TopBand: 160M RF into Create RC5A3 Rotor Box

[km1h @ juno.com]

On Mon, 8 Sep 1997 01:19:08 -0400 (EDT) K1ZM@aol.com writes:
>Hi guys
>
>I wonder if anyone out there has had probs with 160M RF entering the 
>rotor
>cable of a Create RC5A rotor?

SNIP

That control box contains a number of op amps Jeff. Also included is a
very sensitive  servo amp which is driven by the preset pot and the pot
up in the rotator. 

Looking over some old notes I found that I cleaned up a similar problem
many years ago by adding some .1mF caps on the circuit board. I would not
use .001 for 160M, that is a value more appropriate with VHF. 

Terminals 4,5,6 on TB-1 are the ones to follow. They go to PC pads D, H,
G respectively. Pad F is ground. Run .05 to .1 mF caps from D,H,G  to F. 

You should hopefully notice some improvement. It may now be the time to
try the ferrites again if there is still a problem as you start going
full QRO.  

It may also be advisable to place ferrite at the Inv V feed point to
reduce currents on the coax outer shield. If that coax is running next to
the control cable all sorts of RF can be coupled.

73....Carl  KM1H 

  

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