Re: [Repeater-Builder] Re: GE MVP output power level
n...@no6b.com wrote: > 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, Huh-wow. I guess they don't have too many commercial tenants then, huh? I know that no paging company could have that restiction! ;c}
RE: [Repeater-Builder] Re: GE MVP output power level
Let's not forget that the MVP repeater in question is the LPI (Low Power Industrial) version, and it comes with a 19C327014G7 PA module that has a range of 1.5 to 5 watts. The MVP LPI repeater was normally delivered with the power set for two watts at the duplexer's antenna jack. More info is here: 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of n...@no6b.com Sent: Saturday, February 07, 2009 8:22 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Re: GE MVP output power level 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
Re: [Repeater-Builder] Re: GE MVP output power level
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
Re: [Repeater-Builder] Re: GE MVP output power level
I have built many MVP repeaters using the NHRC MVP controller. I always test the repeater with full output power. I have never witnessed any in cabinet desense with any MVP conversion I have done, no matter VHF at .6 MHz or UHF at 5 MHz separation. Now, I wouldn't recommend running them that way in repeater duty, but we are talking about in-cabinet desensitization, not how long the PA will last. Kevin Chuck Kelsey wrote: > I'm not running any MVP's in duplex - they are in service as either link > radios or monitor receivers. However, I've used Exec II's without backing > them down much (reduced due to heat considerations). > > Chuck > > > > > >> 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?
Re: [Repeater-Builder] Re: GE MVP output power level
I'm not running any MVP's in duplex - they are in service as either link radios or monitor receivers. However, I've used Exec II's without backing them down much (reduced due to heat considerations). Chuck - Original Message - From: "skipp025" To: Sent: Saturday, February 07, 2009 1:27 PM Subject: [Repeater-Builder] Re: GE MVP output power level > 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? > > s. > >>
