[BC] Re: Copper program Loops

[K7qa@aol.com]

You really dont need an expensive equalizer unit or a vulnerable opamp lashup 
to make up for the high end loss on such a circuit using the 111-C repeat 
coils at each end of an unloaded pgm loop. 
You can produce a reverse mirror image of the rolloff curve by using a simple 
resonant circuit with an adjustable insertion potentiometer. Use a 2.5 mH RF 
choke in series with a 5 K pot. Then place a 0.1 mfd cap across that to start 
and tack the entire network 
across the 111-C secondary winding at the receive transmitter site end. Send 
alternate 1000 Hz and 10 kHz tones from the studio end and adjust the pot as 
necessary to make the receive levels the same. If you need response flat to 
15 
kHz or to flatten the response to within 1 db, you may have to reduce the 
size 
of the cap, or the RF choke down to 1 or 1.5 mH. This is basically the same 
circuit found in the WE TellLabs equalizer.

tm




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