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W6AQY, Early VHF FM Mountain Top Repeater in Southern California

Created by Paul Signorelli, W0RW on 2022-10-20

 

W6AQY, Early VHF FM Mountain Top Repeater in Southern California

 

 

   The W6AQY repeater was a private repeater located above San Fernando, CA.

   It was located on Contractors Point at about 3500 feet elevation.

   This secret repeater had a code name of "Brian," named after one of my friend’s new son.

   This may be the only repeater with its own name. The site was obtained with a Special Use Permit from the USFS. The repeater was constructed around 1963.

   The repeater electronics consisted of a modified Motorola P33 walkie talkie.


    It had a fully solid state receiver which ran on 6V and drew 30 mA. This was one of the first commercial all transistor receivers produced, but the transmitter had 8 subminiature tubes and a 2E24 (quick heating 2E26) in the final. This gave about 20 watts ERP from it’s 3 Element beam that was pointed toward the center of Los Angeles.

 

 

   Jim, (W6UJX) and his Dad, helped relocate the 30 Foot telephone pole and we dug a trench, and used the trench push up method of installation. The top of the mountain was very rocky and digging the hole was very hard.

 

   The output was on 146.76 MHz with an input of 147.885 MHz The SFV Frequency Coordination Bureau took care of the frequency assignments as there were no other Frequency Coordination groups in the area at that time. There were no standards for repeater offsets and repeaters needed all the offset spread possible to eliminate desensitization.


   It had 15 Germanium transistors and a 1N147 Germanium Diode in the front end. The sensitivity was 1 uV at best. (None of these old walkie talkies, P31, H31, H23, PT400) had transistor pre-amplifiers in the receivers. FET’s weren’t invented or available yet. The batteries lasted about 3 months and then had to be replaced. There were no solar panels then.


  

 

   All repeater maintenance required me to climb the 30-foot telephone pole with spurs and an old leather 'safety' belt. I have since 'hung up my spurs.' (How many of you could ever write that sentence in your epitome), The repeater was contained in a waterproof Motorola truck mount box.


   One of my service calls required me to fabricate a short coax stub to trap out a new UHF TV station that was interfering on my receive frequency from Mt. Wilson. Installing that and retuning the receiver, on site, up on the pole was pretty exciting.


   The receiver had a Private Line decoder. This was to keep all unauthorized users off the repeater. The batteries were very expensive. It took Vern (W6ZJU) about 10 minutes to make a loop tape recording of the PL tone and that allowed him to break into the secret repeater just to say 'Hello."


   The antenna was a side by side 3 element Yagi pointed toward downtown LA. There was one Yagi for receive and one for transmit. The side by side arrangement gave needed isolation between the receiver and transmitter. The repeater covered all of Southern California and I recall using it from San Diego.

 

 

   Fortunately the repeater was removed for servicing right before someone cut the pole down with a chain saw in about 1969. Where is the W6AQY repeater now? After serving SoCal it moved to Colorado and did some time as WR0ACR. Now it is in stand by service high in the Colorado Rockies. It has been in service for over 50 years and still working.

 

Paul, w0rw

 

W0RW2022-10-31
Re: W6AQY, Early VHF FM Mountain Top Repeater in Southern California
Thanks for the info about CORA, Darrell.
There is one more SoCal repeater that you can read about.
See the 'K6MYK' repeater in QST, March 2004...p52, written by Bill Pasternak, WA6ITF.
Paul w0rw
Reply to a comment by : K7LZR on 2022-10-29

Very good story and of historical significance. Thanks for sharing. Here in Southern Oregon, there was also a repeater which had a name. Her name was Cora, so named because it was an acronym for Computer Operated Repeater Application. But her users all knew her simply as Cora. Cora was one of the earliest repeaters to be totally controlled by an off-the-shelf computer. Cora existed for several years in the early 1980s the first time, on 2m with the frequency pair 147.38/98 and later 147.20/80. The callsign then was KA7BTV/R. Cora was located for a bit on Pelican Butte with very wide coverage, and then later on Hamaker Mountain. Cora went QRT in 1989 and was not heard from again for a very long time. Many years passed, many things changed. In 2004, a new Cora was designed and built with updated technology. This new Cora was relocated to the 70cm band and remote bases for 2m, 6m, and 10m FM were added. Echolink was also included. The new Cora was kept at low-level elevation due to the remote bases but still had good coverage for a low-level machine. Cora II went QRT for good in 2015, after 11 active years. Again, thanks for sharing the W6AQY story. That is such a great piece of ham radio history. I'd love to see more of these stories, and in particular more about the early ones of Southern California.
K7LZR2022-10-29
W6AQY, Early VHF FM Mountain Top Repeater in Southern California
Very good story and of historical significance. Thanks for sharing.

Here in Southern Oregon, there was also a repeater which had a name. Her name was Cora, so named because it was an acronym for Computer Operated Repeater Application. But her users all knew her simply as Cora. Cora was one of the earliest repeaters to be totally controlled by an off-the-shelf computer.

Cora existed for several years in the early 1980s the first time, on 2m with the frequency pair 147.38/98 and later 147.20/80. The callsign then was KA7BTV/R. Cora was located for a bit on Pelican Butte with very wide coverage, and then later on Hamaker Mountain. Cora went QRT in 1989 and was not heard from again for a very long time.

Many years passed, many things changed.

In 2004, a new Cora was designed and built with updated technology. This new Cora was relocated to the 70cm band and remote bases for 2m, 6m, and 10m FM were added. Echolink was also included. The new Cora was kept at low-level elevation due to the remote bases but still had good coverage for a low-level machine.

Cora II went QRT for good in 2015, after 11 active years.

Again, thanks for sharing the W6AQY story. That is such a great piece of ham radio history. I'd love to see more of these stories, and in particular more about the early ones of Southern California.

KD6VXI2022-10-21
W6AQY, Early VHF FM Mountain Top Repeater in Southern California
That's a really cool story of this repeater, Paul.

Colorado Springs and the immediate area are so beautiful. Can't blame you for wanting to do pedestrian mobile.

73

--Shane
WP2ASS / ex KD6VXI