WC2XSR/13 Station Log

Station Log of WC2XSR/13

by W5JGV

January 1, 2005 - April 28, 2005

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.

28 APR 2005 - At about 2000 CDT this evening, I received a message from W5THT, Pat Hamel, who has copied the PSK31 signal. This is the first reception report of the PSK31 transmissions from this station. Pat copied the signal using DIGIPAN. The path length is about 67 miles between us.

28 APR 2005 - WC2XSR/13 SWITCHES TO PSK31 TRANSMISSION !

I put WC2XSR/13 on the air this morning at about 0345 with a loop composed of PSK31, followed by THROB 4, THROB 2, and THROB 1.

After listening from work, I found that PSK31 seemed to work much better than the THROB format, so I logged on to the control computer at home and changed the transmitter settings to run only PSK31.

The transmitter amplifier (it's the same one that I use for SSB) is being pushed pretty hard. It's sucking something like 20 amps (average) @ 28 volts from the power supply and almost 30 amps peak carrier. The heat sinks are pretty toasty. We'll see if it survives.

The audio control file for the PSK31 signal repeats the loop three times, then there is a break in the PSK31 signal of about three seconds as the loop file resets to the beginning.

13 APR 2005 - The first copy "by ear" report of the SSB transmissions of WC2XSR/13 were received from WA4LIP, Lewis Denton.

Lewis copied the signal at about 0930 CDT and sent this MP3 audio file of the signal. It is about three-quarters of the complete 42 second ID loop. Static punches a few holes in the signal, but it is readable. Thanks Lewis! The path length is about 135 miles. That's not too bad for a SSB signal, considering that only about a watt or so is actually radiated by the antenna system,

You can also hear what the audio ID loop sounds like as it is sent to the transmitter by listening to this MP3 audio file. Of course, the on-the-air signal is much reduced in frequency response because of the bandwidth of the audio circuits in the exciter and the narrow bandwidth of the transmitting antenna.

8 APR 2005 - At about 1930 CDT this evening, W5THT, Pat Hamel, copied the SSB signal. This is the first reception report of the SSB beacon transmissions from this station. Pat copied the signal with ARGO, and did not copy it by ear. (Correct me if I am wrong on this, Pat.) The path length is about 67 miles.

8 APR 2005 - At about 1620 CDT today, I took WC2XSR/13's QRSS30 transmitter off the air, and began carefully bringing up the power on the modified 400 watt SSB linear amplifier. At about 1745, the SSB amplifier was putting out a solid 400 watts of RF to the antenna system.

At 1943 CDT, I received the first reception report of the SSB signal by Pat Hamel, W5THT. Congratulations Pat!

The "Tree Effect" (from my neighbor's oak tree) is causing unwanted tuning changes in the antenna system when the wind blows the tree branches around. Occasionally the VSWR will change enough so that the lightning gap will flash over during modulation peaks. A real snappy signal!

I'll be putting together a web page on the amplifier and posting it on my web site- hopefully by early next week. Reception reports invited!

WC2XSR/13 is transmitting on lower sideband at a carrier frequency of 168.0 KC with 400 watts PEP transmitter output. The audio has a moderate amount of compression. An 40 second audio loop repeats the following message:

"This is Experimental radio station W C 2 X S R 13.

W C 2 X S R 13 is located in Jefferson Louisiana United States of America.

W C 2 X S R 13 transmits on frequencies between 163 and 169 kilo hertz.

Reception reports for W C 2 X S R 13 may be sent by email to W 5 J G V at W 5 J G V dot com."

26 MAR 2005 - At about 1900 CST, Murphy struck again, and the SSB power amplifier's PA2 output transistor quietly expired. The antenna current dropped to nearly zero.

While attempting to troubleshoot the rig, I boosted the drive a bit too far and, with a resounding "CRAAK!" the PA1 transistor vanished in a puff of smoke and flying debris.

The amplifier has been pulled and put on the bench for repairs, but due to time constraints, it may be later this coming week before I can get it repaired. Repairs to the CW QRSS30 transmitter are also on hold for the same reason.

The good news is that the spare transistors I ordered arrived today, I now have on hand ten brand new transistors to sacrifice to the Gods of the Aether.

25 MAR 2005 - At 2348 CST last night, the new SSB transmitter went off the air

This morning at 0430, I was able to take a look at it. I discovered that the amplifier had the +30 volt buss shorted solidly to ground. Upon disassembling the amplifier, I found that one of the PA transistors had a minor blemish on the metal back of the transistor. This slight defect caused the insulation between the transistor's collector (which is at +30 volts) and the grounded heat sink to puncture and short the collector of the transistor to the heat sink. The power supply went into current limit at about 34 Amperes and 1/2 volt, thereby protecting everything.

I planed the back of the transistor until it was very smooth and then carefully cleaned the transistor, insulator and heatsink and reassembled everything. A bench test showed that all was well.

At 1430 CST, reinstallation of the amplifier was complete, and promptly at 1500 CST the unit was back on the air.

24 MAR 2005 - At about 1600 CST today, I shut down the WC2XSR/13 CW transmitter which was running QRSS30.

I then installed the new 400 watt PEP SSB linear amplifier I just finished testing and connected the Starpoint channel modem to the amplifier. I will use the same power supply that's running the CW transmitter.

45 minutes later, at 1645 CST, I turned on the SSB transmitter for the first time. WC2XSR/13 is now running on lower sideband at a frequency of 168.0 KC with 400 watts PEP transmitter output. The audio has a moderate amount of compression. An audio loop id repeats the following message:

"This is Experimental radio station W C 2 X S R 13.

W C 2 X S R 13 is located in Jefferson Louisiana United States of America.

W C 2 X S R 13 transmits on frequencies between 163 and 169 kilo hertz.

Reception reports for W C 2 X S R 13 may be sent by email to W 5 J G V at W 5 J G V dot com."

The setup of the new amplifier went as expected, and the amplifier worked FB into the dummy load. But (there's always a "But") during the testing I managed to blow out one of the PA transistors in the QRSS30 transmitter. I flipped the wrong switch at _just_ the right time and managed to turn on both PA transistors at once. Poof!

19 MAR 2005 - UPS backup battery replaced, transmitter returned to the air at 1110 CST.

Transmitter power output is 400 watts on 166.500 KC.

The modulation sequence is: The ID letters "XSR" are sent once in QRSS30 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.

18 MAR 2005 - Transmitter off the air at 1530 CST because of UPS backup battery failure.

18 FEB 2005 - The WC2XSR/13 transmitter was put back on the air at 1611 CST local time after replacing the failed antenna insulator. Please see web page write-up for further information about the insulator replacement.

Transmitter power output is 400 watts on 166.500 KC.

14 FEB 2005 - The WC2XSR/13 transmitter went off the air this morning at 0450 CST due to an antenna insulator burnout. See web page write-up for further information about the insulator failure.

01 JAN 2005 - The WC2XSR/13 transmitter continues on the air.

Transmitter power output is 400 watts on 166.500 KC.

Reception reports are always welcome.

73, Ralph W5JGV

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