> "Eric Lemmon" <[EMAIL PROTECTED]> wrote: > Gene, > I recently converted a UHF Hamtronics REP-200 repeater to 220 MHz > by changing the receiver, exciter, and power amplifier to the 220 > versions. It is working well, and has not had any problems. > > The only reason why I did this was because neither Motorola nor > Kenwood offered a commercial-grade repeater for the 220 Amateur > band.
I ran into the same problems... the major choices available at the time are/were Spectrum, Hamtronics & Maggiore of which I own all of the mentioned. Credit where due the Maggiore stuff has been install and forget it so far... working 100% as received. Depending on who, what, why and where... I would also consider some of the GE and Motorola conversion paths for quality performance at a very good dollar value. Scott and Kevin offer some really nice conversion products for the home brew people. > In my opinion, the major deficiency in Hamtronics repeaters is the > bare-bones power amplifier. These units have no power regulation > and no high-VSWR protection. Keeping in mind the cost of a Hamtronics PA vs something by TPL, TE, or some of the other amplifier mfgrs... you get what you pay for. Oh yeah don't forget Ramsey... > I know of two Hamtronics 2m repeaters that suffered blown PAs due > to antenna problems. With no protection against high VSWR, > the PA transistor smoked. To prevent that from happening in my > "new" 220 repeater, I installed a Telewave single ferrite isolator > to maintain a constant impedance load seen by the PA. It's not hard to build a power control circuit into a Hamtronics PA but would it be worth the trouble when you have a circulator? Most classic power contrul stages simply roll back the/any driver transistor collectory (supply) voltage. Just depends on what, why and how you control the power really. > Rather than buy a Hamtronics 2m repeater, I'd go for a Motorola > R1225 full-duplex transceiver. You get commercial quality and a > complete controller in a package that has more power, and for > less money than the Hamtronics package. > 73, Eric Lemmon WB6FLY What... no mention of Kenwood? A TKR-720 or the even newer TKR-750? cheers, skipp ps: I've added power control to homebrew and Hamtronics kit type power amplifiers... if anyone really wanted to talk about it I'm happy to share the information. s.
