ScanDaBands said:
Here's a present setup I saw I'm curious about:
Current VHF system setup this way,
GE Master III Repeater with this order. 911 center has a computer that keys the
"mic" and sends the signal to a computer then sends the signal to Voters then
through phone lines to the GE Master III.
They also have a UHF system with a GE Master III BUT it's setup this way , same
911 com center , sends the same to computer here's where it changes , goes to
controller radios which sends via antenna (rf instead of phone lines) to the
repeater site where they have the voters and out the repeater.
ok here's where the Kenwood comes into play , the TKR-750 can you run the
through doing the phone line thing ? Let me add the VHF system is through two of
the phone line wires NOT four. So here's what I "overheard" on the situation.
They can get it to work BUT the dispatch (911 center) will not key the repeater
, can the Kenwood be made to work on a two wire phone line?
Curiosity is "killig the cat" here.
The Kenwood can be controlled as a remote base through the accessory connector, but to work on a phone line you'd need an external remote control that can interface to the radio and the phone line. I'm familiar with the repeater but not familiar with using it as a base/repeater over a phone line.
I also recommend staying entirely away from the TKR-750 (VHF) and the TKR-850 (UHF) line of Kenwood repeaters. The Power Amp (PA) in these are CRAP and aren't reliable. The rated power output is NOT for continuous duty. The TKR-750 (VHF) is rated at 50W and the TKR-850 is rated at 40W. The the power needs to be turned down for them to be reliable in the field. 25W is all they'll safely do continuously. The 850 in particular has had such a high failure rate in the field that Kenwood came out with a version 2 and will replace the PA in older version 1 units with an updated PA assembly, even on units which are out of warranty. The field failure rate with 850 version 1 repeaters has been close to 100%!
A friend of mine owns a radio shop and is a Kenwood and Icom dealer and has had several TKR-750 and TKR-850 repeaters in service as community repeaters. The TKR-850's have had a 100% failure rate and a couple of TKR-750s have also failed. He's since replaced all of them with Icom FR3000 (VHF) and FR4000 (UHF) repeaters and they've been 100% rock-solid bulletproof reliable. I bought one of his problematic TKR-850 repeaters dirt cheap after it came back from Kenwood. I set it up on GMRS and it promptly *died* right on the bench before I could put it into service. It went back to Kenwood AGAIN for repair. I got it back (free of charge) and all was well for a while before it died AGAIN. I fixed it myself this time and it ran for a couple of years before it died AGAIN. I recently fixed it AGAIN but this time I investigated the failure and I think I've fixed it for good this time. I found the driver FET feeding the final FET has a nasty habit of unsoldering itself from the PCB. I found one of the pins relied upon for heatsinking to the board wasn't soldered due to soldermask getting in the way. I scraped away soldermask and resoldered this part properly so it should run a lot cooler. I also ended up re-soldering the ENTIRE PA board because of a couple of cold solder joints and that seems to have fixed it. So far I haven't been able to kill it with it continuously transmitting into a dummy load at high power. If I have any more problems with it, the PA board goes back to Kenwood to get it replaced with the version 2 PA board.
The TKR-750 and TKR-850 repeaters come in a nice package but unfortunately that's about where it ends. I speak from experience when I say STAY AWAY from these repeaters. They work great when they work but I don't trust the PA in them to be reliable. Seriously STAY AWAY from these repeaters in any mission-critical public safety application. Go with an Icom FR3000 VHF repeater instead.
Good luck.
