147.080+ Repeater Realigned

On 2/7/09, Russ, N7SMA & AJ, K6LOR met up to realign the 147.080+ Mastr II VHF repeater that was previously up on Wilderness Ridge. We are happy to report that, after some interesting “tail chasing”, the VHF repeater now sits at a very reasonable .18 uV sensitivity as measured by a calibrated HP spectrum analyzer and is spot on frequency, plus or minus a few hertz, with 26 watts out at the P/A. The remaining desense issues are in three distinct locations that must be resolved:

  • Repeater to Duplexer Interconnection Cables
    • Receiver to Duplexer
    • Transmitter to Isolator
    • Isolator to Duplexer
  • Duplexer to Antenna Cable
  • Antenna

In order to trace down the desense, the interconnection cables are the first to be replaced as they’re already a mismatch of cabling:



Belden 9914

Belden 9913

The overall consensus of the repeater building community is that anything other than Heliax-type cable will likely result in some form of leakage, contributing to desense.