[Elecraft] Computer noise problem

Mon Mar 24 13:22:01 2003

Unless you have taken steps at the transformer to suppress common mode current back onto the shield, the shield all the way back to the rig is part of the radiating antenna. Even grounding it at the antenna end cannot prevent this in all cases. 

Adding the counterpoise has changed this dynamic. 

There is nothing magic about coax that makes it per se immune to being part of the radiating system. Unless you have taken specific steps to block it, it IS part of the radiating system. 

73, Guy.

> 
> From: "Bozidar Benc" <[email protected]>
> Date: 2003/03/24 Mon PM 12:43:53 EST
> To: <[email protected]>
> Subject: [Elecraft] Computer noise problem
> 
> Hello,
> 
> PC in my shack generated lot of noise on my K1, especially on 40 m band.
> When I replaced PC's power supply with an older one, the noise decreased
> almost by half.
> 
> My antenna was 20m long wire with 10:1 transformer at the end, which is
> connected to my K1 with 20 m of RG58 cable.
> 
> Now the interesting part.
> After I added a 10 m long counterpoise to the antenna, the noise from my PC
> almost completely vanished!
> 
> Does anyone have any explanation?
> 
> Another question: Is it clever to ground my K1, and if it is, where on K1 is
> the best place to connect ground?
> 
> 73, Bole, 9A3RR
> k1 #1499
> 
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