KPC3 to Phoenix
Home Up Phoenx Audio Service Tips


My favorite radio to use in APRS applications is the GE Phoenix radios.    This is a 1980's vintage programmable synthesized radio.  It can easily put out 35 watts.  Best of all, you can pick them up for $20-50 at the ham fests.  To find out what features and bands a Phoenix can do, go here.

For a great site with lots of information about the Phoenix radio click here.    For lots of great diagrams about TNC/Radio connections, go here.

Here's what to look for.  This is a fully loaded Phoenix.   It has scan which goes to waste in this application.   Some older models are beige

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First thing you'll need is a friend with a programmer.   Ask around for hams that work at shops that have done GE work.  They might have the required programmer.    Niles Radio also makes a clone that works.  Here's more information how how to make a programmer.

If you have some time, and need to program these radios often, it might make sense for you to build your own programmer.   There's one that GE used to sell that allows you to program the radio in hex.   Here's the manual.    You'll also need a table to convert frequencies and other codes to hex.     That's a manual about 2" thick.  

RF wise they seem to work pretty well.   But don't run them at low power.    Spurs go way up as power goes down.   Very strange reaction, but I've seen this on quite of few Phoenixes.   35 watts seems to be a good compromise.   Once you're above 35 they're very clean.   Sensitivity has been good.   And they seem to do better in high RF areas than typical ham rigs.   I use the discriminator (filtered vol/Sq Hi) output.  The volume setting isn't important this way.  Use Software Carrier Detect.

You might notice I'm feeding power FROM the radio TO the TNC via the radio connector.    The KPC can be powered via the radio connector.  When you do it like this, you don't need to coaxial power connector that always seems to fall out and short to ground.   I'm taking power out of the radio.   P910 - 1 and P910 - 11 are connected together in every radio I've worked on.

In case you don't have a manual for the radio:  P911 is the 8 pin connector.    It's Pin 8 is closest to the coax connector.  P910 is the 11 pin connector.   It's Pin 11 is closest to the coax connector.


Now, here's the scoop on the wiring.   You'll need some parts.

Bill of Materials:
11 circuit terminal housing, .156 Digi-Key WM-2109-ND
8 circuit terminal housing, .156 Digi-Key WM-2106-ND
Pins for above Digi-Key WM2300-ND
Male DB-9 Any
6 conductor cable, 10" Any, shielded would be nice.

The cable length is up to you... but since I keep my TNC on top of the radio, 10" is fine.

KPC3 DB-9 Pin KPC-3+ DB-9 Pin


Use My color Phoenix Pin Power
1 1 TXA Yellow P911 - 4
3 3 PTT Violet P911 - 2
5 5 RXA Orange P910 - 4
6 6 GND Black P910 - 8
7 7 POWER Red P910 - 1
9 9 GND Shield P911 - 3
P910 - 11 13.8 V in
P910 - 6 Power GND

Where you're all done, here's what the radio should look like from the back.    Nice and neat. 

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Be sure to check the Service Tips page if you're having trouble with your Pheonix

Parts sources:  Mouser  or DigiKey

If you have any additions or corrections, please e-mail me, KD4BBM

Last rev 01/14/08 13:11

Except for portions owned by others, Copyright: Ray Vaughan, 2008