USB Soundcard / PTT Interface complete.

I built the USB Rig interface that I mentioned in my last post and it turned out great.



I have it interfaced with my old Icom IC-281H.  I made a few changes to the original plans.

1) Instead of the PS/2 connector used in G4ILO’s setup, I decided to use a TinyTrak/KPC3 compatible DB-9 Radio interface cable.

2 ) I also omitted the bypass switch.  I didn’t think I would need it.

3) I left out the trimmer pot (I forgot to buy it, tried it without it and it works fine…)


I am very happy with the result… I am now running an APRS base without spending a lot of cash on a hardware TNC.


Thanks again for the great circuit G4ILO!

My next mini-project

Just found this link to a homebrew USB interface for digital modes.  This is just the ticket for helping me build my shack.  I am using a modern laptop with only 1 serial port and I want to save that for my FT-847 CAT port.    I also can’t see paying $99 for a commercial interface.

I have build a lot of soldered kits over the years, but at some point I want to learn proper circuit board creation techniques.  This is a pretty simple circuit so I should be able to use this opportunity to learn how to do proper circuit prototyping.

I just ordered 4 (!) of the sound cards referred to in the article off of eBay.  Total cost with shipping?  Less than USD $8.

Great work G4ILO!

G4ILO’s Homebrew USB Radio Interface




Note to self…. look into this SDR when you get some free time.

Morse code is suddenly cool!

Got an old KPC-3 TNC? Want to use it for APRS?

Check this out… I will be trying this soon.

Wise words from a very smart girl.

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