10V Regulator Card Modified

Looks like the 10V Regulator Card in the VHF repeater was swapped while on the site last weekend.

Modifications necessary to make a 10V Regulator Card work for a repeater full duplex station.

Modifications necessary to make a 10V Regulator Card work for a repeater full duplex station.

As a result, I had to modify it to match up with the

“repeater station” circuit needed to prevent the repeater from “repeating” on its own without an external controller (like it was this morning).


Also found sucked out (improperly installed) PL-259 fittings on 4 of the 8 connectors on the interconnection cables.

I also had distorted audio when connected to the controller and when connected through the GE stock repeater card. The NHRC7 controller was fed off of the discriminator audio which would have come directly off of the system monitoring board. Moving the RX Audio over to the SPEAKER HI terminal on the back of the system control shelf resolved the audio issues.

There are still some hum issues on received audio that do not show up on controller generated audio (such as after COR opens during hang time, courtesy tone and CWID). Monitoring from a scanner with tone decode, it appears the GE board, which decodes the 100.0 hz PL tone, does not seem to filter out the subaudible tone. Subsequently, the hum on the transmitted audio appears to possibly be retransmitted CTCSS tones from subscriber radios keying in to the receiver.

This audio issue was not previously apparent utilizing the commercial CSI TP3200 controller as it has high pass filtering in place (and regenerates true tones as programmed or none at all).CSI TP3200 Tone Panel to NHRC-7 Controller

The 9914 Nm-Nm jumper appears to have been the only good coax jumper amongst the lot taken with the repeater off of the mountain. I cut it in half and soldered on new PL259 connectors. The output ports for the RX and TX on the Mastr 2 are SO239 (UHF) connectors. The input ports to the duplexer are Nf connectors. By putting PL259s on the radio site and using the existing Nm connectors on the duplexer side, I’ve been able to remove 3 extra adaptors previously in use.

Also looked in to a few options for continuing to use the CSI TP3200 Community Tone Panel for tone encode and decode.

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.