KS3R / R
Revised 3/5/14
Click on the update icon for the current status of this repeater. Notice: The original SHARC-1 Repeater has been replaced with a
new repeater purchased by the club. We are waiting for better weather conditions to install the new antenna on the tower for the repeater. The original antenna installed in 1986 has developed problems. In the interim, we are running the repeater on a ground level antenna and at a lower power to minimize RF densense back into the repeater's receiver.
Pictures of the new SHARC-1 Repeater may be viewed here:
The repeater consisted of a GE Progress Line, 50W transmitter/receiver (all tube type), with a very basic home-brew controller that only provided tail/timeout and courtesy tone features. The repeater was housed in a 4' communications rack, originally turquoise in color, but I later painted it black and gray (shown below). A TRS-80 was used to provide random CW identification. The repeater was operated with split receive and transmit antennas that were horizontally isolated. The repeater was eventually coordinated on the frequency of 145.390 MHz, and in 1983, a Sinclair Radio Laboratories duplexer was purchased, eliminating the need for split antennas. The basic controller was revised and redesigned with plug in cards that expanded the repeater's capabilities. A new antenna was purchased for the system, which consisted of an AEA Isopole, and later 50 feet of 1/2" hardline was purchased to replaced the original RG-8 coax. | 
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 GE Progress Line 50W Transmitter & Power Supply |  GE Progress Line 50W Transmitter & Power Supply |
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In 1984, Jeff - KB3W had taken a job in Utah, and the repeater was down for almost a year until he had returned. During that time we lost our frequency to Johnstown and we decided to put the system back on the air. The repeater was recoordinated on the frequency of 145.130 MHz, the frequency it remains on today. In 1986, Jeff decided to build another repeater, and to eliminate any interference problems that might arise between the two machines, we agreed to move the original repeater from McMurray to its present site in Bridgeville. Ken - WB3JOB, graciously let me put the machine in his ham shack, and put the repeater antenna at the top of his 60' tower. Jeff continued to work on the new machine and later received coordination on the frequency of 147.345 MHz. Jeff's new machine consisted of an RCA 500 Series 100W transmitter/receiver and an TX/RX brand duplexer.
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Jeff designed a controller program using a Commodore VIC-20, and some various external circuits to control the new machine. I scrambled off and wrote my own program using a Commodore C64, and expanded the controller (nicknamed "Cylon") on my machine. In 1986, I purchased a new Hustler G7-144, 7dB colinear antenna to replace the AEA Isopole antenna that had been mounted previously on the tower.
Later in 1986, I had designed a battery backup system to retain the C64's memory in case of a power failure. The backup system produced 120 VAC from a 12V car battery and kept the battery charged at all times. The computer was powered from this source at all times, and only used power from an AC outlet to keep the battery fully charged. In 1987, I purchased a spare RCA 500 Series 110W transmitter/receiver from Jeff - KB3W and in 1988, I replaced the GE Progress Line tube gear with the RCA solid state gear. Click [ here ] to see a picture of the RCA repeater. I also built and programmed an auto-boot cartridge that now replaces the battery backup system. If a power failure occurs, the computer boots and executes the cartridge when the power is restored. |
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The repeater today, is quite different than what was first put on the air in 1979. The controller is quite dependable, and provides over 50 commands that can easily be changed or expanded. The RCA transmitter/receiver have proven to be dependable as well, and rarely needs maintenance. Jeff - KB3W eventually sold his repeater to Ralph - WB3AZL, and took a job working for Kodak in New York. He has since built another repeater which is currently in operation in New York. Jeff has changed jobs several times, having worked for Hewlett Packard & Sony, but now lives in California.
Update: The 147.345 repeater has been off the air for quite some time. In April of 2004, The Western Pennsylvania Repeater Council (WPRC) has terminated it's coordination.....SIGH... R.I.P. 147.345... |
