The Ethernet transformer mixer with 1N4148 diodes works great! There’s a contest on 40 today and I have heard Italy, Spain, Russia, Germany, Britain, Belgium, the Netherlands, Switzerland, and Sweden on this radio with that mixer in the last hour. My transformer package contains two sets of transformers. Here I’m using only one set. But for a superhet radio you’d have two mixers worth in a small package. #HamRadio #AmateurRadio
I designed and 3D printed some subdividers for my Lidl storage drawer set so that I can put a lot of small components in there. Very happy with this! #HamRadio #AmateurRadio
If you are building your own radio stuff, this looks like a pretty darn great deal on a (5 pack of) 6W-capable UHF MOSFET:
https://theelectronicgoldmine.com/products/g28282
Ship to limited countries, be warned.
I got a much better video of my direct conversion receiver listening to SSB, after band conditions improved.
Very pleased with this radio! #HamRadio #AmateurRadio
I got a good idea from PA0PHH that you can use cheap Ethernet transformers for RF mixer transformers. Man, they are cheap. I ordered 10 for €8.25 from Aliexpress. Each one has two sets, so one will do a whole mixer. Cheaper than toroids and no faffing with trifilar windings! I will give it a try when they get here. #HamRadio #AmateurRadio
I got my direct conversion receiver working! Band conditions are not amazing at the moment, but you can clearly hear the SSB I was listening to.
I designed and assembled a case for my Pi Pico/Si5351 VFO that makes it a lot easier and safer to move around on the bench. Good learning for my 3D printer skills. I am working on a knob design but for now using one that’s a little short. That OLED is blue/yellow and looks good. #HamRadio #AmateurRadio
I finally assembled my Soldersmoke DC Receiver last weekend but it was not working well. I spent the week debugging. I could receive CW well but not SSB. It is very garbled. I swapped around some parts and tracked the problem to mixer build!
Today, I built a drop-in ADE-1 based mixer to test... and 💥 beautiful SSB. So I have to debug my mixer. I have a little oscillation in the audio amp, but here's a video showing how good it sounds when right #HamRadio #AmateurRadio https://youtu.be/Rvzcj72Q8lc
If you’ve seen my toots about the Soldersmoke direct conversion receiver and wondered what that was about, the Soldersmoke podcast guys put out this video this week that gives a great summary. You might like it #HamRadio #AmateurRadio https://youtu.be/5pLHBWkNxmM?si=r5xWiVFbFRDQBOge
I finished the last board of the Soldersmoke direct conversion receiver today: the 40m band pass filter. Only, I didn’t have the specified type 6 toroids. I had T68-2s, though. In the end I ended up designing my own 40m band pass filter with totally different values. Took me all afternoon, but I ended up with a very solid result! Very low loss, acceptable match.
Look at those big Soviet trimmers in there. Tested them with the NanoVNA and they are very close to spec. #AmateurRadio #HamRadio
NanoVNA screen zoomed into the pass band, showing that the 40m band is well covered.
NanoVNA screen showing filter performance. Blue line shows pass band and extremely low loss. Yellow is SWR and reasonable. Green shows Smith chart performance.
40m band pass filter on copper clad board, using T68-2 toroids and Soviet trimmer capacitors.
I had an idea… I saw 3D printable coil formers for antenna coils. VU2ESE used printed forms for the Daylight transceiver.
I started to think about the tiny PITA coils I made for my VHF amplifiers. So, I designed and printed a few of these little guys and am going to test these out tomorrow with the NanoVNA! These will be nanohenry ranges.
I may do one that lays down and has blocks on both ends as 2nd trial. These might seriously improve my life for small inductors.
That actually worked pretty well. Self-made card edge adapter for HP ham shack power supply. Soldering down those slots a little tough but was able to get a good solder joint along about an inch of wire on each side. Fits nice and tight so it won’t come off. Need a little more clearance for the resistor soldered on the left. Otherwise good. #electronics #HamRadio #AmateurRadio
Plastic adapter housing and prepared 1mm FR4 board that will make contact with the HP power supply card edge adapter.
Adapter fitted to an HP power supply, with wires attached and slots filled over with hot glue to cover exposed terminals.
My first self-designed 3D print worked out awesome. It’s a case to mount the speaker I bought for the Soldersmoke direct conversion receiver project. Very happy with this. That’s the audio amplifier board and soldering supplies in the background. #HamRadio #AmateurRadio
Mixer and audio amp work! Don’t have the rest of the Soldersmoke direct conversion receiver done yet. But I used the digital VFO for my 2m radio homebrew project to feed the LO port on the mixer. Used my 2m FM HT to give some signal toward the exposed end of the coax. At first I heard just screeching. Then realized one side of one toroid was backward phase. Fixed that and could hear myself on the speaker! 🔊 #HamRadio #AmateurRadio
At IRTS Hamfest in Mullingar yesterday, I picked up these two (working) Yaesu 80s era linear amps for €15 ea. They do 10W with maximum 1.5W in. The 2m version is all discrete components inside while the 70cm uses a Mitsubishi RF module. The 2m will be perfect to run as the power stage for my 2m homebrew project if I get that completed. Had never seen these before and think they’re pretty cool. Seemed like a great price. #HamRadio #AmateurRadio.
Internals of 2m Yaesu linear amplifier showing circuit board. Note: missing parts were never installed and nothing has been removed.
70cm Yaesu linear amplifier internals, showing circuit board. Note: missing parts were never installed and nothing has been removed.
Two small Yaesu linear amplifiers stacked on the workbench.
This is my version of the Soldersmoke direct conversion receiver mixer and audio diplexer board. Missing an inductor that arrives tomorrow and then I can test it. Still have two boards to go. Not going to win any beauty awards with mine, but I’ll be happy if it works! This was about 4 hours of work, mostly spent laying out the board and then fiddling with trifilar windings. Learned some stuff though. #HamRadio #AmateurRadio
I built a second amplifier yesterday, with a better matching design. And got a worse result!
I eventually figured out that there is a fair bit of parasitic capacitance in my layout. I removed the 12pF capacitor in the input matching network, replaced it with a 1pF and rewound inductors to add enough inductance. It now looks close-ish to the Qucs-S simulation. No such problem on the output network. Not sure yet what the extra capacitance is on the input. #HamRadio #AmateurRadio
After a little more tuning and some really valuable help from @n8dmt (!) I have a working self-designed antenna amplifier. I learned a lot. I will make a second version that has better wideband matching and is better constructed (I hope), given what I've learned. Here's the amplifier showing FM broadcast and APRS signals before and after. #HamRadio #AmateurRadio
APRS signal before and after amplification. Without the amplifier, it's below the noise floor.
Waterfall display of FM Broadcast signal showing no amplification
Waterfall display of FM Broadcast signal showing dbFS with amplifier running
@relistan Curious to see S11 and S22 if you have a NanoVNA or other capability. What was the gain? 3dB bandwidth? Thanks & 73
@n8dmt I don’t have a scope or sig gen. But I used my SI5351-based VFO to test gain with the TinySA and I tested S11 with the NanoVNA. I’m not sure how to test S22 because the power out is higher than the NanoVNA can take and if I pad it that will obviously mess up the measurement.
I tested gain through a 23dB pad I made so as not to run over the TinySA. Bandwidth I will try to test with the VFO/TinySA.
None of it is exactly what I got from Qucs-S but I expected that! #HamRadio #AmateurRadio
Well the amplifier I soldered up last weekend that didn’t work has been fixed and seems to do what it’s supposed to. The soldering job is not going to win any awards for sure. But with the amount of rework I did, and my surface mount experience level, I think this is fine. It’s hard to tell here but the whole circuit (not the board) is smaller than the first two joints on my little finger. #HamRadio #AmateurRadio
