Xiegu G90

In a rare (opinions may vary) moment of madness, I have ordered a Xiegu G90 mainly fo portable operation this year. Now it is antenna building time. The first will be “A twenty metre portable antenna” as shown in issue 178, Spring 2019 of Sprat by Paul M0PNN.

Hi-Fi SSB?

A few years back it was fashionable to use ‘HiFi SSB’. The idea was to transmit a much wider AF frequency range with the emphasis on getting more bass response. I remember hearing a station who was proud of his studio mike and loads of processing gear. His signal had lots of bass and extend higher frequencies. His bandwidth was nearer 8Khz than the usual 2.4Khz. He said he did not care because he had spent a lot of money getting ‘better’ audio.

Years back I was taught that the frequency range for intelligible speech was 300hz – 3.4Khz.  I find that lots of bass makes signals harder to copy, especially when they are weak. Which is exactly why the military and aviation communications limit the bass response.

Why spend lots of money on expensive ‘studio’ microphones and other fancy audio stuff when all it does is make your signal less readable? Is it the just the dealers making money again? Is it the desire to be different or ‘one-upmanship’? Or is it a lack of understanding of what radio communication is about?

Home construction, QRP, solar power 8 months on

When I came back to amateur radio in March 2018, I set myself some aims, more aspirations really.  I said that I wanted the station to be QRP, all homebrew and solar powered.

I have always enjoyed making stuff and now I have finally retired I have a lot of time to do just that. Second, I have previously thrown money at the hobby, got on the air and become bored.

QRP? Life is too short say the kilowatt cynics. Over the years I have enjoyed using a lot of small, home made radios with spectacular results. It takes more effort to winkle a signal out of the noise, but the rewards are bigger. Like many things in life it takes effort and patience to get results but the reward are higher.

uBITX

As the solar power I am trying to reduce my carbon footprint as I fear we are on the brink of a climate catastrophe.  You may not agree but I would urge you to read the evidence, from climate scientists, not newspaper articles, who agree that there is a big problem. Besides saving energy in the home saves money!

80w folding solar panels

So, 8 months on I am back on the air with a uBITX with the mods to reduce spurious emission and harmonics. Next is the AGC board. Using a LiPo battery I can get near 20W output but that is trimmed down to 5W. I also have a 20M QSX and am eagerly awaiting the launch of the multiband QSX.

20m QCX

The auto antenna tuner is nearly finished but in the mean time I have a 9:1 balun at the bottom of the antenna and an L match at the radio end. I can get below 1.5:1 from 106m to 10m which is fine for now.

The only thing to sort out now is a more permanent solar panel battery charging facility. I have the gear from ‘the van’ but want something more permanent.

80M DX on the uBITX

This is a recording of W1MBB on 3.798Mhz at 0754 this morning. My antenna is a long wire strung between two trees with a homemade tuner. I also heard a ZL this morning.

 

So, what does this prove? That the uBITX receiver works well although I must add the AGC board! That there is DX out there if you know where to look. That amateur radio need not cost a lot. And, most of all, there is nothing to beat the kick of building a radio and using it on the air.

I know I could never work him on the uBITX but I also know that using higher bands it is perfectly possible to work across the pond on 2W of CW.

ARISS SSTV award

Got my ARISS SSTV award today from a download last weekend. I used the homebrew antenna, a Baofeng and a portable recorder to record the audio which was uploaded to MMSSTV. It was a low pass of the ISS, never more than 19 degrees above the horizon and around a minimum of 1200km. I reckon I picked up the sig when they were over the mid-Atlantic and lost it when they were over Chad. So, I am pleased to get the award considering the basic equipment used. Now on to bigger things, a tracking rotator and 2M plus 70cms crossed yagis for circular polarisation. All homebrew.

 

Low cost frequency standard

I have been looking for a low cost frequency standard for a while to replace one I once had about 10 years ago. The only way to do it then was to build a GPS locked oscillator. I chose the extreme overkill route and locked a doubtful rubidium standard to GPS. It worked for a while and then the rubidium kit stopped working.

The next solution was to lock a temperature-controlled 10Mhz crystal oscillator. It worked well enough as along as it was left on all the time. Recently I have been looking for a cheaper and less complex way of providing a 10Mhz standard signal for test equipment and radios.

Things have moved on and the GPS modules that used to be relatively cheaply available on ebay are no longer there. Ditto oven-controlled oscillators. Then I found the ideal solution on the QRP Labs web site; a “ProgRock – triple GPS-disciplined programmable crystal” which is basically a Si5351A chip programmed for a single frequency. It can be GPS locked via a 1PPs signal from a GPS receiver, the “QLG1 GPS Receiver kit.” An order was placed.

The kits arrived, and I spent a few hours yesterday building them. As usual with QRP Labs kits they all worked first time. The first check was my £17 ebay counter, a Racal-Dana 9918. It was 5.2Hz low at 10Mhz! I could try adjusting the internal 10Mhz oscillator but it might take a while to get it to read 10,000,000!

The better option is to complete the project by building a small distribution amplifier which will give 3, 10Mhz sine wave outputs from the ProgRock and use one of them as an external timebase for the counter.

The PrgRock with scope probe attached

GPS board with patch antenna.

The kits, parts for the distribution amp and a case will cost around £35 in total. That is probably about one tenth the cost of the previous project!

Is this all overkill? Well yes and no. Modern transceivers are accurate but when you build your own you never know. Also, the move to VHF, UHF and microwave for satellites means I want to be sure that the frequencies are correct. This crucial when multiplying up free running crystal oscillators as any error will also be multiplied.

The usual disclaimer, I have no connection with QRP Labs other than being a satisfied customer. This review/article was not solicited by them and they had no knowledge I was doing it.

 

Why home construction?

I am often asked why I bother with home construction. Why make stuff when it is so easy to go out and buy it? The questioners sometimes go as far as asking why I waste my time.

There are lots of reasons; it is something I have always done, it saves a lot of money, you know your gear well so can repair it and most of all I learn something, sometimes the hard way!

All of that is summed up in this quote I found today:

“The excitement of learning separates youth from old age. As long as you are learning you’re not old” Rosalyn Sussman

First test of the remote ATU. The control box is the next job.

I am now eight months in to my aim to build a totally homebrew station. I am at the point of having some working transceivers, power supplies, an antenna analyser and a long wire antenna. The remote tuner is almost done but is proving troublesome. By the end of the year it will all be sorted!

More DX on 80m

Another listen at the top end of 80m this morning produced more DX –  ZF2ZB. He was calling CQ or QRZ and was eventually answered by a Canadian station which I could only just hear. Still amazed at the performance of the RSP1A SDR RX fed by the untuned long wire.

When I first heard him at 0755 he was 5-7/8 but I had problems with a faulty memory card in the recorder. On this recording he was 5-5/6 but it was 0805 by then. At 0830 he was still just there in the noise but I heard KC4GL call him.

Slow scan TV from the ISS

At the third attempt I managed to copy an SSTV image from the ISS. It is noisy as it was orbit 1924 which showed a minimum distance of 1038km and maximum elevation of 19.15 degrees.

I used the dual band antenna I made last week with a Baofeng GT-3 and a Zoom H5 audio recorder. It all worked well enough but a bit more gain at 2m would have helped. I am thinking of making crossed yagis for both 2m and 70cms. As the wind chill was somewhere around -3C today the new antennas will be motor driven!