At 11:11 AM 11/24/08, you wrote: >Hi all, > >Can anyone provide some information on the Kenwood TKR-720 repeater? >I checked eham.net but did not find any reviews. What I'd like to know: >- Does it have good sensitivity
Depends on how you tune it. Unless you know the history of any particular unit you need to assume that you need to check the tuning. >and clear audio? The repeater itself has good audio, the more important question is the user's radios. Are they on frequency? Are the users shouting into the microphone? Is the microphone and speaker operating properly? I ask this because years ago I took care of some radios in a cement plant and the speaker-mics would fill up with cement dust. Then the warm breath of the users would create moisture in the microphones. We ended up having to waterproof the new speaker-mics before we gave them to the workers.. >- In general, is it a good repeater? It's Kenwood's oldest low end unit. The TKR-720 and it's UHF brother TKR-820 were discontinued around October/November 2004. Kenwood not longer supports them with parts. Yes, some dealers still have some items on the shelves, but finding the part you need depends on how well the universe likes you that day.... The TKR-720 is a highband repeater that does 15 watts at 100% duty cycle, and 50 watts at 50%. Power is set by an internal manual adjustment. Personally, I think the 50 watts is optimistic. There just isn't that much heat sink. I'd use an external fan on anything over 10% duty cycle.. >- Can it be easily tuned down to amateur frequencies? The following comments are based on the fact that the USA amateur band is from 144-148 MHz, and most repeaters are in 146-148. I do not know what the amateur radio repeater frequencies are in Cyprus where you are. The TKR-750K1 version is for 146-174 MHz, while the TKR-750K2 version is for 136-150 MHz. These are RF hardware design limits, the K1 version does not perform well in the 144-146 MHz portion of the 2m band and cannot be "stretched". You have to buy the version you need. I have seen an early production unit that did not have the K1 or K2 on the label and was a K1 series internally. Once you have the proper range unit then the programming and tuning is very "by the book". And the books are on <www.repeater-builder.com> >- How can it be programmed? Do we need special software? Programming is done by either a KPT-20 programming box or by an the KPT-50 hardware programmer and the matching software. There are people on the mailing list that have the programmer. You can mail them the memory chip and the frequencies you need and they can mail you back the programmed chip. If you trust the timeout timer in your external controller you can have the timeout parameter in the chip programmed as disabled. The K1 version repeater takes the KPG-66D software. The late-model K2 repeater takes KPG-91D software. The software does not interchange between repeater models / versions. The internal controller is very basic, and in most amateur radio applications you will want to use an external controller. My interfacing notes are at <http://www.repeater-builder.com/kenwood/tkr-n20-notes.html> >How would you compare it with the TAIT T800 units (if you are >familiar with both)? Tait is not that common in the USA, but is well regarded by those that have them. >73, > >Andreas - 5B8AP Some additional info is on <http://www.repeater-builder.com/kenwood/kenwood-index.html> about 3/4 to 5/8 down the page. Mike WA6ILQ
