Category Archives: Homebrew

Transceiver new build 1

The workshop clean up was delayed, I just had to get the VFO working. When I built the kit a few months back I did not solder one of the headers! Found that this afternoon, soldered it and all was well.

First job was to setup the IF at signal frequency + 9Mhz. Then a quick run through to see if all the functions were working as they should.

I like the minimal display. It would be even better to be able to go back to using one the old Eddystone slow motion drives like this one on a G2DAF RX from 1963. No water falls, flashing lights, bleeps, tones or warning messages on screen. Don’t get me wrong there is a place for all of that but sometimes I just want a radio that is simple and easy to operate without the need for an A4 ring binder full of instructions.

G2DAF RX at the national radio museum

At the end of the afternoon this is what I had; a VFO covering all bands from 160M – 10M with the IF set to 9Mhz and giving about 80mV P-P of sine wave ready to go straight into the mixer.

Building an HF Transciever

Over the years I have built a lot of gear from simple test equipment to an eight band CW transceiver using reclaimed parts. Technology moves on and I now have three commercial SDR rigs. The performance of modern transceivers is amazing but I feel something has been lost; it’s all done in software which feels a bit cold, clinical even.

A few years back I followed a series of articles in RadCom written by Eamon Skelton, EI9GQ, where he described how he built a transceiver mainly from discrete components. I bought the book a couple of years ago and now feel I want to make my version of his project.

Why now? It is mainly the availability of cheap test equipment like spectrum analysers, VNAs, GPS locked frequency meters and wide band noise sources which work well with SDR receivers like the RSP1A.

Not long ago all we had were grid dip oscillators, drifting sig gens and frequency counters with dubious accuracy.

I have made a start and almost fallen at the first hurdle! Instead of making a 9Mhz, 2.4Khz wide SSB filter I have bought one from Spectrum Communications. That will save buying lots of 9Mhz crystals and spending hours matching them to get a good shape.

I have already built a VFO based on a synthesiser chip. There are some things it is not worth trying to replicate and a drifting VFO is top of the list. I did build a free running 8 Mhz VFO in the early 1970s that was multiplied by 18 to drive an old Pye valve TX on 2M. It took hours to sort out the drift but eventually it was rock solid. The key was an Oxley Tempatrimmer. The fixed vanes of the capacitor were fixed to a bimetalic strip so as as the temperature varied the capacitance changed. They are impossible to find these days.

Watch this space as I will post progress reports as each stage is completed. The first thing to do is tidy up the workshop, I may be some time…

Norcal-40A

Had this kits for a while. Built it but at the first attempt it did not work. Tried again a couple of weeks back and got it going! Must admit to getting the biggest kick from making something and then having a QSO.

Had a bit of trouble with the faulty, cheap, trimmer caps and idiotic SOIC to pin converters for the NE612s but after going back the the DIL versions all was OK. It still needs tweaking and putting in a box.

Could not resist trying on an antenna, heard a MM station, gave him a call and he came straight back!

10 July 20
It’s in a box, just needs wiring up.

FMT Morse Tutor boxed up and working

The Morse tutor is complete. I chose a plastic box that was only just big enough, I like a challenge and this certainly was one! It all worked out OK in the end but was a real fiddle to get the measurements right.

What I learned apart from home construction is fun:
1. A nice bezel hides a lot of mistakes!
2. Covering a plastic box in masking tape prevents it being scratched when drilling and filing.
3. Removing the glue after covering a box in masking tape is not easy.
4. Red is always the positive wire on battery connectors!

Phoenix Kits Online

FMT Morse Tutor MK3 kit

I can’t think of a better way to spend a wet and windy Sunday afternoon than building a Morse tutor! It is from Phoenix Kits Online and grew out of a FISTS CW Club Project designed by Paul, M0BMN.

Twenty years ago I learned Morse using an MFJ-418 Morse code trainer. While it was good the design was a outdated which made repetitive – the character generated were not random.

The kit was easy to build. It too around a couple of hours and worked first time. Now all I need is a box.

As I have been away from Morse for a while I wanted to get back up to speed. What is really pleasing is that the code has stuck in my aging brain so maybe with a bit of practice I will be back on the air soon.

A 2m transverter

I know you can’t really call this homebrew as all it needs is the two boards mounting in a box and wiring up. It was fun though, and irritating as it was a bit of a tight fit. The relay board was tested and the PTT line works. Now it needs a bit of RF from the G90 to see if there is output on 2M. If all is OK then I will need to find/make an antenna.

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.

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!