[CQ-Contest] RFI Question

Tom W8JI w8ji at w8ji.com
Tue Nov 6 09:51:22 EST 2012


> In the recent SS-CW, I noticed that I was getting RF into my PTT line that 
> I use for keying. ( the rig locked up on some bands when I was QRO)  I 
> suppose that I need to get the cable wrapped around some cores.What do I 
> need and where can I get them?
>

Carol,

What equipment is bothered, and on what bands?

The general trend is to just throw beads at any RF related problem, but the 
universal band-aid doesn't ever fix the **real** problem causing the 
sensitivity to RF.

A patch like that is OK if everything else is as correct as reasonably 
possible with the equipment and system, but the RF problem could indicate 
something else not done properly that might be hurting in ways you do not 
know.

If you are getting so much RF into the system that equipment is 
malfunctioning, it is a good idea to at least look things over for defective 
wiring, installation, or construction.

If you just happen have a device that is built poorly and is abnormally 
sensitive, then the beads are a cure.

If you happen to have a bad cable, lack a balun, have a poorly designed 
balun or antenna feed, fixing the actual problem  (instead of a bead toss) 
can help your system work better for transmitting and receiving.

The only case where beads might be legitimately required are where a piece 
of gear is unfixable, or where the antennas are so close they produce 
abnormal field levels in wiring.

73 Tom 



More information about the CQ-Contest mailing list