[TowerTalk] rf burns

[Mickey Baker]

When n1ta asked the ground question, I thought "ding ding ding... We have a winner."

The reality is that, somehow, your transmitted energy found a path of low impedance through your body, likely to ground or what appeared (electrically) to be another part of the antenna system. You will likely continue to get zapped occasionally until you establish a common ground for the gear in your shack.

Try using extension cords, different antennas and variable coax lengths into your garage and travel trailer and you'll find lengths that will cause you to get burned there, too, or worse.

Or bring everything in your shack to nearly the same rf potential by establishing a good single point ground for everything and reap fringe benefits like a lower noise level.

Seriously, be careful - this is a safety issue. You could be hurt or killed.

Mickey 

On Feb 6, 2012, at 10:02 PM, chris casey <cscvrp at gmail.com> wrote:

> Yeah, so... I've never had a good ground. Right now the tuner and the
> rig are connected by a piece of #14 solid copper, and then the usual
> rig to PS to the wall.
> 
> Best I can tell I need to bring my station to a ground outside which
> is also tied to the service ground. But I can't find a service
> ground... So I know I'm exposed in the ground area to some fun.
> 
> The thing that I find strange is when I bring this in to the garage,
> or into the travel trailer, and connect things the same I have no
> problem. Yes its a different plug in the wall, so there are places
> where things can be different still. And I took everything apart just
> now, re-routed cables etc some, and the behavior changed but is still
> there... I need a way to check for RF that doesn't involve my
> fingertips. Thats awful.
> 
> I see some mention of high voltages created in the tuner and arcing
> etc, but I don't think I'm getting arcing but I'm not sure short of a
> movie style arc noise I would be sure...
> 
> Thanks.
> 
> On Mon, Feb 6, 2012 at 8:42 PM, Mike N1TA <mike at n1ta.com> wrote:
>> Hi Chis,
>> 
>> What type of ground do you have at your station (if any)?
>> 
>> Mike N1TA
>> 
>> 
>> -------- Original Message --------
>> Subject: [TowerTalk] rf burns
>> From: chris casey <cscvrp at gmail.com>
>> Date: Mon, February 06, 2012 7:01 pm
>> To: towertalk at contesting.com
>> 
>> So I haven an 80M loop I usually only get to use for sweepstakes every
>> year, rest of the time the feed line is coiled up in a tree.
>> 
>> I have had opportunity to bring it inside and setup a "permanent"
>> operating station. I've had grand fun, but see some weird behavior now
>> and then. When it was wet out a couple days ago while tuning (mfj
>> tuner, 450ohm window line feed) it would bounce all over. And more
>> often than not when I get towards a good match I start getting a growl
>> in my headphones. Tonight I got a doozie of a rf burn off my key base
>> which sets right in front of the tuner knobs. It will do this on
>> several bands, 40m down at the bottom of the band tonight.
>> 
>> I have a splice which I figure I'll cut upstream from and add a new
>> hunk in and add some length. Its a bit short and running right
>> through a pine tree, I guess I'll add some more feed line in and go
>> around the tree.
>> 
>> Same antenna with same feed line length matched all over the place
>> without issue when ran to the travel trailer for sweepstakes. Now if I
>> don't want nasty noises on TX I have to run an swr above 1.5 usually.
>> I worked HU2DX on 15M and TX6T/P 17M CW tonight on the first call so
>> it must not be just a stub of feed line 10' long to the splice...
>> 
>> Besides re-working the splice, and routing around the tree, any ideas?
>> 
>> --
>> 
>> -Chris
>> _______________________________________________
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> 
> 
> -- 
> 
> -Chris
> _______________________________________________
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