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History of the Tesuque Peak Repeater
Article by Alan Hill, N5BGC |
Let's look at a little history of our two meter radio system
on Tesuque Peak. It was installed about 1972 by several local
hams. The repeater was bought from the State of New Mexico
by the club. It was a Motorola radio that was designed to
be a repeater when it was built. This, of course, gave it
an advantage since it did not have to be modified. A CW id
was added to fulfill FCC requirements. There were no controls
with the controller.
It was first installed in a Quonset hut at the south end
of the mountain top. The state used this building to house
the standby generator used for the state radio equipment.
The coax ran to the top of a tower owned by Motorola for use
by commercial entities on the peak. The tower was about 60
feet tall and we were right at the top. This provided us very
good coverage at the time. Of course, there were only about
30-40 different transmitters on the mountain top.
A few years later, that tower was replaced with a new one
and ownership changed. At that time, we lost our free use
of the tower. So we decided to take the antenna and put it
right outside the door on the Quonset hut building. It was
at a height above ground of about 8 feet and, of course, there
was only about 10 feet of feedline. The system worked well
there but there were beginning to be dead spots in the coverage.
When the state rebuilt their site in about 1987, that building
was removed and the radio was installed in the state building
were we are now. We are very lucky in that there has been
a Santa Fe ARC member working for the state Radio Communications
group since the first repeater was installed. The state also
installed a 60 foot self supported tower. We had to use what
space that was available on the tower. At first we ended up
on the south face. About this time, the population of radios
on the site began increasing. It was about 100 by then.
At about this time, we replaced the Motorola radio with a
commercial GE. It was called a Master. It had a transistorized
receiver and transistorized exciter and a tube multiplier,
driver and final. This radio was interfaced with a UHF radio
that was used by the autopatch. The autopatch was located
at AG5S Alden Oyer's house in Santa Fe. This arrangement worked
when the State Police and Los Alamos Police department were
not transmitting. These frequencies plus the second harmonic
of our own transmitter were killing us. I will write up an
article describing how that happened. It is not a major problem
now.
About 3 years ago, the technical committee installed a CTCSS
tone on the receiver to cut down on the constant intermodulation
interference. This is very necessary for operation on the
mountain top with in excess of 150 transmitters.
About 2 years ago, we moved the antenna to a slightly higher
location on the northwest face of the tower. That location
plus better mounting hardware allowed the antenna to work
better.
About 3 years ago the club bought several GE mobile radios
that were removed from commercial service. These radios are
very close to the Master 2 repeaters that GE just a few years
ago quit making for the two way industry. They are crystal
controlled with 1 to 8 channel versions. The channels are
derived simply by switching crystals. The technology was state
of the art for the time period. Since they were removed from
commercial service, the range for the frequency tuning on
the front end is from 150.8 to 174 MHz. Since we have to retune
the front end to 146.22 MHz, the "Q" of the tuning
circuits is compromised. The radios will tune this far, but
the quality is not there.
Of the 3 radios that we bought, all three of them experienced
tuning problems. When the technical committee went to the
site, we retuned the coils and capacitors and get the receiver
back within specs. A few months later, the problem reoccurs
and we have problems with getting a weak signal through the
receiver front end.
The technical committee has another radio in place for the
site. It also is a GE and this one has the correct front end.
It covers from 132 to 150.8 MHz. That puts 148.22 MHz well
within the designed bandpass. This is the repeater that is
now in service. It works well except for a few minor problems
that occur now and then.
Overall the 146.820 repeater has been in place for about
30 years with various electronics. We have done this without
breaking the club budget. Do we need a new more modern repeater?
It would sure be nice, but the $1000 price tag is not in the
club budget. Fortunately, the technical committee enjoys going
to the top of the mountain.
Alan Hill, N5BGC
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