May 29, 2005

TVC voter alignment


Today a new 6' equipment rack was installed in the W8TVC hat room to replace the former 4' rack that was overwhelmed with gear. The new rack has adequate space for the equipment in use, and some additional area for possible future expansion (it also looks nicer).

Once the gear was moved to the new rack (all of the voting receivers for 444.725/52.92, link tx/rx, and backup 145.27 rptr) the alignment and adjustments were checked. It was suspected that some of the audio levels had drifted downward.

Apparently the 52.42 receiver output was about 3db lower than it should have been. The audio levels were set to provide a -3db output from 144.67, 449.725 and a -4db output from 52.42.

The 440.05 transmitter was significantly on frequency and at 10w output power. The 52.42 receiver appears to be about 2khz low in frequency. Retuning of this receiver (involving changing caps in the channel element) will be done at a later date.

Alignment checking of the Empire end of the voting system will be done soon.

John KF8KK

May 16, 2005

6m RX freq adjustment and more


Today (er, Saturday) I spent some time with the Empire 52.42 receiver and managed to bring the crystal 'right on' the desired frequency. When I arrived on site I found that it had drifted even further down the band than when it was last measured. Today it was receiving at 52.417 and last December it was at about 52.418. Sadly, the channel element (with xtal installed by Bomar) never really was able to make it to 52.42 (the 'ordered' frequency) since it was received. There is a similar (though not as far off) problem with the 52.42 receiver at the W8TVC location-- that will be tended to in the next few weeks.

While spending time with the repeater, I also changed the remote base inactivity timer setting so that it would have more of a tendency to unlink the remote base if there was no activity. The timer had been set to 30 minutes, which would never time out when certain repeater frequencies were dialed up (those with ID's that beaconed). The setting has been reduced to 7 minutes, which SHOULD allow the system to time out and unhook the link if no QSO develops when the link is turned on. This should alleviate some of the problems should the remote base be enabled and then the controlling station find themselves out of range unexpectedly. For those who are wishing to monitor a remote system for a scheduled QSO my best advice would be to kerchunk now and then to keep the link up.

Additionally, I attempted to set the 'DTMF second tone mute' for both 6m and 440. I thought I had done this a few weeks ago, but it seemed that it was just active on the 440 side. After entering the codes tonight, it seems as if it's no longer active on either port. Yet another gremlin shows it's ugly head in the controller. If things operated as they should, when you hit a DTMF sequence the first tone should pass through the system and all the rest be muted. I also shortened the 'inter-digit-dtmf-mute-time'... so that the muting period is shorter. These muting parameters are being changed in an effort to possibly eliminate the randomly intermittant 'dead carrier keyup' when stations come in on 52.42 and their audio does not pass through the system (but their COS/PTT does). The next step in this line is to remove DTMF muting entirely and see if that eliminates the manifestation of the problem.

Of interesting note is that numerous times today, while entering DTMF commands, the system blurted out erroneous command responses--- and would, at times, put the repeater into unusual operating modes. For those entering DTMF commands, please let me know if the repeater comes back with a response that doesn't make sense. The machine may need to be reset at that time also.

Otherwise, life is grand!.... er, ducky.

73 KF8KK