[TowerTalk] shut fed tower and rotator

[K8RI on TT]

On 2/13/2011 1:25 PM, Gary Slagel wrote:
> I recently built 2 verticals for 80 and 160 by shuntfeeding my tower.  They both seem to load nicely and are broadbanded, partly because of an insufficient radial system. 
>   
> When I transmit on either 160 or 80 the meter on my rotator controller deflects.... this makes sense since I'm running rf right through the rotator.   Till now I've run only 100 watts thru the antennas but I'd like to see if the antennas will handle a KW ok.   I'm wondering if there's any chance of damage to the rotator (Ham IV) if I do this.   I'd guess not but it makes me a little nervous.

It could be coming in on either or both the coax or rotator cable.
As you are showing a good match, I assume the match is at the tower and 
you are not using a line tuner at the shack.

   When operating 75 at roughly 800 to a 1000 watts the LEDs on my 
6-pack and remote antenna switches would light. At the legal limit they 
were bright enough I was worried about damage.  I tried chokes on the 
cables, but nothing changed. Then I added a current balun where the feed 
line between the 75 sloper and the remote antenna switch reached the 
tower. No more interferrence.

The chokes/baluns I used were 5, 2.4" 31 Mix toroids with 5 turns of 
LMR-400.

I'd try one in the rotator cable near the control box to see what happens.

Read Jim Brown's (K9YC) RFI tutorial 
http://www.audiosystemsgroup.com/RFI-Ham.pdf about toroids, RFI, baluns, 
and audio interfacing.  It's well worth the time.

73

Roger (K8RI)
>   
> Currently 10 watts deflects the meter about 10%.  100 watts deflects it about 25%.
>   
> Anyone have a thought on this? 
>   
> Thanks,
>   
> Gary Slagel
> Hot Springs, SD
> N0SXX
> http://marina.fortunecity.com/sanpedro/351
>
>
>
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