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.
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.
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.
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 a closed autopatch on the system,
although it's not been used in a couple of 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 without having to do that, but who knows what the future
will hold?
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.
In December of 2002 we put a UHF link repeater on-line. It is in the 420
MHz band, and is currently operating in carrier squelch mode pending
coordination by SCRRBA. Modification of the telemetry from the low
band repeater has been implemented to reflect the addition of this link
repeater.
The low band 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 reson the receiver is in carrier
squelch mode, the courtesy beep will be high in pitch (1500 Hz).
Similarly, the link repeater causes telemetry to be sent from the low band
transmitter. Two courtesy beeps will be sent from the low band transmitter
at the conclusion of a transmission occurring on the link repeater input.
As with the low band courtesy beeps, low pitched beeps indicates that the
link repeater receiver is in CTCSS mode, while a high pitched set of beeps
indicates that the link repeater receiver is in carrier squelch mode.
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 19 January 2003
