July 25, 2005

220 remote base repaired


Tonight I finally FIXED the Icom IC37a 220 transceiver so that we shouldn't have any more problems with the 220mhz audio received not making it to the repeaters. The volume pot on the unit (which controlled the audio going into the repeater) had numerous 'dirty spots' and it would always seem to find a way to NOT pass any audio after a while.

I have replaced the worn out volume potentiometer with an internally mounted, brand new, hermetically sealed, 10 turn pot-- which should provide reliable service into the next ice age.

While at the site I charged the backup battery, reset the repeater clock to the correct time (it had drifted off by 5 minutes since last December), set the packet TNC clock, and replaced the RF cable from the 440 duplexer to the GasFET preamp with a cable made with superflex heliax. I also attempted to remove the additional 440 cavities (on loan from N8JKV), but it appears that the main duplexer is tired and in need of replacement or refurbishing. The system works as it is presently, but there is an extra 1.5db of loss in the system (both RX and TX) due to these extra cavities. I'll get a new duplexer on site within the next few months, and we'll squeak a few more miles out of it at that time.

73 KF8KK

July 16, 2005

Link RX frequency reset


Sadly, due to caring for my dad, N8NCO during his final days (and the funeral issues), it took a few weeks to tend to the apparent frequency drift that the UHF receiver used in the link from the W8TVC site to the Empire repeater had developed. As the weather approached 90 degrees the receiver would drift further down the band, as the temperature moderated, the receiver would drift back toward normal reception.

Tonight I managed to spend an hour at the repeater and found that the receiver was tuned for 440.043--- seven khz low-- and just outside the range of 'useable'. I reset the receiver to the proper frequency and the system appears to be functioning properly now.

I also reseated the connections to the 6mtr duplexer and in my checks did NOT notice any of the odd noises that were intermittently present on the 6m received signal (no noise present both before and after the connector reseating). There is, however, a somewhat questionable connection in the factory 1/4" superflex connector at the polyphaser, which I will tend to soon.

More maintenance work to commence later this week as my schedule gradually returns to 'normal'.