[Kenwood] counterpoise

[Rob]

I don't know what a TM-D700 is, but usually when you throw a wire on  
the floor to use as "ground" it has to be 1/4 w. for the band of  
interest.    So you need one for each band you operate on.   This is  
the basic principle of the MFJ "artificial ground."  it's just a  
matching network that lets you use one wire for all bands by adjusting  
it's inductor tap and capacitor so the wire gives the rig a low  
inductance (inductive reactance) "ground" independent of frequency.

But, having written all that, are you sure you need any of this at  
all?   In many cases, a rig will work fine not hooked up to any  
ground.  Unless you have RF in your tx audio, or you get a tingle  
feeling when you tx and touch the rig's cabinet, mic, key etc. you may  
need nothing.   I used to run my TS870 with it bonded to a ground  
strap going to a shack ground buss which is bolted to a 3 or 4 inch  
wide copper strap going outside to rods.   The 870 had some distortion  
problems so I simply removed the ground, thinking there might be a  
ground loop or RF above ground potential and the problem went away.    
870 is perfectly happy with no ground.

73

rob / k5uj


On Jan 18, 2009, at 3:11 PM, Van Jackman wrote:

> I have the TM-D700 in my second floor shack. If I run a RF ground  
> all the way to earth it functions as an antenna disrupting other  
> electrical circuits in the house. How can I use a counterpoise to  
> produce an artificial ground and eliminate these problems? The TM- 
> D700 has no direct ground connection except the mobile screws on  
> each side. Is this enough for the counterpoise? do the counterpoises  
> need to be of different lengths for the different bands?
>
> Van
>
> Kenneth V. Jackman, M.D.
> 132 Moss Rock Road
> Saranac Lake, NY 12983-3502
> WA2DPM
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