At 2/7/2009 10:27, you wrote: >The auction listing mentions that original MVP Repeater has >only a few watts output. I seem to remember the original MVP >repeater PA being rated about 2.5 to 3.5 watts output? > >Bob and Chuck, > >Are you guys turning down the output power on your conversion >MVP (radio to) Repeaters? ... or running near/at the nominal >radio RF output level without major internal cabinet de-sense >problems?
Nope. Full power on the 30 watt VHF/25 watt UHFs. I do turn down the 40 watt UHF radios down to just under 40, as that seems to be the point of maximum efficiency for those PAs. For the VHF HB radios, an old CPU fan/heatsink combo clamped to the flat back surface & keyed by the (buffered to eliminate fan noise) PTT line provides more than sufficient cooling. The UHF PAs aren't quite as efficient; for those I still use 110 VAC fans that spin 24/7, or in one case where the site manager didn't allow that, larger PTT-keyed 12 VDC fans. No desense problems with the MVP. There is a TX-LO IMD problem in the UHF radios that is documented, along with the fixes, in my MVP conversion article on the repeater-builder website. Bob NO6B
