[TenTec] RFI and Orion Mic connector - bad info

Rob Atkinson, K5UJ k5uj at hotmail.com
Thu Apr 22 11:18:17 EDT 2004


I used to have my basement shack at the end of a 20 foot ground cable.  I 
was getting back into the game after being off HF for many years and I 
(obviously) had forgotten a lot about station building if I ever knew 
anything to begin with.  I moved the whole shack and cut the ground run down 
to about 5 feet.  Are you really sure you can't get closer to your ground 
rods?  If not, I can only think of 3 options:  1.  Tuned ground 
"counterpoises" one for each band or a matching network for one wire (MFJ 
"artificial ground").  These are wires cut so that on whatever band you want 
to use, one of them will be at a low impedence at your rig's ground lug. 2. 
Not having any ground at all.  Some hams claim this works for them but I'm 
not convinced it's a good idea.  3.  Drilling a hole or holes in your 
basement floor at your rig and sinking a rod or rods through the concrete.

Invest in a bag of 20 or 30 split bead ferrite chokes and put them on 
equipment leads.  (the brute force approach)  Expensive but you will be 
amazed at how quickly you wind up using them.  If a lead has a shield and 
the shield is only for that and is grounded at both ends try grounding it at 
only one end (the nonOrion end).

Take a look at this approach to deal with RF coming back in on the shield of 
coax feedline:
http://www.radioworks.com/nliinfo.html and coax ground loops.
While this ham is naturally trying to sell his line isolators, the 
information contained here
is still useful and worked for me as a solution.
I had awful RF problems with a Omni VI running 1 kw because my antenna is 
only 20 or 30 feet from my shack.  I shortened the ground run, used ferrite 
chokes on equipment leads, employed line isolators and the radioworks ground 
configuration and these techniques fixed my problems.
since this could be overkill for you, try what Bob said about testing one 
lead at a time.

Rob Atkinson
K5UJ

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