I’ve been wanting to play around with echolink via qtel, but have been having trouble with the combo jack on my xps 13. When I would plug in a headset, it would see the headphones, but would never see that a mic was available. I think it is a problem with the sound card initialized in I2S mode. According to the Arch wiki, the kernel can be recompiled with the option CONFIG_ACPI_REV_OVERRIDE_POSSIBLE=y and it will force on HDA mode.

In the March 2016 edition of QST, there was a project that added an arduino/ad9850 vfo to a cheap ebay forty9er kit. In a happy accident, I had ordered one of these kits several weeks ago before I found out about this mod. The next day, after I found the project, my kit arrived. In a first for me, I also had everything I needed for the build on hand so I was able to get started right away.

Looking at the schematics for the various si5351 breakout boards, they all seemed rather simple. Usually, it was just the chip, a crystal, and some level shifters. They looked simple enough, so I figured I could throw something together myself. I picked up a few of the si5351 chips from digikey for less than $1 a piece. I had some 25MHz smd crystals around and it turns out, that is all I really needed to get the si5351 working with a raspberry pi.

A while back, I threw together a quick 40 meter dipole out 75 ohm rg-6 and some AC wire. I’ve mostly been using it with my receivers. So far it seems to work okay, but I have really had nothing to compare it to. I looked into purchasing an antenna analyzer and like everything else with ham radio, they seemed unusually expensive. Being a newcomer to the radio world, I was surprised to find radio equipment so expensive.

I put together a little crystal tester circuit that I found on w2aew’s youtube channel. It works well. I built it almost exactly the same way that Alan does in his video. You can see the sockets that were added to easily swap crystals in and out of the circuit. Here is the schematic. And here is the resulting waveform for one of the crystals that I tested in the circuit.

Continuing the saga of my homebrew direct conversion receiver, I rebuilt it on copper clad with some minor changes. I added an LM317T voltage regulator so I could power the RF amp and audio amp with 12 volts while the arduino and mixer can be powered with 5 volts. I ran into some problems with the regulator and while I was measuring the output, a slip of the DMM probe sent 12 volts into the arduino, popping one of the capacitors on its internal regulator.