[RFI] Kenwood ts-850sat RFI issues

Jim Brown jim at audiosystemsgroup.com
Mon Mar 15 11:37:57 PDT 2010


See http://audiosystemsgroup.com/HamInterfacing.pdf  Do these steps in order, 
and stop when it's fixed. :)   

1) Bond every chassis to every other chassis, INCLUDING THE COMPUTER, with 
short beefy copper braid (like what you can strip from good RG8). On some 
computers, you'll need to go to the retaining screw of a DB9 or DB15 
connector to find the chassis. 

2)  Add a ferrite choke to the interface cable tuned to the transmit 
frequency. See http://audiosystemsgroup.com/RFI-Ham.pdf for detailed winding 

3) If you have a real serial port, you can build a simple Kenwood interface 
into a connector. It's nothing more than a zener and a resistor or two. Poke 
around on the internet to find details. Works great with N1MM, Writelog, and 
Ham Radio Deluxe. I've used it with legal power, both in Chicago with 
antennas only 20 ft from the radio, and here in CA with antennas more spread 

4) Study my serial cable built with CAT5. That solved some really severe RFI 
between my computer and my K2/100 back in Chicago.  


Jim Brown K9YC

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