The "Box"
Let's
take a look at the "Box". Everything is mounted in a Motorola equipment
rack. I have 2 fans cut into the box cover to keep everything cool.
They are thermal statically controlled so when it gets warm the fans
kick on. The equipment rack is grounded as well as the PolyPhaser
Lightening arrester in line with the hardline.
The
top piece it the CSI TP-154 Controller. It's the "brains" of the
system. It has the ability to decode 154 simultaneous PL or DPL tones,
which comes out of the commercial world where 1 repeater may serve many
different clients. It can encode all of them as well, but the encoder
is broke! I have a Com-Spec PL encoder installed to get the encode
signal for the repeater. Its not a fancy "talking" controller, but it
works and has good quality audio.
Just below that is the Decibel Products duplexer. This is a notch-style duplexer and provides 60-65 dB of isolation between the transmitter and receiver, allowing us to use the single antenna for transmit and receive! These type of duplexers are typically good to about 50 watts of output power.
Here are some shots of the radio. Pic #3 shows the radio mounted and buttoned up in the rack. Note there are two antenna connections on the radio. As stated before, this radio is duplexed, so it transmits and receives at the same time. The signals are then carried through the 1/4 hardline jumpers to the duplexer.
Pic #7 shows the radio with the cover off. The section with the silver cover is the power amplifier section. Just to the right of that is the pre-selector. The top green board is the transmitter section, and the bottom green board is the receiver.
Pic #8 shows the modification for the antenna connectors. Normally the transmitter and receiver sections both hook up to the yellow transmit/receive switch. When you duplex the radio, you cut the transmit line and the power lines from the switch and then re-attach the transmit line to a new connector installed on the chassis.
Just below that is the Decibel Products duplexer. This is a notch-style duplexer and provides 60-65 dB of isolation between the transmitter and receiver, allowing us to use the single antenna for transmit and receive! These type of duplexers are typically good to about 50 watts of output power.
Here are some shots of the radio. Pic #3 shows the radio mounted and buttoned up in the rack. Note there are two antenna connections on the radio. As stated before, this radio is duplexed, so it transmits and receives at the same time. The signals are then carried through the 1/4 hardline jumpers to the duplexer.
Pic #7 shows the radio with the cover off. The section with the silver cover is the power amplifier section. Just to the right of that is the pre-selector. The top green board is the transmitter section, and the bottom green board is the receiver.
Pic #8 shows the modification for the antenna connectors. Normally the transmitter and receiver sections both hook up to the yellow transmit/receive switch. When you duplex the radio, you cut the transmit line and the power lines from the switch and then re-attach the transmit line to a new connector installed on the chassis.
At
the bottom of the rack is an Astron RS-20A power supply that keeps it
all running. This is actually the second power supply on the system,
and is from my home shack! The first was another RS-20A that was an
E-bay special, but it failed about 6 months into service. I have an
Astron SS-30M sitting on the bench waiting to go in when I have the
chance.
And after a trip up the 7/8" hardline we get to the key ingredient to any repeater- the antenna! The antenna is a Decibel Products DB-420 16 bay folded dipole antenna. It has over 9dB of gain! The base of the antenna is mounted at 150 ft. The antenna itself is 17 ft. long putting the tip at 167 ft in the air! Its HAAT at the base is roughly 130 ft as the Homewood area itself is down in a hole geographically.
So there you have it- The Waldofar Repeater System- 442.375/447.375 PL 114.8. See you on the air!
And after a trip up the 7/8" hardline we get to the key ingredient to any repeater- the antenna! The antenna is a Decibel Products DB-420 16 bay folded dipole antenna. It has over 9dB of gain! The base of the antenna is mounted at 150 ft. The antenna itself is 17 ft. long putting the tip at 167 ft in the air! Its HAAT at the base is roughly 130 ft as the Homewood area itself is down in a hole geographically.
So there you have it- The Waldofar Repeater System- 442.375/447.375 PL 114.8. See you on the air!