WC2XSR/13 Station Log

Station Log of WC2XSR/13

by W5JGV

January 1, 2003 - December 31, 2003

This is a copy of the Official Station Operating Log of Part 5 Experimental Radio Station WC2XSR/13.

It is presented here in reverse order, so that the latest log entry will appear at the top of this page. That way, you don't have to scroll through the whole thing to get to the new log entries. Since this log is transcribed from my notes, the wording tends to be a bit clipped at times, but, hopefully, the meaning will be clear.

31 DEC 2003 - The year ends with not much to report. The transmitter and antenna system has been quite stable, and continues to perform very well. Outages have been very few, and mostly for scheduled checks and maintenance work.

13 JUN 2003 - Transmitter off the air from 1806 to 2359 CDT due to primary AC line failure. (The power cord was accidentally pulled out of the wall socket!)

As soon as the transmitter was restored to service, a thunderstorm broke over this QTH and the antenna current decreased about 25%. This happens whenever the trees near the antenna get wet from the rain.

The transmitter frequency is 166.500 KC. The modulation is QRSS30, sending "XSR" one time, followed by CD ID at 10 WPM, then the entire sequence repeats. The transmitter power output to the antenna is 400 watts.

22 APR 2003 - For the last month, the transmitter has been running with no problems, 24 hours a day.

This afternoon, at 1730 CDT, I shut the transmitter down so that I could work on the roof directly under the end of the antenna next to the antenna tuner. At about 1840 CDT, the transmitter was placed back on the air. The frequency has been changed back to 166.500 KC. The modulation is QRSS30, sending "XSR" one time, followed by CD ID at 10 WPM, then the entire sequence repeats. The transmitter power output to the antenna is 400 watts.

09 MAR 2003 - The majority of the winter season is behind us for another year, and, as the trees begin to sprout leaves, the antenna resistance has begun its annual upwards climb.

Today, I adjusted the PA supply voltage upward from +24 volts to +28 volts to maintain the 400 watt output level from the transmitter. Nothing much has happened since the last log entry on 20 JAN 2003. For the most part, the system has performed flawlessly. A few small tree branches, which were blown about by the strong winter winds, managed to interfere with the antenna tuning occasionally, and caused a few hours of lower than normal power output.

The changes to the Antenna Tuner have apparently been successful, and no arcing failures haven been seen in the tuner.

The modulation is QRSS30, sending "XSR" one time, followed by CD ID at 10 WPM, then the entire sequence repeats. The transmitter power output to the antenna is 400 watts. The carrier frequency remains at 164.500 KC for the present time.

20 JAN 2003 - The transmitter was shut down between 1519 - 1820 CST today for modifications to the antenna tuning system.

The 10 position loading coil tap switch was removed and a motor-driven 3 position tap switch was installed in its place. This will allow operation on 166.5 KC for transmitting, and on 185.x KC for LOWFER reception, plus a spare tap for future use, possibly in the MF band, should that particular frequency allocation be restored to WC2XSR.

About two weeks ago, I installed a motor-driven servo system to remotely adjust the variometer coil from the operating position. Although the electronics for the automatic tuning function is incomplete, manual operation is available, and lets me quickly adjust the variometer when the weather changes and causes detuning of the antenna system.

Also in the future - I have most of the necessary parts, but have not started assembly yet - is a remotely controlled adjustable impedance matching system to adjust the match of the coax line to the antenna system as conditions change. This, in conjunction with the servo controlled variometer, will allow a more constant loading on the transmitter as well as a more constant radiated power from the antenna under most environmental conditions.

11 JAN 2003 - The transmitter was placed back on the at 1739 CST.

The modulation is QRSS30, repeating "XSR" one time, followed by CD ID at 10 WPM. Transmitter power output to the antenna is 400 watts.

The frequency has been changed to 164.500 KC to facilitate possible reception by several stations who have reported interference on 166.500 KC.

Modifications were made to the transmitter yesterday and today to allow the use of an external frequency control signal from the HP3586C Selective Level Voltmeter which is used at this station for receiving. The control signal is taken from the HP3586 at a frequency of 2664 KC and divided by 16 to obtain a carrier frequency of 166.500 KC. Because the transmitter requires a TTL square wave signal and the HP3586 provides a 1 VPP sine wave, a sine-to-square wave converter was designed, built, and installed in the transmitter.

Since the front panel of the transmitter is rather crowded, it was necessary to remove the FAN power switch and move the PA POWER ON switch to that location. A new switch was then installed in the spot vacated by the PA POWER switch. This new switch is used to allow the input to the divide-by-16 stages in the transmitter to be connected to either the internal 2664 KC Precision Oscillator, or to the existing front panel jack (which was used for a test output signal from the internal Precision Oscillator.) The front panel jack now functions as a test signal output when the transmitter is using the internal oscillator, and as an external oscillator input jack when using the HP3586 as the carrier signal source.

5 JAN 03 - Transmitter off the air at 2040 CST for listening tests overnight.

1 JAN 2003 - Transmission continues as before.

Transmitter power output is 400 watts at 166.500 KC.

The modulation sequence is: The ID letters "XSR" are sent once in QRSS30 mode, then "XSR" is sent twice in QRSS10 mode, then "XSR" is sent three times in QRSS3 mode, then the following plain text is sent three times in 10 WPM CW, "DE WC2XSR/13 DE WC2XSR/13 QSL VIA W5JGV". The modulation sequence then repeats.

73, Ralph W5JGV

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