece going through the hoop.
Now comes some hard finger work : Pushing/pukking the wire through the hoop, about 2cm at a time. After about half an hour or so I had 10 windings of 2-wire speaker cord.
[picture here]
If connected correctly in series this amounts to 20 turns of wire, but at first the test was done on 225kHz with 10 turns connected to a piece of RG58 cabe and my FRG-100 receiver - (in the mid-afternoon, so not many MW stations audible)
The signal was a steady S9+5 on the meter, so it was time to try connecting the windings in series, creating the 20 turn loop.
The 20 turns showed a weaker signal. Time to think a bit. I will assume that the problem with the 20 turns is a higher stray capacitance between the wires, lowering the self resonance of the loop.
Back to 10 turns it was, and voila ! The signal was back up again.
Do you see a weak point with this construction - not mechanically, but electrically ?
The multiturn loop is connected directly to the cable, creating (at least) two problems :
- the loop is originally balanced, the cable connection with a coax cable creates an imbalance, making the loop more sensitive to noise.
- the direct connection further has a galvanic connection to other wiring, giving the noise more opportunities to enter the loop.
Those two problems can be solved by inserting a RF transformer between the loop and the cable. The balance problem may not be completely eliminated, but, at least, it will be reduced. A local ham has offered me a 1:1 transformer that should be capable of handling the bands the antenna is meant for. Nice for initial testing.
I do have some low frequency toroids cores that I will test when I have the proper instrumentation. I suspect that it may be a good idea to use some up-transformation of the impedance/voltage from the loop.
I would like to be able to use this antenna for 136kHz, 472kHz and 1.8Mhz, and, of course for the MW broadcast band. It is possible, however, that I may have to insert some filtering in order to avoud overload of the receiver by strong MW signals. This will be tested, and added if necessary.
Here is a question that some may ask : Why make this solution when a properly constructed tuned frame multi turn antenna is better (no doubt it will, technically) ?
Well, The first point is simplicity of construction. I find it hard to imagine a more simple construction of a LF/MF antenna. Simply, do not make things more complex than necessary.
Second, I wanted an antenna capable of being used for more than one frequency, simultaneously.
Third, I wanted to go through the process of improving the system as the design allows.
In the near future there are, at least, the following improvements :
- adding the transformer, and possibly using an up transformer.
- test the possible improvement with an electrostatic shield.
- test if an amplifier is necessary in order to improve the S/N ratio.
- test if filters are necessary, because I will use this antenna in an environment with transmitters on higher frequencies than the design of this antenna, and the possibility of needing a filter eliminating strong MW broadcast transmitters.
- building the mechanical construction supporting the base and feed point of the antenna
I went to pick up RF transformers today. When inserted both noise and signals are attenuated, but it looks like the S/N is somewhat better.
The antenna is still located in the noise field of the shack, so I am not too surprised.
Time to connect a longer cable (still indoors) to test the loop a bit away from the shack with all its computers and SMPSs.
The weaker signals may be due to a different impedance match of the receiver through the transformer to the loop.
Moving the loop further away from the shack noise, about 3 - 5m, offers a considerable reduction of the noise level on LW. The RTTY station on 138kHz is now essentially noise free, i.e. I estimate it could easily be demodulated Signal is about S6, and noise is down to about S1. Another RTTY signal on around 133kHz is now clearly audible. That was not the case with the loop closer to the shack noise.
MW is not so much better in that respect, so maybe too many turns still create too much stray capacitance. MW is better, but a considerable noise level still exists on large parts of the band, mostly a harsh hum with many overtones, probably from SMPSs.
Is it possible that I should use fewer turns to optimize the performance on MW? One more thing must be tested before testing the loop outside, and about 12-17m from the noisy shack.
Enough experimentation for now. More in the week end. Electrostatic shielding should be tested to see if the S/N can be further improved.
Two videos are the origin of my design, which is still under development.
One describes a simple single wire loop of about 3m circumference, connected to a cheap Chinese LNA, covering 1-2000MHz (price about $10). Sort of overkill in relation to the frequency range, but it is a very simple circuit to make, even with some not too tricky mechanical work.
The second video describes the use of a hula hoop to support the antenna. The loop described here has several turns of single strand wire pushed through the hoop, and is supposed to work up to about 10 - 12MHz.
I decided to make at least two loop antennas, one covering LF and MF, and another covering the HF bands. This is the beginning of the experimental LF/MF loop antenna.
I have purchased some cheap hula hoops on the toy store, priced less than $10.
I already had some cheap old fashioned speaker wire, so how to get several windings of that into the hoop ?
First step is cutting the hoop, so you have free ends of the plastic tube available. The hoop is quite tense, so the moment it is cut, it expands the radius, and you end up with a half circle of tubing. That is actually not too bad when you start pushing wire into the hoop. the speaker wire went nicely through to the other end of the tube.
Next step is a bit more tricky, but with a bit of thinking it was not difficult, but it was some work. I bent the tube with the wire through it, so the ends almost met, distance about 3cm, then used duct tape (surprise ! ;) ) to hold the ends together, then taped the end of the wire to the piece going through the hoop.
Now comes some hard finger work : Pushing/pukking the wire through the hoop, about 2cm at a time. After about half an hour or so I had 10 windings of 2-wire speaker cord.
[picture here]
If connected correctly in series this amounts to 20 turns of wire, but at first the test was done on 225kHz with 10 turns connected to a piece of RG58 cabe and my FRG-100 receiver - (in the mid-afternoon, so not many MW stations audible)
The signal was a steady S9+5 on the meter, so it was time to try connecting the windings in series, creating the 20 turn loop.
The 20 turns showed a weaker signal. Time to think a bit. I will assume that the problem with the 20 turns is a higher stray capacitance between the wires, lowering the self resonance of the loop.
Back to 10 turns it was, and voila ! The signal was back up again.
Do you see a weak point with this construction - not mechanically, but electrically ?
The multiturn loop is connected directly to the cable, creating (at least) two problems :
- the loop is originally balanced, the cable connection with a coax cable creates an imbalance, making the loop more sensitive to noise.
- the direct connection further has a galvanic connection to other wiring, giving the noise more opportunities to enter the loop.
Those two problems can be solved by inserting a RF transformer between the loop and the cable. The balance problem may not be completely eliminated, but, at least, it will be reduced. A local ham has offered me a 1:1 transformer that should be capable of handling the bands the antenna is meant for. Nice for initial testing.
I do have some low frequency toroids cores that I will test when I have the proper instrumentation. I suspect that it may be a good idea to use some up-transformation of the impedance/voltage from the loop.
I would like to be able to use this antenna for 136kHz, 472kHz and 1.8Mhz, and, of course for the MW broadcast band. It is possible, however, that I may have to insert some filtering in order to avoud overload of the receiver by strong MW signals. This will be tested, and added if necessary.
Here is a question that some may ask : Why make this solution when a properly constructed tuned frame multi turn antenna is better (no doubt it will, technically) ?
Well, The first point is simplicity of construction. I find it hard to imagine a more simple construction of a LF/MF antenna. Simply, do not make things more complex than necessary.
Second, I wanted an antenna capable of being used for more than one frequency, simultaneously.
Third, I wanted to go through the process of improving the system as the design allows.
In the near future there are, at least, the following improvements :
- adding the transformer, and possibly using an up transformer.
- test the possible improvement with an electrostatic shield.
- test if an amplifier is necessary in order to improve the S/N ratio.
- test if filters are necessary, because I will use this antenna in an environment with transmitters on higher frequencies than the design of this antenna, and the possibility of needing a filter eliminating strong MW broadcast transmitters.
- building the mechanical construction supporting the base and feed point of the antenna
Until now the testing of the antenna has been inside the shack, which is a very noisy environment with computers, switching mode power supplies, mains noise etc, so some preliminary tests of the open construction outdoors may be necessary, especially to determine the need for an amplifier.
I look forward to do some more testing and finish the project, so expect a few more posts about this, and then phase II : HF active loop antenna.
I went to pick up RF transformers today. When inserted both noise and signals are attenuated, but it looks like the S/N is somewhat better.
The antenna is still located in the noise field of the shack, so I am not too surprised.
Time to connect a longer cable (still indoors) to test the loop a bit away from the shack with all its computers and SMPSs.
The weaker signals may be due to a different impedance match of the receiver through the transformer to the loop.
Moving the loop further away from the shack noise, about 3 - 5m, offers a considerable reduction of the noise level on LW. The RTTY station on 138kHz is now essentially noise free, i.e. I estimate it could easily be demodulated Signal is about S6, and noise is down to about S1. Another RTTY signal on around 133kHz is now clearly audible. That was not the case with the loop closer to the shack noise.
MW is not so much better in that respect, so maybe too many turns still create too much stray capacitance. MW is better, but a considerable noise level still exists on large parts of the band, mostly a harsh hum with many overtones, probably from SMPSs.
Is it possible that I should use fewer turns to optimize the performance on MW? One more thing must be tested before testing the loop outside, and about 12-17m from the noisy shack.
Enough experimentation for now. More in the week end. Electrostatic shielding should be tested to see if the S/N can be further improved.
2018-11-17
Tropo on 2m
Yesterday we had some tropo propagation on 2m.
Stations from most of Northern Europe were received, as well as a Southern France station in Provence.
In the evening the best signal was EA2XR in IN83ki (about 1750km), though I did not have enough power to work that one, and I just saw it after the fact, anyway.
The PSK Reporter map of stations received looks good.
Update 0855Z : 0739Z R5WM in KO72qi ( Kursk - about 1550km)
Stations from most of Northern Europe were received, as well as a Southern France station in Provence.
In the evening the best signal was EA2XR in IN83ki (about 1750km), though I did not have enough power to work that one, and I just saw it after the fact, anyway.
The PSK Reporter map of stations received looks good.
Update 0855Z : 0739Z R5WM in KO72qi ( Kursk - about 1550km)
2018-11-16
New Satellite With Amateur Radio Transponder Launched
The Es'hail 2 satellite has been launched and is going into geostationary orbit. This satellite has TV transponders, and something new for radio amateurs : a 2400MHz to 10GHz transponder in geostationary orbit.
The coverage should be all of Europe and Africa, to the East into India, and to the West a tiny bit of Brazil. I assume that some testing will be going on before the transponders go online, but this is an exciting time for radio amateurs interested in satellite communication.
For reception a 1m (3ft) dish with a PLL controlled LNB, as well as a receiver around 700MHz should be sufficient to hear the transponder on 10GHz, even if the frequency stability is probably not very good.
That would be my first step in amateur geostationary satellite communication.
Now I have to find a PLL-LNB.
2018-11-06
VP8 on a "Dead Band"
This afternoon provided a new DXCC for me, since I moved back to Denmark.
I was monitoring 10m FT8, and suddenly VP8LP (Falkland Islands)showed up on the screen, calling CQ. I did not even get the linear started
A single call from me was sufficient, and we exchanged -05/-09dB reports.
Now LW5DD is on ... starting the linear . LW5DD is long gone, but I called CQ for a while with no reply.
Earlier I could read ZS and 3B9 on 10m.
In any case, right now at the bottom of the solar cycle "10m is dead" .... No, not really.
I was monitoring 10m FT8, and suddenly VP8LP (Falkland Islands)showed up on the screen, calling CQ. I did not even get the linear started
A single call from me was sufficient, and we exchanged -05/-09dB reports.
Now LW5DD is on ... starting the linear . LW5DD is long gone, but I called CQ for a while with no reply.
Earlier I could read ZS and 3B9 on 10m.
In any case, right now at the bottom of the solar cycle "10m is dead" .... No, not really.
Update : 2m Horizontal
I went up to check the antenna system.
It looks like the cables to the preamplifier and between the preamp and antenna are fine, leaving a fault in the antenna.
I suspect corrosion in the antenna itself, and the fact that the construction of the Big Wheel antenna is not particularly water proof.
The "VSWR" at the radio shack shows just under 2:1, so I think that I will leave the antenna up for the winter, and just use the PA with reduced power into the system for the time being.
This is, of course, not ideal, but I am not going to take he system down right now, just before the winter with its super antenna weather (You know, rain, snow, ice, wind etc).
It is a compromise, I know, but better than having no antenna at all during the winter season. After all, I did hear English stations with this system last night, so it is functioning, after a fashion.
Come spring, a small beam with a rotator is in the planning.
It looks like the cables to the preamplifier and between the preamp and antenna are fine, leaving a fault in the antenna.
I suspect corrosion in the antenna itself, and the fact that the construction of the Big Wheel antenna is not particularly water proof.
The "VSWR" at the radio shack shows just under 2:1, so I think that I will leave the antenna up for the winter, and just use the PA with reduced power into the system for the time being.
This is, of course, not ideal, but I am not going to take he system down right now, just before the winter with its super antenna weather (You know, rain, snow, ice, wind etc).
It is a compromise, I know, but better than having no antenna at all during the winter season. After all, I did hear English stations with this system last night, so it is functioning, after a fashion.
Come spring, a small beam with a rotator is in the planning.
2018-11-05
Fault in my 2m Horizontal Antenna
It looks like I have a fault in my antenna system for the 2m Big Wheel antenna.
The PA suddenly started acting up when I used the HF Vox with FT8 on 2m. The antenna was tested at the radio end of the cable, and suddenly the SWR is around 2.5:1 over the whole band.
It is dark and rainy outside, so a check will have to wait until tomorrow. Climbing in on a wet ladder and in a wet tree is no fun.
Pity, because I was reading English stations on FT8 tonight, but no use ...
Update : Checked if the connector indoors was faulty, and used the opportunity to change it from a PL-259 to an N connector. I am expecting the new PA this week, so better be prepared.
Tomorrow I will check the outdoor part of the system, hoping it is easy to find and correct.
The PA suddenly started acting up when I used the HF Vox with FT8 on 2m. The antenna was tested at the radio end of the cable, and suddenly the SWR is around 2.5:1 over the whole band.
It is dark and rainy outside, so a check will have to wait until tomorrow. Climbing in on a wet ladder and in a wet tree is no fun.
Pity, because I was reading English stations on FT8 tonight, but no use ...
Update : Checked if the connector indoors was faulty, and used the opportunity to change it from a PL-259 to an N connector. I am expecting the new PA this week, so better be prepared.
Tomorrow I will check the outdoor part of the system, hoping it is easy to find and correct.
2018-11-01
VHF-UHF FM station at OZ9QV
For my main activity on 2m FM I use a pure 2m FM transceiver, no dual- or multi-band TRX there.
My antenna is the Diamond V-2000 capable of operating on 6m, 2m and 70cm.Until recently I used a cable running into my attic space, then extended down to the living room.
Having two extra junctions in the cable is bound to increase losses in the system, so I decided to lead the cable directly into the ground floor, eliminating the extra junctions. Just a single length of about 25m type 400 cable with a PL connector at the antenna, and N-connector in the living room.
Add a triplexer and 2m, 70cm and 6m can be connected to 3 different transceivers :
6m : My old IC-575 6/10m TRX for 6m. Only 10 W, but I do have a 100-150W PA lying around.
2m : A 70W 2m FM TRX.
70cm : My FT-8900 running on 2 frequencies on 70cm.
The results are encouraging . The RX, as well as TX performance of the system has improved audibly on 2m and 70cm. 6m was not tested. I estimate an improvement of 2-3 dB on he 2m part, and probably a bit more on the 70cm part.
Now I think of possible improvements.
Power capability :
The limit on power capabilities are with the antenna itself. The spec in the table at from Wimo's website says max 150W. The triplexer is somewhat better, specified for 800W PEP on 6m and 2m, and 500W on 70cm. I estimate from this that the FM capability for the triplexer is around 250/250/200W, so the limit is at the antenna.
Receiver sensitivity :
On 6m there is no problem at all. The antenna noise is clearly audible on the IC-575.
On 2m the loss in the cable/triplexer is probably low enough to be acceptable.
On 70cm, however, the cable/triplexer loss is probably around 3dB, reducing the RX sensitivity of the total system considerably. In any case more than 3dB, probably a deterioration of about 5dB when compared to an "ideal" system.
Conclusion :
There is room for improvement all around. on all 3 bands, though mostly on 70cm. This would mean moving the triplexer up into the mast, near the antenna. Oops, then we need more cables, but that is acceptable to me. The preamp(s) can then be mounted near the antenna, improving the system sensitivity (noise figure), especially on 70cm.Now, the antenna is located near my (big) shed, so it should be possible to mount linear amplifier(s) near the antenna, again with 70cm being the best improvement. For 6 and 2 the linears would probably be fine mounted in the shack.
I do have a set of German preamplifiers for 2m and 70cm, and even one for 6m, with noise figures around 0.6 - 1dB. This I consider sufficient for use with FM, for mostly local, or, as I call it, "local tropo" (distances within 250km from me). I know, with the right conditions this could be much more.
This is my idea for an optimized use of my antenna/linear/TRX combinations.
Further, I have a low placed antenna for 2m/70cm with a dual band TRX, for monitoring a local cross band repeater.
Additional :
I love to monitor several frequencies simultaneously, so, in addition to this, I would like to extend the receive side of the bands to include more receivers.
I see two options, either, a separate receive antenna with a preamp, and separate cable with power splitters going to different receivers, or, making switch boxes on each of the transceivers, each with a receive preamp and a power splitter for the receive signals.
For now, I monitor one frequency on 6m, 2 on 2m, and 3 on 70cm with the antenna system just described. Of course, when transmitting on one band, all other reception on that band is out of the question .... or is it? That is a story for another time.
All in all, receiving on 6 frequencies on 3 bands, and with TX capability on 3 bands, is not too bad for two antennas.
I have yet to improve the RX/TX capabilities as described, but that is a story (or more stories) for later. For now I am happy with the current improvement.
You may ask, why this is of interest . Well, I enjoy a local (or not so local) FM chat as much as many people, so there you have it.
My antenna is the Diamond V-2000 capable of operating on 6m, 2m and 70cm.Until recently I used a cable running into my attic space, then extended down to the living room.
Having two extra junctions in the cable is bound to increase losses in the system, so I decided to lead the cable directly into the ground floor, eliminating the extra junctions. Just a single length of about 25m type 400 cable with a PL connector at the antenna, and N-connector in the living room.
Add a triplexer and 2m, 70cm and 6m can be connected to 3 different transceivers :
6m : My old IC-575 6/10m TRX for 6m. Only 10 W, but I do have a 100-150W PA lying around.
2m : A 70W 2m FM TRX.
70cm : My FT-8900 running on 2 frequencies on 70cm.
The results are encouraging . The RX, as well as TX performance of the system has improved audibly on 2m and 70cm. 6m was not tested. I estimate an improvement of 2-3 dB on he 2m part, and probably a bit more on the 70cm part.
Now I think of possible improvements.
Power capability :
The limit on power capabilities are with the antenna itself. The spec in the table at from Wimo's website says max 150W. The triplexer is somewhat better, specified for 800W PEP on 6m and 2m, and 500W on 70cm. I estimate from this that the FM capability for the triplexer is around 250/250/200W, so the limit is at the antenna.
Receiver sensitivity :
On 6m there is no problem at all. The antenna noise is clearly audible on the IC-575.
On 2m the loss in the cable/triplexer is probably low enough to be acceptable.
On 70cm, however, the cable/triplexer loss is probably around 3dB, reducing the RX sensitivity of the total system considerably. In any case more than 3dB, probably a deterioration of about 5dB when compared to an "ideal" system.
Conclusion :
There is room for improvement all around. on all 3 bands, though mostly on 70cm. This would mean moving the triplexer up into the mast, near the antenna. Oops, then we need more cables, but that is acceptable to me. The preamp(s) can then be mounted near the antenna, improving the system sensitivity (noise figure), especially on 70cm.Now, the antenna is located near my (big) shed, so it should be possible to mount linear amplifier(s) near the antenna, again with 70cm being the best improvement. For 6 and 2 the linears would probably be fine mounted in the shack.
I do have a set of German preamplifiers for 2m and 70cm, and even one for 6m, with noise figures around 0.6 - 1dB. This I consider sufficient for use with FM, for mostly local, or, as I call it, "local tropo" (distances within 250km from me). I know, with the right conditions this could be much more.
This is my idea for an optimized use of my antenna/linear/TRX combinations.
Further, I have a low placed antenna for 2m/70cm with a dual band TRX, for monitoring a local cross band repeater.
Additional :
I love to monitor several frequencies simultaneously, so, in addition to this, I would like to extend the receive side of the bands to include more receivers.
I see two options, either, a separate receive antenna with a preamp, and separate cable with power splitters going to different receivers, or, making switch boxes on each of the transceivers, each with a receive preamp and a power splitter for the receive signals.
For now, I monitor one frequency on 6m, 2 on 2m, and 3 on 70cm with the antenna system just described. Of course, when transmitting on one band, all other reception on that band is out of the question .... or is it? That is a story for another time.
All in all, receiving on 6 frequencies on 3 bands, and with TX capability on 3 bands, is not too bad for two antennas.
I have yet to improve the RX/TX capabilities as described, but that is a story (or more stories) for later. For now I am happy with the current improvement.
You may ask, why this is of interest . Well, I enjoy a local (or not so local) FM chat as much as many people, so there you have it.
2018-10-27
A bit of DX - and FT8 on 60m.
Yesterday was a very radio active day for me.
I re-routed the cable for the 10 - 20m vertical, so I could use the PA with more power than through the diplexer. I went for about 400W.
Starting on 15m, BD7BS (China) and 9M2TO (Malaysia) with FT8, later the VK9XG DXpedition to Christmas Island on CW. Funny, I called and waited for a long time, and suddenly he called CQ again, and came back to me. Half a minute later he signed QRT.
17m FT8 yielded a few North American stations, a few Europeans, one South American and one Asian station. Quite OK, and the PA clearly improves chances.
In the evening I went for it on 60m FT8 with my special low band antenna. Lots of Europeans (no surprise there), in Asia UN7CBY and 4X1GA, and finally one North American, VE1YX, all with less than 50W (in Denmark we are allowed high power on 60m). Most of those 36 QSOs were replies to my CQs, all in less than 3 hours.
VE1YX I remember from my 10m/6m cross band operation days long ago. More about that in a later post.
The low band antenna does, due to its construction generate some RF in the shack, and after the operation I added a few more ferrite snap-ons to my cable. I will have to check the other bands, but on 60m I can now run the full 100W of the TRX on 60m.
Just over 50 QSOs in one day - and no contests - one of the highest counts for me in a single day.
I may have to try the 60m "trick" on another band some day (30m, 40m, 80m or 160m).
I re-routed the cable for the 10 - 20m vertical, so I could use the PA with more power than through the diplexer. I went for about 400W.
Starting on 15m, BD7BS (China) and 9M2TO (Malaysia) with FT8, later the VK9XG DXpedition to Christmas Island on CW. Funny, I called and waited for a long time, and suddenly he called CQ again, and came back to me. Half a minute later he signed QRT.
17m FT8 yielded a few North American stations, a few Europeans, one South American and one Asian station. Quite OK, and the PA clearly improves chances.
In the evening I went for it on 60m FT8 with my special low band antenna. Lots of Europeans (no surprise there), in Asia UN7CBY and 4X1GA, and finally one North American, VE1YX, all with less than 50W (in Denmark we are allowed high power on 60m). Most of those 36 QSOs were replies to my CQs, all in less than 3 hours.
VE1YX I remember from my 10m/6m cross band operation days long ago. More about that in a later post.
The low band antenna does, due to its construction generate some RF in the shack, and after the operation I added a few more ferrite snap-ons to my cable. I will have to check the other bands, but on 60m I can now run the full 100W of the TRX on 60m.
Just over 50 QSOs in one day - and no contests - one of the highest counts for me in a single day.
I may have to try the 60m "trick" on another band some day (30m, 40m, 80m or 160m).
2018-10-26
Nightly monitoring of 40m FT8
Last night I was monitoring the 40m FT8 frequency with my low hanging 5 band dipole.
This morning the PSK reporter showed spots from six continents, and lots of them.
In fact, all the six continents were reported in less than an hour around midnight local time. Also, some 80m work was done.
Activity from different areas can be seen clearly, there were even a lot of spots from New Zealand, about as far from me as can be on this earth.
During some of the monitoring session I tested my dipole against my home made low band antenna, and the findings were :
80m with dipole : The low hanging (feed point at about 4m above ground close to trees) was indeed quite good at reception S/N, but had a poor TX S/N.
80m with low band antenna : The low band antenna is quite noisy and has a poor RX S/N, but a considerable better S/N at TX.
40m with dipole : This worked considerably better at both transmit and receive, though not ideal, of course. Just looking at the RX reports from so many places tells me that. 40m was not tested with the low band antenna this time. More testing is required.
This morning TF5B was worked on 40m.
15m was worked a bit this morning, with a Chinese and a Malaysian station as resulting QSOs.
All in all not a bad night/morning at OZ9QV.
Winter time is low band time, so I expect to be a bit more active on 160 - 30m this winter. Ptobably mostly with FT8, but maybe a bit of QRP CW short distance work, too.
This morning the PSK reporter showed spots from six continents, and lots of them.
In fact, all the six continents were reported in less than an hour around midnight local time. Also, some 80m work was done.
Activity from different areas can be seen clearly, there were even a lot of spots from New Zealand, about as far from me as can be on this earth.
During some of the monitoring session I tested my dipole against my home made low band antenna, and the findings were :
80m with dipole : The low hanging (feed point at about 4m above ground close to trees) was indeed quite good at reception S/N, but had a poor TX S/N.
80m with low band antenna : The low band antenna is quite noisy and has a poor RX S/N, but a considerable better S/N at TX.
40m with dipole : This worked considerably better at both transmit and receive, though not ideal, of course. Just looking at the RX reports from so many places tells me that. 40m was not tested with the low band antenna this time. More testing is required.
This morning TF5B was worked on 40m.
15m was worked a bit this morning, with a Chinese and a Malaysian station as resulting QSOs.
All in all not a bad night/morning at OZ9QV.
Winter time is low band time, so I expect to be a bit more active on 160 - 30m this winter. Ptobably mostly with FT8, but maybe a bit of QRP CW short distance work, too.
2018-10-15
10m open to South America
The shack now has the capability of monitoring 13 frequencies simultaneously (except when transmitting).
Two more computers are set up for running WSJT-X (mostly FT8)
After setting up the computer for FT8 on HF, following the setup of the PA as previously described, 10m opened to Brazil, Argentina, Chile - and finally the Falkland Islands. PY5OD was worked.
The time of the year is the best for F2 propagation on the higher HF bands, and the solar cycle is at a minimum with a flux around 70 SFI. Even then 10m can open.
The old belief that 10m is closed during a solar minimum is clearly not correct. I know, FT8 makes thing possible that were previously impossible, but this gives new life to the 10m band, which has been my favourite HF band for decades.
Two more computers are set up for running WSJT-X (mostly FT8)
After setting up the computer for FT8 on HF, following the setup of the PA as previously described, 10m opened to Brazil, Argentina, Chile - and finally the Falkland Islands. PY5OD was worked.
The time of the year is the best for F2 propagation on the higher HF bands, and the solar cycle is at a minimum with a flux around 70 SFI. Even then 10m can open.
The old belief that 10m is closed during a solar minimum is clearly not correct. I know, FT8 makes thing possible that were previously impossible, but this gives new life to the 10m band, which has been my favourite HF band for decades.
2018-10-13
Using the PA for both HF and 6/4m transceivers.
I have a IC-7300 covering HF, 6m and 4m, and a IC-7600 covering HF and 50MHz. I would like simultaneous use through the PA of both transceivers to a R-6000 antenna and a 6m 1/2 wave antenna.
How to proceed? Here is my idea. Between the radios and the input of the PA I can use (lazy as I am) a commercial diplexer, like the CF-360 from Comet or the MX-62 from Diamond.
The problem with using those at the output of the amplifier is the limited power they can handle. 600W PEP or about 200W continuous. Not exactly fitting for the 1kW capability of the amp.
Looking a bit around on the net I found this : https://www.ka6wke.net/hf-vhf-diplexer , describing the use of a IC-7300 with an HF antenna and a 6m antenna with a home construction diplexer. There is a design that I could use, albeit with components capable of withstanding the higher power.
What about 4m ? At the moment of writing this, the power limit for 4m in Denmark is 25W, so the PA is not really necessary. If the limit goes up, I might think of a modification to the existing PA, or using a second transceiver for 4m and building a separate amplifier for 4m.
Next step is to find those components.
At the moment the amp is running low power, 200W, with a CF-360 at the output, connected to a vertical 1/2 wave 6m antenna, at the VHF port and the R-6000 at the HF port.
Now, here is the question some will ask :Why use a separate antenna for 6m when the R-6000 does 6m, too ? I have compared the two antennas, and I find that the 1/2 wave antenna for 6m performs far better than the R-6000 on that band. Further, since I do not intend to set up a HF beam, but at a later stage I do intend to have a small 6/4m capable of accepting the full power of the amp, so here we go !
I may design some high voltage capacitors , maybe made with PCBs, if I can not find some suitable for the 1kW filter I prefer to design for higher power than I intend to use, so I can avoid burnt components and/or equipment.
Oh, Boy ! Yet another project added to the pile ;)
How to proceed? Here is my idea. Between the radios and the input of the PA I can use (lazy as I am) a commercial diplexer, like the CF-360 from Comet or the MX-62 from Diamond.
The problem with using those at the output of the amplifier is the limited power they can handle. 600W PEP or about 200W continuous. Not exactly fitting for the 1kW capability of the amp.
Looking a bit around on the net I found this : https://www.ka6wke.net/hf-vhf-diplexer , describing the use of a IC-7300 with an HF antenna and a 6m antenna with a home construction diplexer. There is a design that I could use, albeit with components capable of withstanding the higher power.
What about 4m ? At the moment of writing this, the power limit for 4m in Denmark is 25W, so the PA is not really necessary. If the limit goes up, I might think of a modification to the existing PA, or using a second transceiver for 4m and building a separate amplifier for 4m.
Next step is to find those components.
At the moment the amp is running low power, 200W, with a CF-360 at the output, connected to a vertical 1/2 wave 6m antenna, at the VHF port and the R-6000 at the HF port.
Now, here is the question some will ask :Why use a separate antenna for 6m when the R-6000 does 6m, too ? I have compared the two antennas, and I find that the 1/2 wave antenna for 6m performs far better than the R-6000 on that band. Further, since I do not intend to set up a HF beam, but at a later stage I do intend to have a small 6/4m capable of accepting the full power of the amp, so here we go !
I may design some high voltage capacitors , maybe made with PCBs, if I can not find some suitable for the 1kW filter I prefer to design for higher power than I intend to use, so I can avoid burnt components and/or equipment.
Oh, Boy ! Yet another project added to the pile ;)
2018-10-11
More Shack Reorganisation
A bit more connected
Low band (160 - 30m) antenna connected to the 7600.
It looks like there is a loose connection in the connector/cable, and the cable is a bit short for proper reach. A repair or replacement of the connector is in order, but not today, as the soldering iron and other tools are not yet back in place.
The cable for the 6m/2m/70cm vertical is now shorter, with less connectors/junctions. As of now a single 25m run of CFD(LMR)400 with N-connector for the radio. This gave a clearly detectable improvement of the signals on 2m and 70cm. The cable was previously routed through an entry in the attic, as I started having the shack up there, and moved it down later. A cable is still routed that way, and can be used for some non-critical antenna, maybe as an antenna for a cross-band repeater (2,m/70cm) not to far from here.
The brilliant 2m tropo conditions of the last few days seems to have evaporated to a degree that I have difficulty working 2m DX, but may return, in different directions, in the week end. That is the prediction, at least.
Low band (160 - 30m) antenna connected to the 7600.
It looks like there is a loose connection in the connector/cable, and the cable is a bit short for proper reach. A repair or replacement of the connector is in order, but not today, as the soldering iron and other tools are not yet back in place.
The cable for the 6m/2m/70cm vertical is now shorter, with less connectors/junctions. As of now a single 25m run of CFD(LMR)400 with N-connector for the radio. This gave a clearly detectable improvement of the signals on 2m and 70cm. The cable was previously routed through an entry in the attic, as I started having the shack up there, and moved it down later. A cable is still routed that way, and can be used for some non-critical antenna, maybe as an antenna for a cross-band repeater (2,m/70cm) not to far from here.
The brilliant 2m tropo conditions of the last few days seems to have evaporated to a degree that I have difficulty working 2m DX, but may return, in different directions, in the week end. That is the prediction, at least.
2018-10-10
2m FT8 Up and Running
This morning I detected tropo (which was probably already there last night) on 2m FT8. Just heard the signals audible, and there was a lot.
Now was the time to get a computer connected, and set up. The tiny netbook was connected and showed good signals from the East and South-East.
Time to increase power from the about 8W. An old Tono MR 150W PA was connected, and measured about 80W output, providing about 40W to my Big Wheel omnidirectional antenna, running it quietly until the bigger one arrives in a few weeks.
I was a bit late to join the party, but I am now more ready than before to join again.
Best signals heard were UT2VR and R5WM at 1550 - 1600km. Not too bad for a small omnidirectional antenna.
It is not likely that I can get a much better antenna up before spring, so I will try to work a bit of tropo in the winter season, and see what I can do with that antenna and 40W, later about 300W at the antenna, running a bit of CW/SSB, but probably more FT8.
Update : Tropo again tonight. ODX with FT8 (2-way) UR3EE in KN88dc, 1840km. Not bad with a Big Wheel antenna.
Now was the time to get a computer connected, and set up. The tiny netbook was connected and showed good signals from the East and South-East.
Time to increase power from the about 8W. An old Tono MR 150W PA was connected, and measured about 80W output, providing about 40W to my Big Wheel omnidirectional antenna, running it quietly until the bigger one arrives in a few weeks.
I was a bit late to join the party, but I am now more ready than before to join again.
Best signals heard were UT2VR and R5WM at 1550 - 1600km. Not too bad for a small omnidirectional antenna.
It is not likely that I can get a much better antenna up before spring, so I will try to work a bit of tropo in the winter season, and see what I can do with that antenna and 40W, later about 300W at the antenna, running a bit of CW/SSB, but probably more FT8.
Update : Tropo again tonight. ODX with FT8 (2-way) UR3EE in KN88dc, 1840km. Not bad with a Big Wheel antenna.
2018-10-09
Rearranging the Shack Corner.
I recently started rearranging the corner of my living room holding my shack.
I needed a bit more space and a more convenient operation space for my transceivers and the new PA.
I have now started reconnecting radios/antennas/power supplies, and will get to the computers running the ham software soon. First things first ;).
Now, this time I am trying to arrange cables more neatly, so things take a little longer. Having enjoyed visitors does not speed up the process, but in any case, I will get there.
Most tricky part is monitors for the computers which take up a lot of the shelf space, vertically and horizontally, because they should also be readable from the operating position.
- and possibly, if the weather allows, a bit of antenna work should be tested as well.
I needed a bit more space and a more convenient operation space for my transceivers and the new PA.
I have now started reconnecting radios/antennas/power supplies, and will get to the computers running the ham software soon. First things first ;).
Now, this time I am trying to arrange cables more neatly, so things take a little longer. Having enjoyed visitors does not speed up the process, but in any case, I will get there.
Most tricky part is monitors for the computers which take up a lot of the shelf space, vertically and horizontally, because they should also be readable from the operating position.
- and possibly, if the weather allows, a bit of antenna work should be tested as well.
2018-09-30
Idea Box : Multiband QRSS receiver.
This idea is from some years ago, when the QRSS frequencies were (mostly) harmonically related.
Today I would probably use a SI5351 (3 output clock generator) as local oscillators for three receivers.
From 2009 :
This could be extended to 3 or 4 bands with some effort, but here is the basic idea :
I have some Crystals on 3500 , 7000 and 14000 kHz. This could make for an easy setup of a dual band grabber using a single local oscillator :
Here is the trick :
- make a single oscillator on 3500 kHz - use two buffers (possibly use the gates as buffers)- take one signal and use a direct conversion receiver circuit on 3500kHz, using the crystal filter of Joachim's QRSS receiver
- take the other signal and use the 3500 kHz LO signal for a receiver almost exactly as PA1GSJs receiver,
- making it a *simultaneous* dual band grabber receiver for :- 3500.800 - 3500.900 kHz- 7000.800 - 7000.900 kHz
Of course, the same idea could be used to make a 7000 / 14000 kHz dual band grabber receiver using 7000 and 14000 kHz Crystals.
There is even the option of making a doubler for the 3500 kHz signal, using this for extending the dual band grabber to a 3-band grabber for 3500/7000/14000 kHz.
Actually Joachim and I have been talking about the 3-band idea, but I have come to think that the 2-band idea is better in terms of simplicity of construction
Today I would probably use a SI5351 (3 output clock generator) as local oscillators for three receivers.
From 2009 :
This could be extended to 3 or 4 bands with some effort, but here is the basic idea :
I have some Crystals on 3500 , 7000 and 14000 kHz. This could make for an easy setup of a dual band grabber using a single local oscillator :
Here is the trick :
- make a single oscillator on 3500 kHz - use two buffers (possibly use the gates as buffers)- take one signal and use a direct conversion receiver circuit on 3500kHz, using the crystal filter of Joachim's QRSS receiver
- take the other signal and use the 3500 kHz LO signal for a receiver almost exactly as PA1GSJs receiver,
- making it a *simultaneous* dual band grabber receiver for :- 3500.800 - 3500.900 kHz- 7000.800 - 7000.900 kHz
Of course, the same idea could be used to make a 7000 / 14000 kHz dual band grabber receiver using 7000 and 14000 kHz Crystals.
There is even the option of making a doubler for the 3500 kHz signal, using this for extending the dual band grabber to a 3-band grabber for 3500/7000/14000 kHz.
Actually Joachim and I have been talking about the 3-band idea, but I have come to think that the 2-band idea is better in terms of simplicity of construction
2018-09-17
Very Simple QRSS Low Cost Grabber Idea.
I did not come up with the idea, but Radovan, OK1FCX on the QRSS mailing list did.
Here is the basics :
Use the cheap Pixie 40m TRX and a Raspberry Pi running QRSSPig, a program created by Martin, HB9FXX. This could be done within $50 for a complete grabber, uploading the grabber files to a free service like qsl.net, which is just for HAM radio.The crystal in the original Pixie is on 7023kHz, so a bit far from the frequency normally used for QRSS on approx. 7040kHz.
Now, OK1FCX used a 7030 crystal (the European QRP frequency on 40m), so got the audio frequency down to about 10kHz. It is possible to reduce that audio frequency to about 5kHz with a 7035 crystal available from Box73.de . However, I am in possession of a single crystal on 7038kHz, brining the audio frequency down to about 2kHz. It may be possible to adjust the crystal to fit in with the WSPR frequency on 40m, so the receiver could do double duty as a WSPR and QRSS RX.
Somewhere I should have an almost finished Warbler TRX, modified from the original 80m frequency to do 40m WSPR. If I can find it after my move, I should probably use that for a more permanent solution, but that is beside the point of the "cheap and dirty" QRSS setup. I should probably use one of my 7030 crystals as Radovan did.
In addition, the 40m Pixie could be used with crystals (that I have available) on 7000kHz to monitor the old (and maybe not used any more) QRSS frequency of about 7000.9kHz
I may have to ask on the QRSS mailing list, if more than one instance of QRSSPig can be run on a single Pi. How about a $50 dual frequency grabber ?
Here is the basics :
Use the cheap Pixie 40m TRX and a Raspberry Pi running QRSSPig, a program created by Martin, HB9FXX. This could be done within $50 for a complete grabber, uploading the grabber files to a free service like qsl.net, which is just for HAM radio.The crystal in the original Pixie is on 7023kHz, so a bit far from the frequency normally used for QRSS on approx. 7040kHz.
Now, OK1FCX used a 7030 crystal (the European QRP frequency on 40m), so got the audio frequency down to about 10kHz. It is possible to reduce that audio frequency to about 5kHz with a 7035 crystal available from Box73.de . However, I am in possession of a single crystal on 7038kHz, brining the audio frequency down to about 2kHz. It may be possible to adjust the crystal to fit in with the WSPR frequency on 40m, so the receiver could do double duty as a WSPR and QRSS RX.
Somewhere I should have an almost finished Warbler TRX, modified from the original 80m frequency to do 40m WSPR. If I can find it after my move, I should probably use that for a more permanent solution, but that is beside the point of the "cheap and dirty" QRSS setup. I should probably use one of my 7030 crystals as Radovan did.
In addition, the 40m Pixie could be used with crystals (that I have available) on 7000kHz to monitor the old (and maybe not used any more) QRSS frequency of about 7000.9kHz
I may have to ask on the QRSS mailing list, if more than one instance of QRSSPig can be run on a single Pi. How about a $50 dual frequency grabber ?
2018-09-14
Raspberry Pi SBCs and FT8.
Several years ago I purchased the second version of the Raspberry Pi (RPi) single board computer, a low powered PC costing about $35.-.
I did a few experiments with that one, and it has been in the drawer since I moved back to DK.
A few days ago a friend came here, and we pulled out the old RPi, and played a little, just with the command line interface.
The later V2 and 3 versions have much more power, having quad core processors, and the 3B+ having a 64 bit processor and a higher clock frequency than any of its predecessors.
I have a few RPi2s lying around unopened, and now I ordered (locally) two RPi3B+s.
As far as I know, the RPI2s can run the WSJT-X program, so one of the first experiments will be getting that program up and running on a RPi2, possibly running it from another screen (PC) via VNC. We shall see if the model 2 can support that, but I suspect it can.
Some time ago I purchased some single frequency QRP transceivers (superhet) running on USB on the JT65 frequencies, on 15, 20 and 40m. Since those differ from the from the JT65 frequencies by 2kHz on those bands I think it is possible to modify them by pulling the LO crystal. We shall see how that goes.The idea is mounting those small TRXs together with a couple of RPis, so full monitoring of all those bands simultaneously is possible without occupying a full HF TRX for just that purpose.
If the crystal pulling gets too tricky, e.g. insufficient frequency stability, I have some Si5351 boards with up to 3 frequency outputs between 8KHz and 160MHz.
Maybe getting some simple receivers up and running on other bands, releasing other TRXs for more general use.
We shall see, but first RPi setup and testing with one of the small TRXs. In the beginning just monitoring.
For the old 5 bands (10-15-20-40-80) I have a low hanging dipole, so a simple frequency multiplexer should not be too difficult to construct. I already purchased some toroid cores which should be good for winding the filter coils
I did a few experiments with that one, and it has been in the drawer since I moved back to DK.
A few days ago a friend came here, and we pulled out the old RPi, and played a little, just with the command line interface.
The later V2 and 3 versions have much more power, having quad core processors, and the 3B+ having a 64 bit processor and a higher clock frequency than any of its predecessors.
I have a few RPi2s lying around unopened, and now I ordered (locally) two RPi3B+s.
As far as I know, the RPI2s can run the WSJT-X program, so one of the first experiments will be getting that program up and running on a RPi2, possibly running it from another screen (PC) via VNC. We shall see if the model 2 can support that, but I suspect it can.
Some time ago I purchased some single frequency QRP transceivers (superhet) running on USB on the JT65 frequencies, on 15, 20 and 40m. Since those differ from the from the JT65 frequencies by 2kHz on those bands I think it is possible to modify them by pulling the LO crystal. We shall see how that goes.The idea is mounting those small TRXs together with a couple of RPis, so full monitoring of all those bands simultaneously is possible without occupying a full HF TRX for just that purpose.
If the crystal pulling gets too tricky, e.g. insufficient frequency stability, I have some Si5351 boards with up to 3 frequency outputs between 8KHz and 160MHz.
Maybe getting some simple receivers up and running on other bands, releasing other TRXs for more general use.
We shall see, but first RPi setup and testing with one of the small TRXs. In the beginning just monitoring.
For the old 5 bands (10-15-20-40-80) I have a low hanging dipole, so a simple frequency multiplexer should not be too difficult to construct. I already purchased some toroid cores which should be good for winding the filter coils
2018-09-10
Old Electronic Devices
After doing some computer work on low powered computers I decided to look into some older electronic equipment, like old mobile phones, tablet devices and MP3 players (iPods or other players).
Well a the old phones generally work, and can be charged, so the batteries are not quite dead.I will keep one or two for spares, and an older iPhone (32GB) can still be used as an MP3 player. The others are give-aways, as they are old and not very useful for Internet purposes.
Two of the old tablets remained on the boot screen, and I could not recover functions after a few hours. I discard them, and will probably give them to someone who wants to try getting them running. Probably a corrupted system, but I could not restore it, after a search on the Net.
Other old and very slow tablets will likely be given away, if someone wants to play with them, newer ones will probably be set up for different purposes, e.g. a picture viewer, or monitoring often visited websites, e.g. PSK Reporter or propagation monitoring sites, or DX cluster(s).
Well a the old phones generally work, and can be charged, so the batteries are not quite dead.I will keep one or two for spares, and an older iPhone (32GB) can still be used as an MP3 player. The others are give-aways, as they are old and not very useful for Internet purposes.
Two of the old tablets remained on the boot screen, and I could not recover functions after a few hours. I discard them, and will probably give them to someone who wants to try getting them running. Probably a corrupted system, but I could not restore it, after a search on the Net.
Other old and very slow tablets will likely be given away, if someone wants to play with them, newer ones will probably be set up for different purposes, e.g. a picture viewer, or monitoring often visited websites, e.g. PSK Reporter or propagation monitoring sites, or DX cluster(s).
2018-09-01
FT8 Propagation Monitoring.
I have always been interested in monitoring propagation on different bands.
Recently the digital mode FT8 has become very common on bands from 160m to 2m. Since my main interest is in VHF I have set up a few older computers, so I have continuous monitoring (barring the risk of thunderstorms) on 2, 4, 6 and 10m.
On 2, 4 and 6m I can immediately transmit (If I can find the correct mouse ;). On 10m I have continuous monitoring only, but a 5th machine can move around all HF bands and operate the transmitter on 10m as well.
Recently the digital mode FT8 has become very common on bands from 160m to 2m. Since my main interest is in VHF I have set up a few older computers, so I have continuous monitoring (barring the risk of thunderstorms) on 2, 4, 6 and 10m.
On 2, 4 and 6m I can immediately transmit (If I can find the correct mouse ;). On 10m I have continuous monitoring only, but a 5th machine can move around all HF bands and operate the transmitter on 10m as well.
2018-08-21
More Power to the Station
I finally gave in and purchased a PA for HF/6m.
I ended up with an Acom 1000, and it is mostly running 300W on 6m, mainly due to the power limit of my half wave vertical for 6m.
Now, for more power than that on 2m, what to do ?
I have seen some 50V 1kW modules for 2m on Ebay, as I do not intend to build from scratch.
The other option is a ready built PA, like the Gemini or the OM.
One takes some work, the other has a higher price.
Well, well, I might end up with the ready made one, after all.
I ended up with an Acom 1000, and it is mostly running 300W on 6m, mainly due to the power limit of my half wave vertical for 6m.
Now, for more power than that on 2m, what to do ?
I have seen some 50V 1kW modules for 2m on Ebay, as I do not intend to build from scratch.
The other option is a ready built PA, like the Gemini or the OM.
One takes some work, the other has a higher price.
Well, well, I might end up with the ready made one, after all.
2018-08-18
Spending and planning.
Lately I have been spending on eBay for components for my winter projects.
I want to build some accessories for my radios, e.g. a distributor for my memory keyer. The problem was that connecting radios in parallel at the keyer output sometimes results in one transceiver keying when another is switched off, so separate outputs for the different radios are necessary.
Another project is a band splitter for my 5 band dipole antenna, so 10-15-20-40 and 80m can be worked simultaneously, at least with low power, maybe up to 10 or 20W. Toroids for band pass filters are on the way.
Some 300 and 450 ohm feeder is already here, so some antenna experiments will be made within a few weeks/months. Only trouble is that due to chemo therapy (that has been stopped recently) I have side effects affecting the precision of using the hands and feet, so much care is needed when working with antennas. (Apparently also with typing, as many typing errors had to be corrected when I made this post).
Many other small projects are in the way.
A somewhat bigger one is getting my decades old 2m linear working. The tube has to be regenerated, and maybe the electrolytic capacitors have to be changed, as they may have dried up.
I want to build some accessories for my radios, e.g. a distributor for my memory keyer. The problem was that connecting radios in parallel at the keyer output sometimes results in one transceiver keying when another is switched off, so separate outputs for the different radios are necessary.
Another project is a band splitter for my 5 band dipole antenna, so 10-15-20-40 and 80m can be worked simultaneously, at least with low power, maybe up to 10 or 20W. Toroids for band pass filters are on the way.
Some 300 and 450 ohm feeder is already here, so some antenna experiments will be made within a few weeks/months. Only trouble is that due to chemo therapy (that has been stopped recently) I have side effects affecting the precision of using the hands and feet, so much care is needed when working with antennas. (Apparently also with typing, as many typing errors had to be corrected when I made this post).
Many other small projects are in the way.
A somewhat bigger one is getting my decades old 2m linear working. The tube has to be regenerated, and maybe the electrolytic capacitors have to be changed, as they may have dried up.
New country on 4m
This afternoon I worked a new country on 70MHz. E76C, Bosnia Hercegovina.
This is country #20 on this band, not bad for a simple vertical half wave antenna.
Later Iceland was on 6m. TF3ML and TF3JB have been in here for a fair long time, at least 1 1/2 hours. Both worked in a few calls on FT8.
This is country #20 on this band, not bad for a simple vertical half wave antenna.
Later Iceland was on 6m. TF3ML and TF3JB have been in here for a fair long time, at least 1 1/2 hours. Both worked in a few calls on FT8.
2018-08-03
New continent on 6m
In the past 3 years I have been running on 6m with just a half wave vertical.
This afternoon I had a pleasant surprise. I detected KP4EIT (Puerto Rico) with FT8, not a massive signal, but S/N of -6dB I tried a call, and after two tries he came back with a report of -18dB. New continent for me.
Not bad for a vertical on 6m, even if I run about 200W into the antenna (350W at the PA).
I see nearby stations decoding and calling other stations in that area, but no decodes here. But I am happy with country #53 in a 3 year period of very low solar activity, and a simple antenna.
I have detected stations from North and South America, and Asia, as well as, o course, Europe and Africa on FT8.
This afternoon I had a pleasant surprise. I detected KP4EIT (Puerto Rico) with FT8, not a massive signal, but S/N of -6dB I tried a call, and after two tries he came back with a report of -18dB. New continent for me.
Not bad for a vertical on 6m, even if I run about 200W into the antenna (350W at the PA).
I see nearby stations decoding and calling other stations in that area, but no decodes here. But I am happy with country #53 in a 3 year period of very low solar activity, and a simple antenna.
I have detected stations from North and South America, and Asia, as well as, o course, Europe and Africa on FT8.
2018-07-31
Update on the active antenna.
A while ago the active antenna stopped working. I suspect that it got too much HF from a nearby antenna.
A repair is needed, when the time is right.
I was using this antenna to monitor several frequencies from 137kHz to 70MHz, and I would like to be able to do this again. A way of monitoring up to 13cn is also in the thoughts.
Update later.
A repair is needed, when the time is right.
I was using this antenna to monitor several frequencies from 137kHz to 70MHz, and I would like to be able to do this again. A way of monitoring up to 13cn is also in the thoughts.
Update later.
Update
It has been a while since I last posted here, so here we go.
I have been undergoing a chemo treatment, so the activity level has been a bit lower than normal the past year or so (since I arrived back in Denmark 3 years ago).
Since last a bit of antennas have been set up. Essentially all verticals. Here is a quick overview for a few of the bands :
4m : Running my IC7100, sometimes with FM, sometimes with SSB/CW, and monitoring a lot of FT8. The last 3 years have yielded 19 countries in Europe only on 4m with such a simple setup.
6m : Mostly running with my IC 7300 and a half wave vertical, SSB/CW, and lately quite a bit of FT8. The last 3 years have yielded 52 countries in 3 continents, mostly with less than 100W(FT8 mostly 30W)
A few weeks ago a PA was added. Capable of about 1KW on 160 - 6m, it is now running at a very moderate 300W with all modes. The antenna cannot take any more. The improvement is noticeable with the higher power. Many stations previously unreachable are now possible.
10m : Now running with a IC7600, 100W or less. The antenna is ... surprise ... a half wave vertical. The last 3 years have got me 114 countries in 6 continents on that band. Not bad with the extremely low solar activity.
I have been undergoing a chemo treatment, so the activity level has been a bit lower than normal the past year or so (since I arrived back in Denmark 3 years ago).
Since last a bit of antennas have been set up. Essentially all verticals. Here is a quick overview for a few of the bands :
4m : Running my IC7100, sometimes with FM, sometimes with SSB/CW, and monitoring a lot of FT8. The last 3 years have yielded 19 countries in Europe only on 4m with such a simple setup.
6m : Mostly running with my IC 7300 and a half wave vertical, SSB/CW, and lately quite a bit of FT8. The last 3 years have yielded 52 countries in 3 continents, mostly with less than 100W(FT8 mostly 30W)
A few weeks ago a PA was added. Capable of about 1KW on 160 - 6m, it is now running at a very moderate 300W with all modes. The antenna cannot take any more. The improvement is noticeable with the higher power. Many stations previously unreachable are now possible.
10m : Now running with a IC7600, 100W or less. The antenna is ... surprise ... a half wave vertical. The last 3 years have got me 114 countries in 6 continents on that band. Not bad with the extremely low solar activity.
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