Re: KC3EF Mobile Equipmemt


Rick - N7WE
 

When doing the initial shakedown on my /P setup for the car (hamsticks on mag mount, center of the CRV roof) I tuned the hamsticks with a MFJ 259B.  But when I put 25W into it from the rig, I had enought RFI inside the car to cause the computer to go all wonky and the SWR up substantially.  Bought a Balun Designs Model 1110 - QRP 1:1 Isolation/Choke Balun 1-54 MHZ, SO-239 connectors in and out.  It was about $50 as I recall.  It is rated to 300W SSB even though it says QRP.  So it is easily good for 75W continous modes.  Put it in the coax about 12" from the base of the Mag Mount and RFI disappeared.  SWR also went back to the tuned level.  My conclusion...I had massive common mode on the coax without the isolation.  These are great little chokes for PSKers.  I used another on the EagleOne off the back of the motor home as motor homes have lots of circuits (like furnace blowers, smoke alarms, vent fans, etc.) that just love to suck up RFI and do strange things.  I'm told, but haven't verified, that common mode on the coax can mess with your radiation pattern too. Of course, YMMV but that was my experience.
Rick - N7WE
070 - #1602

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