ATN Yearly Meeting

Our annual meeting will be February 17, 1996 (Saturday) at 12:00. 250 Turner Ave., Ontario, CA. (Guasti Village area). It's in the Television Center for Caritsa Telecommunication located behind the Catholic church, next to the 130 ft. tower.

All ATVers are welcome to attend the meeting. Talk in on ATV 2 meter frequency 146.43 simplex.

Come early and go to the Devry swap meet in Pomona and then breakfast at Baker Sq. We always have a large group of ATVers show up for breakfast after the swap meet every month.

If you have any questions call Mike WA6SVT.

Repeater Information

System Updates

Santiago Peak

Several changes and enhancements have been made this last year. Mike, KC6CCC has donated a 2417 MHz link receiver module and an FM IF housed in one of his receiver boxes. Thank You Mike! I mounted each receiver in its own 5 1/4" relay rack panel donated by Greg, N6TDZ. Thanks Greg. I added a signal strength meter with modification to the receiver supplied by Mike, KC6CCC to add this feature. On January 12 Dave, KA6DPS and John, KA6HXX and I went to Santiago to install them and service the cooling fans for the room, Dave also documented the outer loft area. Thanks Dave and John. Two months ago Mark, WB6AJC was at Santiago and removed the reflector on the 2441 MHz antenna and moved the antenna and converter to the top of the tower to get maximum results and minimum QRM from the new paging transmitter antennas that were mounted near the old antenna position. Mark has made several trips to Santiago, Blueridge and Breckenridge to service and upgrade the network. Thank you for your valued efforts.

Spectrum International has informed me that they plan to ship a new designed low loss VSB filter in late January and we will be able to evaluate it on Santiago Peak. If we like the results we can get it at a special price; details at the meeting. We have received a notice from the site manager that the other Amateur systems will be moving to the loft to make room for the commercial systems as the floor is full in the main room. We built the loft about 4 years ago and it is in two parts: the inner loft is sectioned off and is exclusive to ATN and has a locked door, the outer loft is open. Due to more ham systems over the years installed in the building we may have to squeeze our operation down and remove our monitors etc. to make room for several systems in our room. I hope we can fit the other ham systems into the existing outer loft or get approval to extend the loft, more on this at the meeting.

Mike, KC6CCC and Al, KF6YM has set up a temporary link near Al's QTH to receive the output of Blueridge and microwave it to Santiago. Thank you Al and Mike for all your wonderful efforts. The permanent link will be transmitted from Blueridge on 2417 and beam bender at WA6SVT QTH to relay this signal to Santiago (split site between my QTH and my neighbor's QTH). Also at this location will be a beam bender for 1253.25 the Santiago output to Blueridge and the Victorville area. Mike, WA6SVT donated a complete 1253 MHz receiver and VSB filter and it is installed at Blueridge. The beam Bender antennas are also installed at WA6SVT's QTH.

Kevin, KA6IJA donated a beautiful rack mounted cabinet for the computer. Thank you Kevin. Curt, N6TWB is planning to add the interface for some telemetry of the controller and programming upgrade. Thank you in advance for your upcoming efforts. I have prepared the cabinet to house the computer and will build a DC power supply to give uninterrupted power to the computer from the battery bank on site.

The link transmitter from Oat Mt. is at my QTH awaiting a 5 watt amplifier to improve the link reliability from Oat. Sorry for the delay but the high altitude sites had to be serviced before we got snowed out. Well that's about it for the Santiago report and I want to again thank the above mentioned ATN members and also all of you who have helped over the years to make ATN the best ATV system around!

New Repeater

The old WA6SVT Santiago repeater equipment just could not be retired to the mothballs. It is now on 1289.25 out and 434 input with the call of WA6SVT at Little San Gorgonial Mt. at 9000 + feet. It is above Beaumont Ca. and has coverage in the Palm Springs, Salton Sea, Imperial Valley, Inland Empire, some of the high desert, west San Diego County, and LA-Orange Basin. The repeater can be turned off if necessary if a Public service portable repeater needs to temporarily use the frequency for a disaster. After the links are finished to our existing network this site will probably be linked into the network. For now when Santiago is busy with 2.4 GHz QSO's you can swing over on 434 MHz and have a second QSO going without cross QRM or want to explore new coverage areas. More on this at the meeting.

Palomar Mountain

Call sign W6NWG, Palomar Amateur Radio club call. Current Trustee of club is Ron, WI6B changing to Mike, AB6QT as soon as paper work is returned from the FCC.

Inputs: 919.25 VSB (user switchable) Touch Tone 268 on intercom frequency for AM Input.

915.0 FM +/- 6 MHz Touch Tone "C" for FM input. Audio Subcarrier 5.8 MHz.

2430 MHz FM +/-6 MHz Audio Subcarrier 5.8 MHz. Note this is used for incoming link from Santiago Peak, NASA Select, and is being used as a user input when link is not on until a 2441.5 user input is installed.

146.430 MHz intercom coordination frequency PL 79.7. Note: Picture ID is activated and audio is retransmitted when intercom is brought up for testing purposes.

Output: 1241.25 VSB Power-Out 100 Watts PEP. Antenna Gain 10 dBd.

Location: The south slope of Palomar Mountain at the 5,600 foot level. The Palomar Amateur Radio Club owns a 1/3 acre site with three buildings, 5600 AHr. battery backup power system, an 80 foot tower, and operates 1-6M, 5-2M, 2-1.25M, and 3-70cm repeater/nodes from this site besides the ATV repeater.

The current ATV incoming link is on Murray Ridge at Sibyl's QTH (W6GIC).

We have not decided on a final link site, but most of the equipment has been purchased for completing a two way link to Santiago Peak. We lost the first site when a club member moved back to San Diego. A replacement site has yet to be selected and the link tower is being stored on the Palomar Club property. More information will be available after our repeater technical meeting this month.

Breckenridge Repeater - Trustee Report, WQ6I

This repeater is the northern most link in the ATN network, located in the Greenhorn ranger district of the Sequoia Forest. The input in 434 MHz (AM) and the output is 1277.25 MHz (VSB).

Currently covering Kern county, this repeater's importance to ATN is a link to northern California. The plans call for linking to Mt. Oso then to Mt. Diablo in the Bay area. In November, WA6SVT, Doug Law, and I made a trip to the site, installed a new eprom with WQ6I on it, added a larger dish antenna aimed back to Blueridge which gave a great picture. We did not finish implementing the improvements planned...it was very cold up there and by 11:00 pm we had all we could take. I have delivered to WA6SVT a 1/4db filter (PSF 1280), a VOR 2 board, ATVR 12 IF receiver xtal, coax and a Conifer 25T-2400 dish to be aimed at Mt. Oso, 187 miles away.

If the ATN network decides to maintain this site...1996 should be the year that we see the whole state of California...if not, we have state of the art equipment that can be used at another site.

Technical Notes

Tracking 900 MHz Radar

When I first got interested in ATV in the summer of 1994 I had two ATV repeaters to choose from. The San Diego Mt. Palomar ATV repeater (1241.25) or the Santiago Peak ATV repeater (1253.25). I first tried Mt. Palomar but a hill blocked my view of this repeater. So, I decided to try for the further (60 miles from my QTH) Santiago Peak repeater. It turns out I had a clear shot to this repeater so this is the one that I have spent my time building a station around.

In the summer of 95 after making numerous improvements to my receive setup I was able to finally get a good receive picture from Mt. Palomar. It was at this time that I started to watch both machines from time to time. I then started to talk to some of the guys on the Mt. Palomar repeater and found out that one of the biggest problems with this machine is the interference problems on 900 MHz. The biggest source and most disruptive was one source that would come on and stay on for days at a time. It looked as though it was some kind of radar. I decided to see if I could determine what and were this source of interference was coming from. After talking with the guys on the air they felt that it must come from ship based radar as the direction would be different at different times. Also, I tuned to the frequency of the radar with my ICOM R-7000 and listened. I could determine by watching the S meter peak, that the scan rate of the radar was about 5 seconds. Also, the ATV pictures would have 2 consecutive scan lines blanked out, so we know the pulse width of the radar would have to be about 130 microseconds.

Working for an aerospace defense company I wondered if there was any information that my company might have that would help locate different radars. I headed for the company library. The most known source of this kind of information would be "Jane's" which lists just about every kind of military hardware. Unfortunately my company does not subscribe to this. But, my company does subscribe to a clipping service. A clipping service will send you information on any topics you choose. They subscribe to almost every magazine, trade journal, newspaper, and company annual reports. They then sort through this information send you the information you are interested in. They also compile books of data on selected topics. One such book that we had was about currently in production military receivers and transmitters, including radars. I searched through this book from a company called Military Electronics Briefing looking for the data we already new about. I found a match. It was listed as an AN/SPS-49 Surface Ship Air Search Radar. It also contained data about the radar. Such as:

Band: L

Frequency: 851-942 MHz

Peak Power: 280 kW

PRF: 280, 800, 1000 pps

Pulse width: 125 microsecond

Range: 250 nm

Scan Rate: 6, 12 rpm

Manufacturer: Raytheon Co.

Even though I was pretty certain I had found the culprit, I decided to try another independent route. I posted a message on the internet to see if anyone else knew of any radars at 900 MHz. Most replies I received back told me that our most likely source of interference was from a new car alarm system. But we had already eliminated this. We knew it was a radar. But I did receive one response from a gentlemen who said that most of the responses I was getting were incorrect. He correctly identified the source as an SPS-49 radar. He also went on to say the Southern California probably has the largest concentration of them in the world.

From there I turned over the information I had received to Art, KC6UQH, the president of the Palomar Amateur radio club. He has in turn contacted the Navy to see what can be done in regards to peaceful coexistence. But, if you look at a spectrum chart the frequency range that this radar operates in is filling up with pagers and cellular phones so 900 MHz is about the only place left. And the radar is not going away, so only time will tell if this will be an on-going problem for 900 MHz users here in San Diego and at port city locations.

Membership Information

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John Gibson

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Ontario, CA 91762