Portable 70cm repeater 440.750 or 440.800 MHz

This repeater is extremely portable and light and is fully featured. This repeater is built out of two Motorola handhelds (GP300 series) and is on the two SERA approved itinerant UHF pairs. The duplexer actually tuned up OK and allowed for both pairs.

Last year at Dayton, David and I spotted the group from the Miami Valley RF group, and they had a couple of these repeaters for sale. They are built by Glenn, W8AK. David and I thought we should come on home and try to whip up the same style repeater.

After talking to Glen at the hamfest and then doing the math, we realized that we probably couldn’t build it as cheap as he could, and his work was of the quality that we look for. It’s possible to build this with a simple controller, or Glenn also had put one together with a NHRC controller, which can add a load of features. The NHRC in ours will do voice ID, CW ID, DTMF control, time out timer, and more.

The two portables make up the tx/rx section. The radios typically require a 7.5 volt battery to run, but you can see the small voltage regulator mounted on the panel that adjusts the input to the radios to approximately 8 volts. The duplexer is a typical can style duplexer found in many UHF repeater operations.

Our testing showed that the entire package could be run from 13.8v with 120ma sitting idle, and 2.02 amps on transmit/receive. Power out of the TX radio was 4.5 watts and out of the duplexer 3.5 watts. The entire operation can run off of a gel cell for quite some time, and the panel is actually a standard 19 inch rack mount panel.

So whats next? Perhaps we will modify the panel it is mounted on, to place it all in a box for even more portability and ease of operation.

Here are some close ups of the radio, and the controller area.

W8AKs group runs a website at Miami Valley RF Group
NHRC controllers can be seen at the NHRC Website

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