The KB6MIP/R Repeater Page

The History of the KB6MIP Repeater

My repeater has been around for a long time.
It has a colorful history covering quite a few sites.
Through all it's variations one thing has remained constant, it has been an open machine.



The Fullerton Days

KB6MIP/R first went on the air in 1988 in the city of Fullerton at the Hewlett Packard facility I worked at, northwest of the interchange of the 57 and 91 freeways (GPS users can find the original site, long since vacated by Hewlett Packard, at 33-51-25N, 117-54-12W). It's first channel pair was 52.660 in, 52.060 out. It was coordinated about a year later on the pair 52.100 in, 52.900 out. The original repeater was a duplexed General Electric MASTR Executive II 100 watt low band transceiver. The original "controller" was a home-brew CWID / COR assembly made for our group by Ken, KB6MKX. Ken also made the two j-pole antennas we used, which were horizontally separated by about 150 feet on the rooftop of our two story office building. We had no filters of any type in the original system. Needless to say it's performance was less than stellar, but we got by just the same.

A group of hams at the Hewlett Packard facility at that time formed a club called the Hewlett Packard Amateur Radio Association. The club sponsored and supported the repeater activities at the site, and also put together an HF station with a multi-band cubical quad beam antenna and a 2kW transmitter. In 1989 we obtained the WaCom duplexer which is still in use today on the KB6MIP repeater. At the same time we upgraded our antenna system with a Ringo Ranger antenna for six meters and an S-Com 5K controller. While it has had a couple of software upgrades since then, the controller we use today in Yorba Linda was originally put in service at the Fullerton site in 1990.

Sometime around May 1990, in conjunction with a general meeting of the six meter band trustees called by SCRRBA (the coordinating body for the band), my input channel frequency changed from 52.100 MHz to it's present 52.400 MHz. At about this same time, we added a local UHF repeater to the Fullerton system on 447.125 MHz. This UHF repeater was built up from a duplexed General Electric MASTR II mobile transceiver and used a duplexer and antenna donated by one of the club members. It was coordinated as a closed repeater due to bandplan considerations imposed by the coordinating body, and also because it was a "secondary occupant" of the channel pair, the primary coordination belonging to a closed system on Palos Verdes. Even with these considerations, I treated my 447.125 repeater as an open, "home town" repeater most of the time. It's coverage area was limited to north- eastern Orange County, for the most part. These repeaters remained in service in Fullerton until I left HP in January 1993.

Sadly, for all the time the repeater was being built, deployed, and upgraded at the Hewlett Packard site, these seem to be the only images surviving of the entire ordeal there. These images were originally 35mm color slides, taken with my Pentax SP1000 using RGB ASA100 film and a standard f2.8 lens. My apologies for the poor image quality, the slides did not fare well in storage. If I come by more images of the HP days I will be sure to add them to the story.



Johnstone Peak

In May 1993, 52.900 moved to Johnstone Peak, 3000 feet above San Dimas, and remained there for about a year and a half. The 447.125 UHF repeater was de-commissioned prior to this move, and has not been in service since then. Around the end of summer 1994 the site ownership of the vault I occupied at Johnstone Peak changed, and the new owner began closing deals with commercial air-time vendors. As a result of this, I (along with all other amateur interests in the vault at that time) was asked to leave.

Originally deployed with an old Cushcraft Ringo Ranger antenna, the repeater's performance was marginal at best. In July of 1993 an upgrade was made at the site which involved the addition of a Kreco CP-30A antenna, and a two channel remote base on two-meters was added (146.520 and 146.550 simplex). The antenna made all the difference in the world in repeater performance, and the remote base allowed users with two meter radios to join in the fun. The remote was built on a General Electric MASTR Executive II VEU chassis. See my Tech Page for documentation on how the remote was built.

These VEUs were originally built as low power one-channel mobile transceivers for the California Highway Patrol. CHP called them Vehicular Extender Units, and they were designed to act in conjunction with the VHF low band mobile radios in the cruisers, allowing officers to use small VHF high band handy talkies while outside of their cruisers to maintain communications with their dispatch.



The Whittier Site

52.900 then relocated to Whittier near the corner of Painter and Hadley on an office building. I used this site to occupy the channel while negotiating for a new "high site". During the time the repeater was located here the hardware was converted from the GE equipment to the currently employed Motorola MICOR station.

While performing quite admirably as a small-town repeater, the Whittier site had very limited coverage, due to it's surface elevation of around 800 feet with terrain rising to the north and east to about 1200 feet or more. Another debilitating factor was the close proximity of some poorly installed CATV trunks. It did see downtown LA in a reasonable manner, though. The two-meter remote continued to serve at this location, but was removed from service when the repeater was moved to it's next site, Sunset Ridge.



Sunset Ridge

In August 1996 the 52.900 repeater went up to a high site at Sunset Ridge, which is north of the city of Upland at 5200 feet MSL. A UHF link to the 52.800 Sierra Peak repeater was put on line, but the system became very noisy. Then ice and wind destroyed the link antenna and damaged the repeater antenna in the storms of January 1997. After that the link was removed from service pending a re-engineering by me, and was never re-installed.

As can be seen from the photograph, Sunset Ridge is a very busy place in terms of RF systems. Intermodulation interference and other noise issues began to plague the repeater here, and conditions gradually worsened as the months went by. Intermodulation panels are difficult to come by in amateur low band, and while we tried all kinds of other tricks with additional filtering, the problem eventually escalated to the point where we were visiting the site numerous times a month. This became somewhat impractical, as access requires a four wheel drive vehicle whenever the weather isn't perfect. Finally it came to the point where I was spending more money in fuel each month to make service calls there than I was in site rental, and the decision was made to move from Sunset. The repeater was removed in September of 1998.

For a while the repeater spent some time in my shop being "wrung out" and upgraded with some new interface hardware and system components. Finally, in May of 1999, the repeater was deployed in Yorba Linda.



Yorba Linda and The Current System Configuration

The KB6MIP repeater is located on a ridge above and to the north of the city of Yorba Linda, California. Surface elevation is about 810 feet MSL. From the site on a clear day one can see Catalina Island, the Port of Long Beach, and the south bay area, as well as Newport Beach and all of Orange County west of the 55 Freeway. On a really clear day one can just make out San Clement Island.

The repeater is a Motorola MICOR base station controlled by an S-Com 7K controller. ERP is about 70 watts. The antenna system is mounted on a twenty foot Rohn 25G tower, using Times Microwave LMR-900 coaxial cable for the feed. We have a building entry panel with a PolyPhaser IS-B50 series coaxial protector for EMP protection, as well as a cable grounding kit on the feed at the top of the tower. The antenna itself is a Kreco CP-30A. We use a four-cavity WaCom (now owned by TX/RX Systems) model WP-609 duplexer in the antenna system, as well as an eight bay DCI helical filter. We have standby generators for any Edison power interruptions which may occur, and the site is climate controlled. There is an autopatch on the system, although it's not been used for many years. The advent of cheap cellular and PCS phones has sort of made autopatches obsolete

The repeater is sponsored after a fashion by my employer, The Metropolitan Water District of Southern California (MWD). As a result of this sponsorship, Metropolitan may request access to and priority use of our system during times of disaster to facilitate their emergency operations. This means that in the event of a disaster which affects MWD's facilities in the Orange County area it is possible the repeater may be temporarily closed for use as a backup communications channel by licensed MWD personnel. That situation (emergency operations on the repeater) hasn't arisen yet. We survived Y2K and a couple of earthquakes without having to do that, but have utilized the repeater in some emergency preparedness drills and tests.

The Yorba Linda repeater is an open repeater. I encourage folks to use it as often as possible, it is here for the amateur community to enjoy. The repeater is typically run in CTCSS mode (Continuous Tone Coded Squelch System) using an access tone of 82.5 Hz. This is done to help us cope with a minor noise problem at our site, caused by a combination of industrial equipment and a near by paging facility. If your six meter radio has CTCSS decode capability, you can use that with our system, as we also encode 82.5 Hz tone in the transmitted signal regardless of what the receiver decoder is set up to do.

\Historically I have preferred to run my repeaters in carrier squelch, but noise considerations have pretty much caused me to shift to full time CTCSS operation. On rare occasions when I am working with or testing the system I may disable the CTCSS decoder at the repeater, making the system a true "carrier squelch" repeater. The repeater transmits a single courtesy beep at the end of each received transmission on the low band input. This single beep will be in one of two formats, depending on the status of the low band receiver. If the receiver is in CTCSS mode (as it normally is), the courtesy beep will be low in pitch (750 Hz). If for some reason the receiver is in carrier squelch mode, the courtesy beep will be high in pitch (1500 Hz).

There are quite a few radio systems at the Yorba Linda location, most of them MWD company systems, roughly half of them in low band, one 900 MHz data radio, and the balance in UHF. Our communications center also has an amateur HF rig (160 meters through ten meters, plus all modes on six meters, two meters, and 440 MHz UHF in one box), plus additional amateur FM transceivers in six meters, two meters, and 440 MHz UHF. We use these transceivers as backup communications in emergency response activities. There is also a GMRS repeater at the site.

Thanks for visiting the Yorba Linda repeater and our web page. As this web site evolves we will be adding photos of equipment and perhaps users as well, so check back with us now and again. Join us on the air whenever you can, and bring along a friend!

E-mail the trustee.

Page last updated 31 May 2009