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