EBay Modules And Custom PCBs Make A Plug And Play Ham Transceiver

Many of us have fond memories of our introduction to electronics through the “200-in-1” sets that Radio Shack once sold, or even the more recent “Snap Circuits”-style kits. Most of eventually us move beyond these kits to design our circuits; still, there’s something to be said for modular designs. This complete amateur radio transceiver is a great example of that kind of plug and play construction.

The rig is the brainchild of [jmhrvy1947], who set out to build a complete transceiver using mostly eBay-sourced modules. Some custom PCBs are used, but those are simple boards that can be etched and drilled easily. The transceiver is only for continuous-wave (CW) use, which would normally mean you’d need to know Morse, but thanks to some clever modifications to open-source apps like Quisk and FLDigi, Morse can be received and sent directly from the desktop. That will no doubt raise some hackles, but we think it’s a great way to learn code. The rig is QRP, or low power, transmitting only 100 mW with the small power amp shown. Adding eBay modules can jack that up to a full 100 Watts, which also requires adding a 12-volt power supply, switchable low-pass filters, a buck-boost converter, and some bandpass filters for band selection. It ends up looking very experimental, but it works well enough to make contacts.

We really like the approach here, and the fact that the rig can be built in stages. That makes it a perfect project for our $50 Ham series, which just kicked off. Perhaps we’ll be seeing it again soon.


[via RTL-SDR.com]

9 thoughts on “EBay Modules And Custom PCBs Make A Plug And Play Ham Transceiver

  1. The eBay 3eur arduino nanos, AD9851 DDS modules and lately Si5351 modules have done a world of good for hamradio homebrewing.
    Now everyone can just casually have LF-40MHz and 9kHz-160MHz programmable local oscillators in their junkbox.
    No LC VFO stabilization needed by changing components to counter drift, no siting on a single crystal controlled frequency.
    For 4eur one can have a synthesizer that covers every hamband up 145MHz.
    What a time to be a hamradio homebrewer.

    1. I guess the PA is not wired in at the moment, considering that if properly built and biased, it will 40W on HF easily.
      And it has one of those “1.5W” linear amplifiers as a predriver.
      So yeah I’m suprised it’s only 100mW, maybe the PA is in bypass mode?

  2. TLDR – are there a lot of people sending/receiving morse code using software now?

    Long version –

    I have a couple of CW only transcievers. And yes, I also have the license to use them. I have been studying Morse code for years now. I guess it just doesn’t mesh well with how my mind works. I still don’t feel like I am good enough to venture out onto the air.

    Anyway, a few years back I rigged up a computer interface and tried them on fldigi. Receive error rate was very poor. Only the best signals were close enough to correct that I could really tell what they were talking about. Even that I could only understand because I could recognize words without all the letters being 100% correct. Callsigns however, well there was no way I could be sure that a callsign was being decoded correctly so actually making contacts was definitely out.

    Something I noticed was that I could get better decoding by adjusting the WPM. It wouldn’t last though and I would have to keep tweaking it. I tried a couple of Android apps too and had pretty much the same result. I even tried using fldigi to generate morse beeps in my computer speaker which the android app copied 100%. My hypothesis is that even the best human beings sending morse by hand have variances in their speed. A well trained human brain deals with this. A hard coded computer program however does not.

    I think that means that if I used my fldigi setup and found someone else who was also sending their code via computer we could communicate just fine. When I last tried years ago though I did not find anyone that seemed to be doing so. My gear has been gathering dust ever since waiting for me to feel comfortable enough with morse code to actually try to use it. Has the time come when I should be trying the fldigi setup again?

    I did try calling CQ one day when the bands seemed particularly dead. (I didn’t want a reply). I did that in order to get logged by the Reverse Beacon Network (http://www.reversebeacon.net). I was picked up by a station in OK which is about 1000 miles away from me. Having done that I verified that my setup actually does work if only I had the skills to use it.

    Someday I will get there and be able to send/receive morse by hand and ear. Why? It’s not that I have any particular love for beeps. It’s because simple equipment to do so can be built with only a handful of components and that sounds fun to experiment with. I have even heard of single-transisor 2-way transceivers!

  3. Does anyone know what the second RF stage on the “1MHz-700MHZ 3.2W” amplifier is? Some people seem to think that the first stage is a GaLI-74+, which has the right specs…

  4. I have said this to many people over the last year, and it is a little bit over $50 but the best entry radio in Bang for the Buck is the uBitx shipping case and all on the air for under $150.00 USD! THIS IS AN ALL BAND HF LOW VHF RADIO! It is also a multi-band all mode ShortWave receiver. I love the approach above but the uBitx is simpler and for about the same money with way better documentation and a large following who are continually modding and upgrading everything from the hard ware to the firmware. WB4IVG Laurin

    1. I love the idea of the uBitx and I’ll probably buy one and build it for the “$50 Ham” series, even if it breaks the budget a bit. But a kit is still a kit, and I’m also very keen to scratch build for the series. This module-based build is a nice in-between, so I might do that too. But there’s just something powerfully attractive about dead-bugging a couple of chips and tacking a few junk box passives down to a chunk of PCB and making a contact with that. That’s a skill I definitely want in my toolbox.

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