This
picture on the right is the finished product, complete with homebrew
duplexers on top. The brown duplexers were originally VHF cavities
designed for 1.5 mhz commercial split, and were inappropriate for 2
meter amateur use. The "guts" were removed, new coupling loops and
harness built, and away they went. The 3 silver cavities (two are behind
the others) were scratch built from aluminum irrigation pipe, using
copper pipe for the stubs and copper plate for the end caps. They were
originally built as bandpass/band reject cavities from the ARRL
handbook, but were later modified for notch only to minimize losses. The
repeater was actually a telephone remoted RCA series 1000 transmitter
used by the local power and light company to control hot water heaters.
The
photo to the left is the repeater with it's cabinet open. Starting from
the bottom, there's a Motorola Micor for a UHF remote link, a 30 amp DC
supply for the remotes, power distribution panel, telephone remote
interface, RCA 1000 RX module, ARR GaAsFet RX preamp, voltage regulation
rack, exciter and force cooled PA, and a homebrew "brute force"
force-cooled 13 vdc regulator rack. The controller is a MCC RC-1000 with
customized firmware. The PA is from a 100 watt VHF GE Mastr II mobile.
Both
the link and the primary rx's are tone decode for interference control
using Selectone decoders. A pl of 88.5 is required for access, and this
pl is also re-encoded on it's output signal during COS activity for
linking purposes.
This
repeater's primary coverage area was Wilson County, and it was linked
full-time to 442.400+ KD4WJD in Zebulon, NC (about 30 miles W) and
147.39+ PL 88.5 WB4IUY in Clayton, NC (about 35 miles SSW).
This
next photo is of my oldest son, Chris KF4DBX, installing a copy of the
WA4UQC station license to the repeater cabinet. Along with several
others, Chris has spent many hours at this repeater site helping with
upgrades.
The
photo below is a shot from the 147.300's link antenna perch at about
100 feet, looking at it's link antennas awaiting signals to relay. It
was taken at nightfall looking into a beautiful NC sunset. In the daytime,
the view is quite nice from this site. The large antenna on top is
pointed to 147.39 in Clayton, while the smaller antenna below is pointed
towards Zebulon.