Hell, I could spend a week on top of a mountain with an Oscilloscope, Spectrum Analyzer and function generator and still not trace down what is actually happening.
Survey says: Incidental AM from a weak tube in the FM tranmitter final stage coupling to DC power leads as an antenna and then being rectified with the polarity protection diodes and filter capacitors into AC and interfering with power supply of op-amp's VDD and VPP. Using a ferrite around the cables may help as well as placing the controller in a RF tight enclosure. Feed through capacitor DB-9s may be nessacary as well. Then if you are still getting the noise, it could be the carrier actually being rectified on the silicon inside the op-amps, in which case your screwed. Also not as likely but could happen, the site power is actually modulating with the FM transmitter and the repeater power supply is not able to filter it out. This can be proven by running the station on a battery and the audio goes away. On 2/13/07, Ken Arck <[EMAIL PROTECTED]> wrote: > At 10:09 AM 2/13/2007, Ken Arck wrote: > >Have a customer with the following issue: > > > >Scenario: Amateur repeater (Mastr II) installed at a 100,000 FM > >radio xmtr site. > > <----Make that 100,000 watt (at least the claim is 100K) > > Ken > ------------------------------------------------------------------------------ > President and CTO - Arcom Communications > Makers of the world famous RC210 Repeater Controller and accessories. > http://www.arcomcontrollers.com/ > Authorized Dealers for Kenwood and Telewave and > we offer complete repeater packages! > AH6LE/R - IRLP Node 3000 > http://www.irlp.net > > > > > > > Yahoo! Groups Links > > > >
