How to keep RF out of my other electronics?

binrat

Observer
I don't have an SWR mtr handy, but signal reports are great.
There is something going wrong with your install or you have a really cheaply built stereo. I would highly recommend checking the SWR on the antenna before anything else. Even antennas that come "pretuned" may require tuning for you installation.
 

Arctic Travelller

Adventurer
There is something going wrong with your install

As I said, power wires go direct to the battery, all the coax and the antenna are new. I agree that I should check the SWR, but Unforetunately, I don't have an SWR meter. What could be wrong with my instillation of the raido?
 

Russ Chung

Observer
Jeff,

I had a similar problem where my external amplified speaker would squeal when I transmitted. Some of the previous responses suggest that the problem is on the 12v DC side of the system (between the battery and the transceiver) and others have suggested that it is on the RF side of the system (between the transceiver and the antenna). In my case, it was a combination of things.

The first thing we need to do is to determine whether the interference is originating from the 12v DC or the RF side of your transceiver.
1. Does the problem occur when you transmit on low power? Does it occur on both 2m and 440? Do you hear any noise on your stereo before the protection trips?
2. Temporarily run a pair of wires directly from your battery to your transceiver (bypass the distribution block in your console and put a fuse on the power lead). I have a hunch that the problem is not on the 12v side, and you will still trip the protection on your stereo
3. Disconnect your antenna cable at both ends and buy or borrow another cable and run it directly between your transceiver and your antenna.
4. If your stereo still trips, then make sure that your antenna mount has a good ground and make sure that your stereo has a good ground.
BTW, my problem was that RF energy from my antenna cable was "leaking" into the wire that feeding power to my external amplifier. I re-routed the power cable and the antenna cable so that they ran on opposite sides of my Jeep.

Russ
KI6MLU
 

4x4junkie

Explorer
I'd almost bet $$$ that the coax cable is "hot" with RF, and is why it's tripping out the stereo. ×2 it's probably a faulty coax connector, or the antenna mount isn't grounded properly (if it's a magnetic mount, the shield connection to the bottom of the mount might be open).


FWIW, I have a SunSaver MPPT-15 solar controller. Indeed it was very noisy below 30MHz (about 5-7 S-units of a wideband whistling/swishing noise), along with a few "birdies" (I guess you call them) scattered throughout the VHF range... I took the controller apart and shielded the plastic housing and put bypass capacitors on the panel & battery terminals... This cut the interference down tremendously at the top end of HF (and no more birdies on VHF) though it still interferes a good bit on my AM BC receiver (I might need to switch out the .01µF bypass caps I used for .1µF). Most-effective would be to put the controller into it's own shielded box w/bypass (feedthrough) caps on all the leads going in & out of it.
 

binrat

Observer
As I said, power wires go direct to the battery, all the coax and the antenna are new. I agree that I should check the SWR, but Unforetunately, I don't have an SWR meter. What could be wrong with my instillation of the raido?

The routing of your power wires, the routing of your coax, as someone has stated the coax being hot which means possible poor grounding at the antenna end.
I had a friend who had a big amp for his stereo along with a 2 meter rig in his car. Power wires to the amp were about 6" away from his coax and he had issues. It only happened when his amp was running, moved the cabling apart and problem solved.
 

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