1296MHz etc. Portable. New Toy.

 I have got myself a new transceiver. For the microwave band I am now testing a new IC-905 and the 10GHz module (transverter).

This rig runs 10W on 144,432 and 1296MHz, and 2W on 2.4GHz and 5.7GHz, and 500mW on 10GHz.

It has 2 mast mounted modules, one transceiver for 144,432,1296MHz, 2.4GHz and 5.7GHz, the other converts the 2400MHz band to 10GHz. Everything is controlled fro a control module that resembles the IC-705, and it feeds 40V up to the modules via PoE (Power over Ethernet), and the rig has a common N-connector for 144,432 and 1296MHz, and separate SMA connectors for each of the higher bands.

The system has a built-in GPS for controlling the reference frequencies.

Time to do some tests, I started a few days ago. First, get it up on a tripod in the living room, and the tests could begin.

The very first tests was checking that the GPS system worked, and even indoors it would lock. I should be right on the frequency in the display.

I have not yet tested the 144 and 432MHz parts, but I set up a small 12 elements yagi in my living room, just 0.5m (about 2 feet) above the floor. To my surprise the OZ7IGY beacon located behind some hills about 20m higher was clearly audible. First successful test done!

I tried setting up a 2400MHz yagi (16 elements), and I was not surprised that I heard nothing from OZ7IGY. I could hear noises that I suspect came from the local wireless network. 

Using a PCB log-periodic antenna, exactly the same happened on 5760MHz. 

On 10GHz I set up a synthesizer generator in the house, and got a strong signal, using a PCB patch antenna array (16 patches in a 4x4 array). The transmit side was tested using my QO-100 receive setup, and worked nicely.

Today it was time to get out in the field. Temperature in the 15-20C range and some sunshine, it was a beautiful day to get started. I drove the system a few km from my home, just a bit up a hill, but not to the top (no driving permitted there). It took about 1/2 hour to get it up, and the test could begin, using the exact same antennas as in the indoor test.

The 1296MHz antenna was about 2.5m above ground and turned towards OZ7IGY. Signal was booming in, above S9. RX Success!

The 2400MHz antenna was very low above ground, about 70cm. The signal from OZ7IGY was a solid copy, though not very strong. RX Success

On 5760MHz the beacon was all but inaudible. I thought I could hear a signal tuning around the frequency, but I was not 100% sure, so I say no reception.

On 10GHz no reception (not surprising).

On 5.7 and 10GHz the cables used were some surplus semi-rigid cables with angled SMA connectors, so I suspect high losses, but the test had to be made. I am sure I could have gone to a different location with no hills in the way, and get reception, but I stayed because there was one more test to do.

I called on the local FM frequency (1297.500), and as I had announced my activity locally, there was immediate calls from 2 stations in the Copenhagen area and one in Sweden, just across the water. The SM7 station was 43km away and a solid S9, with a fairly unobstructed path.

One of the locals alerted a station in the other direction where there are some obstructing hills. Call made and good signals at 43km in the more obstructed path.

This was "first light" for my IC-905, and I am satisfied with the results. I can see many possible improvements to the system, so I have quite some work to do with the mechanical part of the portable system. Mainly better antennas for 2.4, 5.7 and 10GHz, and a better way to fix those antennas to the tripod. 

At today's test the 1.3 and 2.4GHz yagi antennas were mounted using gaffer tape, so there is already some hardware that I will need to go get, some holes to be drilled, so I can mount those antennas to the mast in a more secure way. As a first test, it was good enough, though.

1296MHz Improvement. Antenna Height.

 For a while I had my 1296MHz yagi mounted at a height of just 4m above ground. I could detect the DB0VC beacon in Kiel, about 200km distant, not constantly but every day I made the attempt.

On Easter Sunday I had a local ham help erecting a telescopic mast of 6m. This means that witg a little help from a friend it is possible to make antenna experiments for the higher bands. The rotatyor used is a small AR-500TV antenna rotator, and it works nicely with the small 1296MHz yagi.

The antenna is now 7m above ground (30m ASL), and I could detect a considerable improvement compared to the lower position, in some directions. In other directions there are still obstacles.

At the first test with 7m height 4 local stations were immediately heard, within about 10 minutes of starting operation on 1297.5MHz FM. This is encouraging. The furthest station was near Malmoe, Sweden, at a distance of about 30km, and while my yagi was horizontally polarized, and he used a vertical, we could get some fading signals. I suspect the fading, which came with very regular intervals, was due to some wind turbines along the path.

The beacon DB0VC is now heard a bit more regularly, and today I noticed something that I did not hear with the antenna at 4m. Several aircraft reflections were clearly audible, with the characteristic Doppler shift frequency change.

Today I also got a new station, running at a distance of about 20km, just running 4W, with the ADALM Pluto SDR and a front end with 4W output, running from a balcony with a home made 7 element yagi. Good signals, as we were both working with horizontal antennas.

For all this I used the IC9700. I also have a IC910 with a 1296MHz module.

Future developments:

Two more things are now needed to improve my system on 1296MHz:

- A good vertical antenna as high as I can get it. I intend to use the IC910 with this antenna, and a preamplifier near the antenna, just like with the yagi. Most likely the X-5000 from Diamond, used with a triplexer for multiband operation on 2m/70cm/23cm, with preamplifiers for every band.

- a power amplifier for each antenna/radio system. For the vertical/IC910 I intend to get a relay/sequencer up and running, so I can get about 25W at the antenna. For the yagi, I intend to get a maximum of about 75W at the antenna. I don't have the amplifier for that yet, but I will get one when I can.

Fault in the 23cm Antenna System.

There seems to be a fault in my temporary 23cm antenna system.

The signal disappears intermittently, and I suspect a fault in the connector for the cable bypassing the rotator. I have ordered better cables and N-connectors, so as soon as possible that cable should be replaced. Another option could be intermittent voltage to the preamplifier from the radio (IC9700), but the cable/connector fault is the most likely.

I will need to get some assistance from some local ham(s), as the antenna should be mounted about 2m higher, still in a temporary position. I cannot do that alone. The risk of damaging the antenna is too high.As the antenna is standing in my backyard and surrounded by houses and trees, every meter in height will help, so it will be interesting to see how much the signals will improve.

At a later stage I epxect to mount the antenna in 8-9m height. That is what I can do here. There will still be trees in the way in some directions, but it should be above houses in most directions.

Intermistic 1296MHz Yagi Setup.

The past few days I have worked getting a bit of activity going on 1296MHz.

The antenna is a Flexa Yagi model with 16 elements, for mounting behind the reflector.

The mast at the moment os just some military stackable pipes, and I could not handle more than 4m length alone, so that is the height of the antenna right now.

Results are varying. A station about 20km away could not hear my 5W at the antenna. He is in a poor direction, as the signal has to pass through my house, so maybe not too surprising.

We have had a bit of tropo propagation, so the beacon in Kiel, about 200-250km away is quite strong. In that direction the antenna points over free fields, and at the moment the signal from DB0VC is S9. During the day it was audible at all times. 

I do have a preamplifier near the antenna, so reception is quite decent.

At a later stage the antenna can be mounted at about 8m height, but the results are encouraging.

I did try to send a few CQs on 1296.200, but no replies. 

In the SE direction I can hear very strong radar signals, S-meter shows up to s9+30 in the peaks.

Next step will be getting the antenna higher up and see what happens. I will need assistance from some local hams, so it may take a little while.

A Bit of HF Activity.

 Today I put my first HF QSO of the year in the log. I didn't do much last year either, due to other commitments.

Today I made one of my forst QRP SSB QSOs in years. Some local stations had goe to Greenland and they have been quite active.

When they were reported on 18MHz I tried with just 5W SSB form my IC-705, even though the signal was not very strong. Much to my surprise OX7AKT came back to my call after one or two times, and we made the QSO. It is extra fun to do that with just 5W SSB and a half wave vertical.

More 8m Activity.

 Since last entry the solar activity dipped a bit and came back up. 

There were a few days without signals decoded, but a few came through.

PJ4MM Several days

ZS6OB and ZS3/V51PJ one day

The setup is still the IC703 and the 10m half wave vertical.

I am still running my 6m monitor, and I get European signals every day.

I need to expand the setup to 10m, and to more VHF (and UHF) bands.

Let the monitoring continue.

Update: ZF1EJ also came through today.

PJ4MM on 40MHz Again Today.

 Another good day for the 40MHz band.

One more time PJ4MM was coming through with up to 0dB S/N. 

It will be interesting to see how the 8m band monitoring will turn out this spring.

Monitor on 8m (40.680MHz)?

 I made my first test, listening on 40MHz. There is some experimental work going on on  40.680MHz with weak signal modes.

A local station with indoor antenna reported decoding PJ4MM, so I started testing

So I had my IC-703 connected to the 10m half wave antenna, and set the frequency. Pulse noise up to around S7. The noise blanker (NB) of the 703 seemed to make little difference. I tried to get the NB setting, and set it to the highest level. That reduced the noise, even if it is still not good. No S-meter reading.

Then PJ4MM came up on screen, starting with a S/N of -20dB, and for about 20minutes of the signal was there. Best S/N has been -7dB until now.

Not a bad beginning, given the severe pulse noise. DX heard on 8m.

Right now I am not going noise hunting, it is still winter time, and I have a cold, or the flu. In the spring I may try, and along with that, maybe try to make some phasing out of that noise. After all, it's only a single "channel" I need to cover. 

10GHz Transverter, Continued.

 In the autumn/fall last year I was out making a receive test of a 10GHz transverter briefly described a few days ago in the previous post. 

When I should have had a signal from the OZ7IGY beacon about 25km away, there was ... nothing.

I started the fault finding with a measurement of the LO module, and it did look pretty good. So Now the down converter should be tested.

I located a signal generator (low cost Chinese circuit with the ADF 5351 synthesizer. As the signal generator has a fixed output, I made a small loop for 10GHz, soldered to a low cost (chassis) SMA connector. Measure on the spectrum analyzer (with built-in frequency counter the signal generator seemed to stay within a few 100 Hz, with a fixed offset of about 10kHz. Good enough for a first test.

Power up the transverter with 12.5V, the IF connected to a Malahit DSP2 SDR set to 144MHz, and let the system warm up a bit. The 12.5V was about what the battery delivered at the test. 
It sounded absolutely dirty, with some irregular jumps in frequency.

Where was the instability? I tried connecting the FT-290 and it was the same. Apparently I could eliminat the possibilty of the Malahit going faulty. Now remains the LO of the transverter or the signal generator.

Next test was, let us see what happens if the supply voltage is increased.

Bingo. at 13.5V the LO apparently jumped to the correct frequency (well, about 3kHz low) and stayed there, the tone sounds good, all the dirt gone from the audio, and the sensitivity looked much better. You may laugh, I don't mind, because I foind the fault.

Connecting back to the Malahit SDR, and it looked good.

The Chinese signal generator, though has a rather noise output. Good enough to test the system, but the phase noise is atrocious, only about 10-20dB below the carrier. I heard that a ham not too far away has made some modifications, and I will look into that.

So what to do when I do go out into the field? I need 13.5V and the battery delivers only 12.5V. Too low for a good function.

I think I will try first with a different battery and a DC/DC converter. I know that the DC needs extra filtering, but it should be usable for the first field tests. Next step: check the TX function.

Fault Finding in an Old 10GHz Transverter.

In the autumn I made a first test of a home-made 10GHz transverter I got my hands on, and started testing.

The initial test was a simple connection to an older FT-290 transceiver, and going out to spme place a bit higher than where my house is located.

I was listening for the beacon OZ7IGY at a distance of about 25km. Nothing in the garden. If I placed an satellite TV LNB about 4m above ground I could hear the beacon, very weak, because it is behind some hills about 30m higher than where I am.

I tried to go to a place somewhat higher with the FT-290/transverter setup on a tripod, and tested. Absolutely nothing heard. tuning about 30kHz to either side of the beacon frequency.

So now I got started fault finding.

The first suspicion after talking to a local ham was the 2556MHz local oscillator module. Testing on a spectrum analyzer showed a nice signal with an offset of less than 600Hz. Not bad, this would give an offset of less than 3kHz. The output (to the Qualcomm up/down conversion module) is close to 5dBm, so that looks quite good. I can safely say that the LO module works nicely.

Now more tests are necessary.

 I do need a small 10GHz signal source, and I have thought of using one of the following:

- a low power (0.5W) 70cm FM transceiver with an attenuator and a single diode as multiplier

- a synthesizer PCB with a AD 4350 or 4351 chip, just using the 3rd harmonic. 

At least I can test those with the spectrum analyzer, so I know if there is a strong enough 10GHz signal.

I think the simplest of the two is the attenuator/diode multiplier, so I think I should start there.

A Bit of New Stuff, Arrived From China in December and January.

 I have ordered a few things from Ali Express recently, Some of this arrived in December last year, and this year until now.

Some of it still needs to be tested, but here are a few things that may be of interest.

Some time ago I got a collection of used 18650 Lithium Ion cells, so now I got myself a capacity tester. This needs to be tested.

I am slowly starting doing some experiments on the microwave bands, so I got myself a log-periodic antenna covering 800MHz - 6GHz, covering the amateur bands 1296, 2400,3400 and 5760MHz. Intended use is mainly for antenna testing, but it can also be used to feed a parabolic dish.

I am beginning to dismantle some older electronic equipment for (some) parts, so I got myself a desolder station.

A couple of LNAs claimed to cover 10MHz to 6GHz. Should be tested.

A Malahit SDR receiver, self contained with LCD screen and built-in speaker. A quick test shows an OK receiver. Nothing spectacular, officially covering 10kHz - 380MHz and 404 - 2000MHz, with spectrum display (max. 192kHz wide) Nice little receiver, can be useful for many tests, especially with portable equipment, but also converters and transverters (receive part only).

There is more, but those are the more interesting things for me.

Monitoring on 10m. Updated.

I got  a bit of space on the lab desk by now. Still much more tidying needed.

For now, part of my monitoring system for 10m consists of a half wave antenna, connected to my modified IC-703 with a loop-back for the receiver signal.

The receive signal is running through a power splitter, so part og the signal goes back to the receiver section of the '703 and two outputs go to other receivers. Two is not quite enough, as I want to monitor several frequencies around the 10m band. Some amplified power splitter is needed.

The frequencies I want to monitor on 10m are, at least:

- 28.200 (International Beacon Project) (with audio)

- 28.074 (FT8 frequency)

- 29.600 (FM calling frequency)

- 27.555 (Used by CBers as a calling frequency. Excellent propagation indicator for 10m)

- 28.126??? (WSPR and QRSS frequencies)

I have a couple of "transistor radio" portable receivers with a jack connector as external antenna connectors, so I made two cables with F-connector to jack plug. They should be used for the 27.555 receiver (up and running), and FT8 monitor receiver. I still need to set up a computer with sound card input for that purpose. 

I have a monitor system like that running on 50MHz, and I would like to continue using that. Possibly a Raspberry Pi set-up.

Last year was a bit low on radio activities. I should have had a better antenna system up, but other, more urgent activities came in the way. The solar power system also needs an update. This should be a busy year. 4m and 6m antennas have priority, as the bands are good due to high solar activity. Some activity on microwave bands should be made, too, and I should finally get up a rotator, so I can rotate a small VHF/UHF/SHF antenna system. We shall see how much gets done this year.

Update:

It looks like the Sangean receiver is not suitable for FT8. (noisy local oscillator?), or not sufficiently sensitive so I will have to use another radio for that purpose, or build one myself. Still looking around.