| We
are currently testing a 900 MHZ Amateur Radio Repeater located near NC
State University. Since there are no commercial or amateur gear venders
providing equipment specifically made for the ham band, all work had to
be custom built. A lot of gear can be easily hacked to transmit at
902 and 927 but finding one that will receive at 902 is the real trick.
We are using a Motorola Maxtrac 800 MHz radio on the receive side,
modified to receive on 902. A Maxtrac 900 has been hacked to
transmit on 927. We are using a fiberglass 860-950 MHz vertical
with about 10 db of gain at only 550 feet above SL. A commercial duplexer
is providing 100 db of separation at the 25MHz split allowing us to use
a DB products 16dB preamp on the receive side. While replacing the
stock filters in the Maxtrac 800 with 915 filters, the best we could do
was about 1 uv, without the preamp.
Our operator radios of choice that have
been hacked to work in our band are: In our testing we quickly
discovered that 900 exhibits many of the same line-of-sight
characteristics as does UHF with increased multipath during mobile
operations. Most of the time, you are either IN there or you are
not. 2 watt portable coverage is
reported good to Knighdale, Garner, much of Cary, North Raleigh, with diminished
coverage to the west because of the Blue Ridge Road and Harrison Ave.
terrain. Tanner has been able to find some hot spots in Durham with his
10 watt GTX mobile . Once we have a chance
to do further testing, we
may coordinate this to a permanent location.
Photos courtesy KF4MOK. Other Planned 900 Repeaters to watch
out for in the area:
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