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1. CW Monitor. This is the first of the transmitter-related stages, and described on WB5RVZ as usual. The build was uneventful and concluded with hearing a pleasant tone in the headphones when the key was pressed.
I installed a 2-pin ramp header connector on the board in the space available. The connectors are not provided with the kit.
2. PA Rx/Tx Control. Documentation is on WB5RVZ for this phase of the construction. A simple build, no complications except for power.
The main power connection is in this area of the board. No ramp connectors were provided with the kit, and it turned out the power needed some non-standard size (at least in my world). After some persuasion with the Dremel tool, I mounted a standard 0.156" Molex KK connector as shown in the photos.
When testing at the end, SX1 properly switched from Rx to Tx. SX2, on the other hand, wasn't so clear: after tracing out the circuit a bit, the cryptic "KP" stensil means that the connection is for the key and PTT. Not quite so sure what the testing with SX2 and the DB-9 connection was trying to accomplish, and with no reason to suspect problems, I skipped over it. On to the next section ...
3. Tx Sample-and-Hold. Refer to WB5RVZ and to Phase 9 in the Genesis documentation. Construction was in three separate areas as highlighted in the first couple photos. Resistance and voltage tests at the end were as expected.
In addition to the half-inch standoffs on the bottom, I also added some of the hardware I had left over from DB-9 connectors. Those standoffs weren't especially long, so I used several at once at each corner. Keeps the components from abuse by the bench top when I'm working on the bottom of the board.
4. Tx Driver and PA. This last part of the build at WB5RVZ starts with a video of the G3020.
By the time I got to the last step, attaching all the wires on the bottom, I realized that there was a better alternative for connecting the PreAmp/Attenuation switch. The unused pads at the top right were a perfect place to put a 3-pin ramp header, so I made that modification as well as adding the various jumpers.
5. Final Step and Adjustments. Here's where we get to check everything and see how it's going. See WB5RVZ as usual for this one; printed the sheets to record the data.
All the voltage checks measured as expected until I got to the PA Bias Test. How do I put this into transmit mode? Back to #2 above ... I needed to go to Tx there too, and couldn't get a handle on it. It's a software issue ...
- Following the directions at http://genesisradio.com.au/G40/9assemblyG40.html
- The shop PC runs Win-2000 and has a real COM1 serial port (no USB)
- Running PowerSDR SR-40 version 1.9.0 (because GenesisSDR won't run on Win-2000, at least not yet).
For the first time in the build, I connected a serial data cable between the PC and the G3020. One of the advantages of being in this for years is that I had (almost) new RS-232 tools to help diagnose the link. Anybody remember the DB-25? From the setup instructions, I expected DTR to control the Rx/Tx switch. Not. When I clicked "Tune" in the software, RTS went high and a relay or two clicked on the board. The red Tx LED didn't go on though; after verifying VRx and VTx were operating properly, I discovered the red LED was bad. Replaced it and added a parallel LED at the end of about 8 inches of wire for a front-panel Tx indication.
Aside from really pushing the shop PC for CPU cycles, the program does seem to run. The LO is set to 10.125 in a setup window. The carrier supression and Tx image adjustments described by WB5RVZ don't seem to work as expected, so I need to go to the GenesisSDR program to swap I&Q on Rx, and I expect on Tx as well. When I listen to RF output, and check with frequency counter, the results don't match the settings expected. I'm still trying to figure how to move the several vertical lines on the screen and tune the radio. [It was a s/w setup issue: needed to check the "Drag Filters" option.]
The good news amidst the confusion is that I get power output. When I crank up the audio going into the G3020, the wattmeter went right up there. One freq + image probably, but at least the amplifier works!
GenesisSDR wasn't working with Win-2000, and Goran (yt7pwr) kindly helped with an update to the code. Yes, it did finally run, but the hand key plugged into the G3010 stopped working with this new revision. About that point I decided to upgrade to Windows XP, but even the simple upgrade was a hassle, and wasted a day back and forth to the PC as it rebooted for endless updates, service packs, and .NET. Finally did get it working.
PowerSDR SR-40 runs as before, and the key also works. Comparing the setups leads me to conclude that the GensisSDR program is the way to go.
At this point, the radio seems to be working. My computer environment probably needs more tweaking for it to see active use on the air.
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Genesis G3020 SDR 