Ham Radio - Teardown of a Kenwood commercial UHF repeater

[@W5KVV]

We are currently using the VHF variant, the TKR-720. Given to us by a local public safety organization. I brought it down to 2 meters and it's an excellent performer. Squelch opens at .2uV. 40 watts out with a good fan on the heat sink. Excellent piece of equipment.

[@RadioHamGuy]

That was fun to see, I remember working on one of those many years ago when I worked as a two way tech for a shop. From what I remember, that was a very nice repeater, all self contained with the duplexer and everything needed in a small package and easy to set up and use. I am thinking that it was a UHF model only with built in duplexer since the VHF duplexer might be too large to put into the package but I don't remember for sure, maybe they did have a VHF one also. 73

[@k4sbb829]

the ham pl tones and the commercial pl tones are the same now the digital voice pl tones are a totally different critter

[@loughkb]

There's something different about it on this unit. The conversion article I read talked about the tones being different somehow. I did find that a bit confusing as the standard PL tones are, standard.

[@TheRadioShop]

No difference in commercial and amateur PL tomes. All the same. They just decided to run with no PL on this one. I have worked on quite a few of these models. Since there is many cut wires from the accessory jack is probably why it does not repeat. Probably had a controller running it. Hate to see this one stripped as they make nice repeaters and easy to maintain. Nice tear down.

[@loughkb]

We've got three uhf repeaters in the area and they almost never get used. No need for another. I'll probably list the modules on ebay and use the power supply for a much needed bench supply.

[@thaddeuswrzesinski9803]

the tied in a IDer / controller into the front panel. the Take Over button defeats the DC or Tone Remotes for use in local control.

[@thaddeuswrzesinski9803]

The Duplexer installs under the transceiver unit in that open space by the coax cables

[@pierremartel3552]

the 2 eeprom that need to be reprogram are the 2 small 8 pin chip. the large one is NOT to be reprogrammed. on the front larger pcb there is a single 8 pin chip and it is the one that need to be removed (put a new socket) and programmed to change the frequency.

[@thaddeuswrzesinski9803]

You program the frequency EEPROM via that little black plug on the top left of the control board. Use the KPT50, or KPT-20 programmers, very easy. The same programmer will also set the "EIA standard" CTCSS tones on that little 8-pin "93C46" EEPROM.

[@thaddeuswrzesinski9803]

The frequency control EEPROM 93C46 is soldered onto the front control board.

[@ve6idk]

Did you ever get around and use the amplifier board?

[@loughkb]

Nope. Sold the parts.

[@deandavidson9929]

the small eeprom is a 9846 it holds the PL tone there is a second eeprom same number on the front panel board 9846 notice the black plug on the left top edge of that boardthat is the eeprom programming port that one is for the frequency. The eprom you pointed out is just the firmware for the internal controller. yes you can remove the eeprom from the front panel and install a socket and use an eeprom programmer to read edit and reprogram it to any frequency same as the one for the tone controller. but you must do some math and converting from decimal to hex then entering hex in backwards and writing the eeprom or you can use a kpt-50 programmer which is expensive but I have 1 and I have eeprom replacements if someoe needs a set programmed I would be happy to help. 73's K4ATR

[@dwgelle]

I tuned mine down to Ham bands easily. Have to program the emprom and then tune the radios with analyzer.

[@JDtheEE]

Don't tear it apart! put it on the air! that repeater looks to be good enough to put on the air with a 100$ duplexer. They will tune the duplexer for you in most cases.

[@loughkb]

We've got three uhf repeaters in the area and they almost never get used. No need for another. I knew I'd get comments like this one though! Ha! I'll probably list the modules on ebay and use the power supply for a much needed bench supply.

[@warplanner8852]

Kevin, only three? Here in SoCal we have virtually ALL of the 440 pairs (20 Khz centers) with repeaters on them and 99.99% of the band is quiet as the tomb. I echo the recommendation to set it up. Betcha no one's on the 449.0- pair so a pair of duplexers and a simple antenna at the house and with the topography of Fort Wayne you could cover all Northern Indiana! Go for it!

[@jesusm.perezgonzalez6026]

porque siempre hacen los videos donde no se ve nada sino la espalda ..... e para que explicar cosas sencillas de como se quita los tornillos es una perdida de tiempo

[@ri3cjoh]

Your click areas at the end aren't clickable.

[@z1catfish]

Just put one of those on the air as a GMRS repeater. UHF sucks... lol.