Small Solar Power Update and More.

 The output from the solar panels has been very low the last several weeks, actually most of November.

I can hardly power my IC703 all day with the current solar input, even if it has improved a bit with the new MPPT charge controller. Some more solar panels should be mounted, but working outside in near freezing temperatures is no fun, so it may have to wait until spring, or if we get some mild and dry days. 

For just monitoring of the low HF bands 20,30,40,60,80m I should use the small Chinese built HB-1B CW transceiver when not at the radio desk, as it uses less power than the 703. The spectrum display of the 703, after all, is only useful when I am there looking at it ;).

With the current very high price for electricity I am looking more at reducing power consumption for the shack. The stand-by/monitoring system has been reduced at the moment until I can get some really low power gear built and/or put to use. Yes, there are options.

Then there is the heating. 

Recently I got an air-to-air heat pump mounted, and now it is finally connected to mains power in the correct way. Yes, I had the electrician here, and at the same time I got an outdoor connector made for charging my new "toy car" (yes, fully electric, running on batteries).

It does look like the mains power consumption is lower than last year, in spite of the fact that I used gas heating last year, and electricity to power the heat pump this year. It will be interesting to see how things will work when I get more solar power up and running. I am aware that going off grid is not possible with the garden I have available, especially in December/January, but any reduction of mains power usage is welcome.

Mini-Lab Downstairs.

While I do have a mostly complete lab upstairs, it will be nice to do some home construction at the operating position downstairs, and have at least some test equipment there. This mostly for simple constructions and kit building.

Here is an overview of what I have for work downstairs, with a few ideas for improvements.

- Soldering iron and antistatic mats.

- 2 Multimeters (DMM).

- single channel portable oscilloscope (100MHz?, more like 30MHz, but OK)

- LCR-multimeter (not for very low L and C values, but a start, a better one is upstairs)

- Nano VNA (900MHz Fundamental wave generator up to 300MHz)

- Nano VNA (SAA2) (3Ghz)

- (Both Nano VNAs need to be tested with a simple diode multiplier for signal generation above 3GHz, e.g. 3.4, 5.7 and 10GHz)

- Tiny SA, low cost spectrum analyzer up to 960MHz, base scan about 300MHz. (The bigger/better one is upstairs, anyway).

- frequency counter, up to 1.3GHz. Under warm-up-test. Looks like it needs a bit of burn-in to age the OCXO crystal a bit more. It has moved 5Hz @ 10MHz for now, and seems fairly temperature stable at normally changing room temperatures, < +/- 1Hz. If better stability is needed, a GPSDO can be adapted (10MHz out to 1MHz in as counter reference frequency).

- a GPSDO, 10MHz and a distributor/extra OCXO. More power supply needed.

- (I should set up some more power supply downstairs for testing. I have an older one (up to 1A w/fold-back at over-current/short circuit) that needs to be tested. Output voltage should be 10 - 15V. Claimed max current 2.5A, but looks like insufficient cooling for that.)

- (For more test equipment a 12V (not 13.8) supply with several Ampere output should be available. Must be linear to avoid noise/ripple on the output.) (Also usable for the microwave converters/transverters.) Some equipment does not like the 13.8V, and should have just a 12V supply voltage.

- for now, a few battery cases with 3x 18650 Li-Ion cells (9.5 - 12.5V), and a few Ni-MH rechargeable sets are available. (4.8V, 7.2V, 9.6V available, a casing for 10 cells (12V) can be made.)

- Charging for Ni-MH cells set up.

- (Charging for Li-Ion cells needs to be set up.)

- I think I will need a more advanced linear power supply for the downstairs lab. (There is one upstairs) I should go see if I can find something suitable. Something with both voltage and current limiting. A simple SMPS or DC/DC converter with those functions may be sufficient for quick experiments. I think I can find one in my pile of modules - 12V input buck/boost converter with 3 - 24 (30) V out, with digital meters and settings ;).

- A small set of components for experimentation.

If you can think of further improvements please consider leaving a comment.

I do have more test equipment upstairs, and that will come into use for more elaborate testing and building. It does need some (a lot of) tidying there, though.

10GHz HB 100 Test With Modulation.

 Today was an active day with the soldering iron.

As the very first test I just connected the HB100 modules, preset to 10375MHz and 10450MHz on the desk, just to see if I could hear the carrier with my LNB mounted outside the house, and pointing away from the house. This is the LNB I have used for beacon monitoring, so I know that it works.

A primitive modulator using the LM386 PCB module with gain control (from China) connected to the 5V power supply (yes, 7805) was tested, making sure that the peak voltage would not be too high for the transistor in the HB100 module. This initial test was done with a 150 ohm "DC-dummy-load" in place of the HB100, and the LM386 input was connected to the earphone/headphone connector of a transistor radio. The voltage swing was about 50mVpp, so well within the limit.

Time for an on-air test. I connected my QO-100 base radio for TX, without RF output, and used the CW side tone to modulate the system on 10450MHz. When the HB100 was in an optimal position the wideband FM modulated CW signal was loud and clear in the receiver. Not very strong, but with significant quieting and a clear CW. My callsign has been sent out on 10GHz.

What I need to do now is getting the system into a box with switches, a tone generator the modulator, likely an electret microphone and a bias tee for the LNB, plus connectors for getting signals and DC out to the LNB and HB100, and the IF signal in from the LNB, and I should have a working system.

Right now I do not have any stations to test with, but a local amateur has a HB100 module and LNB somewhere, so he might be available. Otherwise I may have to build another system, so I can get some tests done.

The transmission distance tested right now is about 8m, so there is plenty of room for improvements.

More Scatter on 10GHz.

 My 10GHz receiving setup is still very simple.

Consisting of a modified LNB at 4m height (better frequency stability because the reference oscillator for the PLL is inside the living room). No dish or additional horn antenna. Indoors the signal is fed to a AR-8600 receiver receiving the IF of 618MHz.

With this simple setup I can hear 2 beacons, OZ7IGY at 26km and OZ9GHZ at 36km distance.

Most of the time OZ7IGY is quite weak (S2 or so) due to the landscape blocking the reception, but either tropo-scatter or reflections on high voltage lines/masts provide this signal.

When we have rain, even light rain, the signals are enhanced, sometimes up to S7 or so.

This winter I have also seen snow scatter. It sounds much like rain scatter.

When I get a better system up and running, directional (horn or dish) antenna, and a transverter, I will have to see what can be heard and possibly contacted further away. Even if my location is not very good, I suspect that some QSOs would be possible with the 2W amplifier I plan to use. Because of  visibility, I do net expect to work with a big (1m) dish up in the air, so I will have to see what can be done with less. Some directions will be OK at my location, others will be very difficult, but using scatter events I should be able to do a little.

I suspect that my first 2-way tests should be made with a 17 - 20dB horn antenna. Not ideal, but one step at a time.

For monitoring the band I may set up a box with 2 or 3 LNBs (switchable) with SDR back-end, for wide angle monitoring of beacons and activity on the band.

More Work On the 10GHz Beacon Monitoring System.

 Today I got the 10GHz RX beacon monitor outdoor work done:

- extended the stacked fiberglass mast by about 60cm, and got a modified LNB mounted just under the feed point of the 2m/70cm vertical used for monitoring "Raketten" (a local 2m/70cm cross band repeater), and turned the LNB in the correct direction, close to WSW.

- got the cables in through the wall, so the utility room window can be closed properly again. 

- connectors for the RX system and the reference frequency system (F-connectors)

- a satellite signal splitter for the 25MHz signal was sufficient to supply both the beacon monitoring system and the QO-100 system  with a decent temperature stability.

Future improvements: 

- Improving the reference frequency generator(s). Will probably use, initially, a 25MHz ref for the beacon monitor LNB and maybe a second 25.xxxx ref for the satellite RX, providing an IF of 434MHz, so a "proper" receiver can be used. I have TCXO(s) for those two frequencies. 

- converters for both LNBs for using amateur band receivers (2m, 10m, maybe 6m) as base receivers. Mostly for use with better CW filters than the AR-8600s have (they have no CW filter, and a rather poor SSB filter - Whether they can be replaced/improved I do not know - also lowest frequency step is 50Hz, too much for serious weak signal work - even good narrow filter CW work).

Another 10GHz Experiment. Murphy Canceled.

The OZ7IGY beacon has been reinstated on all bands but 2m (That one needed repair after the power cable had been cut by someone digging at the site.

Today the weather was quiet, so around noon I repeated the experiment with the LNB on the 13m telescopic mast.

This time the signal came up immediately with rain scatter, and a bit of tone now and then. 

The signals have been there for at least an hour now. Is it, maybe tropo scatter ? The rain radar does indicate some light rain in the area around the beacon.

The test needs to be repeated on a dry day.

This test indicates that it would be interesting to have a rotatable ,low gain antenna, system for 10GHz, for monitoring. A 10 - 15dB horn antenna is not too large to fit on top of a rotating structure. 

After an afternoon of testing, the signal is mainly (rain?) scatter, not much tone. 

The LNB has been lowered to about 9m, scatter signal still there.

After the end of rain scatter, with the LNB lowered to about 9m, the signal is very weak, coming in and out of the noise, but it is mostly there. Given the temperature drift of the LNB 9750MHz LO, it can be tricky to find the beacon. It looks like it needs just 10dB more gain, then the signal will be there, almost constantly. 

Final experiment today:

Lowering the LNB to about 3.6m, and moving it to a position where the trees at the other end of the garden do not block the view in the direction of the beacon. The signal is quite weak, but generally audible. With the LNB pointing towards OZ7IGY, the OZ9GHZ beacon in a direction about 60 deg. offset is quite audible, with S-meter deflection.

While writing this, sitting in the other end of my living room, I can hear the OZ7IGY from the speaker, quite clearly. I suspect there is a little bit of evening tropo, because before dark the signal was barely audible, but with a stable receiver and a good CW filter it would be 100% readable.

I have achieved another goal in phase 1 of my 10GHz activities, hearing OZ7IGY on a more regular basis, all with a very simple receiving system:

- a PLL-LNB, unmodified

- a bias tee for the LNB

- a "scanner" receiver, the AOR AR-8600 receiver.

I am quite happy with today's results.

The next step will be using modified LNBs w/connection for an external reference frequency (25MHz). Then, possibly more gain and a rotating receiving system.

Pixie Transceiver Kit Building and Mods.

Over the pas year or two I have eBay'ed quite a few kits of the simple Pixie CW transceiver. Now was the time to build and test a few, one as the original and one modified.
All those kits are so cheap from Chinese eBay'ers that I can buy 3, sometimes 4 kits for the tax free limit to Denmark (about 12 - 13 USD). I purchased a few, then another few. For that low price the kits are excellent for experimenting.
More modified will be built, for all the lower bands, but here is the first impressions:

Kit #1: 40m CW on 7023kHz:
The kit is easy enough to assemble. I made good use of my PCB holder for stability.
Resistor marking was good old standard. Some markings were missing on capacitors, so they were checked. The inductors were checked, as well, as I was not sure of the colour coding for those.
First impressions of the finished kit. It was expected to be tricky making contacts with such a low power device only capable of operating on a single TX frequency.
Power output, measured with a SWR/power meter is estimated to be just over 300mW. A trim-potmeter varies the oscillator frequency for receiving, so a decent "side tone" can be achieved. For receiving an old speaker was connected. A low hiss was audible, but the audio level was too low for comfortable operation. Further, some odd noises and distortion were heard (more about that later).
The first test was done with a local friend and my low hanging HF dipole, at the massive distance of 3km (about 2 miles) ;) Reports received were 599 (yes, for real), but I could only give 539, most likely due to the low audio level.

The strange noises were identified, the LM386 did oscillate, apparently triggered by strong signals received. Not good.
An Internet search revealed that this is a general problem with the LM386 in this configuration when connected to a low impedance (8ohm) speaker. A test with connecting the to a set of active computer speakers showed no oscillations or distortion at all. So much for the simplicity of the kit.
With the extra gain of the computer speakers the receiver is more lively, too.

Kit #2: 80m CW on 3560kHz:
Components from the original (2nd) kit, and some components from a third kit were used like this:
the values of the capacitors and inductors in the RF part of the circuit were doubled in value. The inductors from the 2 kits were connected in series, and the capacitors in the oscillator resonant circuit and the low pass filter were coupled in parallel. Interesting enough, it was quite easy to fit the parallel capacitors in the mounting holes.
That was all. Connected to the computer speakers the receiver sprang to life, and the sensitivity seemed OK, the noise level increased a bit when the antenna was connected.
My friend was not available at the first test, so no test QSO was made (yet)
Power output of the modified 80m was close to 500mW at 9V power supply. A bit more than the 40m version, but not surprising.

Running a CW transceiver at low power, and at single frequencies is, of course an exercise in frustration, so the next test will be modification of both kits for some frequency agility.
For the 80m version the first test will be replacing the crystal with a ceramic resonator and a variable capacitor. This should provide coverage of a good part of the 80m CW band.

The 40m version is a bit more tricky The resonator available is a 7159 version, and might not be capable of covering the CW band portion of 40m. I do have a 7.02MHz ceramic filter, and that might cover a part of the 40m CW band. Otherwise a VXO with some switched crystals available will be sufficient. Crystals available to me are 7.000, 7.015, 7.030 and 7.040MHz. With those I would expect to cover most of the 40m CW band.

It should be possible to make versions for the 6m, 160m and 630m bands, with other modifications. I should have the necessary replacement components available, but that is for later.

Update: The 80m version was tested today, and provided a 599+10 report from my local friend. It works, most definitely.