Greetings to the group,

Does any one have any specific info on retuning a Henry C200D10R UHF 
450-470 rack mount PA into the 440 band ?   The PA requires 5-10w to 
produce 100-200w out.  I can see nothing inside that is adjustable, 
all the components are fixed value and securely soldered in place.  
The only thing that might be adjusted is the spacing of the coils on 
4 wire wound chokes, 2 near the input  and 2 near the output.  

The PA belong to a friend who purchased it used from a 3rd party, had 
it shipped to Henry to put on 443.750, and return for use.  A simple 
bench test into a 50 ohm dummy load shows that (using a IC2400 mobile 
on low power) 8-9w in at 443.750 yields about 45w out but as I 
increase the freq. to 462.750 the IC2400 pwr drops to 5-6 w (which I 
would expect from from the mobile being out of band) but the PA 
output pwr. jumps to over 100w. 

My suspicion is that Henry did nothing but make sure it was working 
in the deigned band range(450-470) and slap a new label on it and 
send it back.

Will compressing the choke coils closer together make any difference 
in the freq. range, or do some of the fixed components need 
replacing.  I know the choke compression worked in retuning a ARR 450-
470 preamp to move it to 440 (per ARR directions).  If so, how close 
should the coils be spaced ?? 

TIA for any help
Doug  N3DAB 

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