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Re: [TenTec] RF Getting back into Rig Problem

To: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Subject: Re: [TenTec] RF Getting back into Rig Problem
From: joel hallas <jrhallas@optonline.net>
Reply-to: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Mon, 20 Mar 2006 08:51:29 -0500
List-post: <mailto:tentec@contesting.com>
Dave,

It certainly sounds like RF getting into the radio!

Sometimes good grounding helps, but it is often even more important to 
find out how the RF is getting there and stop it from doing so. The 
possible sources that occur to me:

RF on the coax shield - a good ground at the rig might make a big 
difference here. Also check that the coax connector backshell on the rig 
is tight. Finding out if you have the problem with a dummy load instead 
of the antenna (unlikely) may be worth knowing.
Power leads, possibly coupled directly from the antenna if it's close or 
more likely from the power wiring. Try a different source, shorter 
leads, better a car battery close to the radio.
Speaker or key  or mic (even if on cw) leads. Unlikely, but easy to 
eliminate or, for the key, make very short.
Computer connections. This can get coupled from phone lines if you have 
a modem, power wiring, etc. Easy to pull off and see.

Once you know where it's getting in, you can address the problem more 
directly with a coax  choke (6 to 10 turns of coax 10 " in diam, for 
example) on the feedline, ferrite beads on other wires, etc.

Having a good ground is not a bad idea, however, you may already have a 
fair ground through the green wire of the ac line, if you're close to 
your power panel and it's installed properly. It will help some but not 
all of the sources above, and could even make some worse, depending on 
how the rig wiring is set up.

Just my $0.02.

73, Joel

Dave Tipton wrote:

> 
>  The facts:
>  Rig: Jupiter with Auto Tuner
>  Antenna: 40M dipole at about 20 feet.
>  Coax: 100 Feet of RG8X
>  Keyer: MFJ Memory Keyer
>   
>  Over the weekend, we had some horrendous rain storms.  This is the first 
> time I've ever encountered this issue, so I question whether that had 
> something to do with it.
>   
>  Now, I'll be the first to admit, I do not have a ground on my rig.  That's a 
> problem, I'm working out this week.  (10 inches of rain this weekend should 
> help that actually)
>   
>  Whenever I ran more than 50 watts, CW, the rig would key and then lock in a 
> transmit position.  Turning it off and then back on would release it.
>   
>  My question(s):  Is this merely a grounding problem, or am I overlooking 
> something else?   Has anyone else ever experienced this?
>   
>  Thanks,
>  Dave, W3DMT
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>  
>


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