At 09:06 AM 06/17/08, you wrote: > > > I am building a large repeater system here in SE Kansas for SkyWarn > > and I am wanting to use the RVS-8 Voter. > > > > Our system uses Motorola Maxtracs for pretty much every aspect > > of our giant 15 county coverage repeater. > > > > Has anyone successfully used Maxtracs with this Voter? If so, > > how did you interface them? > >Rear panel connections throught the 16 pin jack. Like most people. >In the case of Kenwood TKR-820 Repeaters I had to make my own >interface board. > > > The voter has room for up to 8 sattelite receivers. I have a > > bank of UHF Maxtracs all tuned to different frequencies as the > > link receivers. They are all identical, and have 16 pins on the > > rear. I had planned to use PIN 8 COR and PIN 11 audio to feed > > the voter. COR is in ACTIVE HI on the Maxtracs, as such in > > the voter. > >Might be better to build and include a simple logic buffer >circuit. One properly selected and applied fet or transitor >circuit would probably work very nice. > > > The trouble I am having is getting PTT through the voter to be > > consistant, and by this I mean, only light PTT when there is an > > incoming COR signal from one receiver. It seems like the COR > > light on the voter is pulsing all the time, and when a good COR > > is detected, the COR on the voter goes solid and I can see the > > SNR counter go up when I talk through it. > >You probably need to isolate the COR/COS output line (pin 8) with >the simple buffer circuit I mentioned. The description reads like >you're getting some type of logic pin dc interaction between the >radios and the voter. > > > Anyone have any ideas? > >I try not to... > > > > Thanks advance, > > Tyler > > K0FCQ > >Reply back to us if you need specific information about how to >isolate the radio logic output line from the voter. I myself like >active low logic lines where possible. > >cheers, >s.
Note that the LDG voter does NOT use TTL voltages on the COR inputs !!!!! This bit me HARD a few years ago. Each COR input requires a voltage HIGHER than 6.5 volts (up to 20vDC) and going down to ground (less than 1/2 volt) to work properly. Yes, it's in the book ... see <http://www.repeater-builder.com/tech-info/rvs.pdf> Go to page 8, and I quote: >Active HI means that your receiver COR must produce a positive-going >voltage (6.5 to 20 volts) when the squelch is open (receiving a signal) and >a low-going voltage (0.0 to 4.5 volts) when the squelch is closed (no signal). >Active LO means that your receiver COR must provide a low-going >voltage (0.0 to 4.5 volts) when the squelch is open and a high-going >voltage (6.5 to 20 volts) when the squelch is closed. I ended up building an interface board that connected several Maxtrac receivers to an LDG. The actual setup was to program the MaxTracs for active high COR. The signal from each radio fed a 2N2222 transistor base through a 4.7 K resistor. The collectors had 4.7K resistors to +12 as a pullup resistor on each output. The actual radios were 36-42MHz Maxtracs that needed a home... nobody wanted them so they were free.... the 30-36MHz ones end upon 10m, the 42-50MHz ones end up on Red Cross or 6m. The guy that was building the system used a converter from 430-440 and fed a TV splitter. Each output port fed a Maxtrac. He didn't care about the 75ohm mismatch - the signals were strong enough. The converter was set up so that 439Mhz channels showed up on 39Mhz. End of problem. Mike WA6ILQ
