Hmmmm, let me go back and double check that, might could be a problem there, as one said, what about the cable before the duplexer's. All I know is most of this started after the power supply took a dump, might be it killed something, or my astron 70 amp is not up to par. Will retake the measurements and give them again.
Mathew -----Original Message----- From: Wade Lake [mailto:[EMAIL PROTECTED] Sent: Wednesday, January 26, 2005 7:25 AM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Repeater Rx is Better than TX, Why Dave is absolutely correct. The original post states 160 Watts in to the duplexer and 130 Watts out. That equates to less than a dB of loss through the duplexer ( .9 db to be more accurate ). Wade - KR7K > > Where did you acquire that from this thread? My VSWR was after the > duplexer? > > Mathew > > > > What kind of duplexer has less than a db of loss? (I want one). > > > > > > Dave Baughn > Director of Engineering > The University of Alabama > Center for Public Television and Radio > Box 870150 > Tuscaloosa, Alabama 35487 > 205.348.8622 cell 205-310-8798 > NEW EMAIL [EMAIL PROTECTED] > > >>> [EMAIL PROTECTED] 01/25/05 07:31PM >>> > > At 1/24/2005 07:30 PM, you wrote: > > > > >On Jan 24, 2005, at 18:28, w9mwq wrote: > > > > > > > > > > > Ok, I know this sounds silly, but my repeater is now hearing better > > > than it transmits. Here's the setup, the the issue. I have a > > > Maggorie (no comments) HiPro transmiitter running 2 watts into a > > > Vocom Amp running 160 Watts into the duplexer, 130 out to the > > > antenna, fed with 7/8" hardline into a Diamond Dual Band Antenna at > > > 92'. VSWR is 1.1:1, with 130 watts forward and 1/10 watt reflected > > > at an impedance of 52 ohms, (MJF 259). > > > >I would vote for a failure of the Diamond antenna. I would bet one or > >more sets of the set screws holding the elements together have come > >loose. When this happens, the antenna will still present a perfect 50 > >ohm load, but perform poorly. Diamonds are okay antennas when they are > >new, but they have to be taken down every year or two, disassembled, > >cleaned and tightened up. Really only a decent antenna if you can get > >to it conveniently for the annual repair. You will never see this type > >of failure with the wattmeter or impedance bridge. > > Since this is a 2 meter system, it would make some sense that a partial > antenna failure would result in the TX being degraded more than the > RX. This is because of the relatively high noise floor on 2 meters. Any > loss in the antenna system will directly impact the TX signal of course, > but the same loss will cause both received signal & noise to be reduced by > the same amount. If the repeater RX has a very low noise figure, it's > likely that the first couple of dB of loss in the antenna system will > nearly equally drop both signal & noise as seen by the RX, resulting in no > perceived drop in RX performance. However, any mechanical failure of the > antenna would likely also cause a high VSWR and/or desense, neither of > which are present here. > > Bob NO6B > > > > > > > > Yahoo! Groups Links > > > > > > > > > > > > > > Yahoo! Groups Links > > > > > > > > > > > > > Yahoo! Groups Links > > > > > > > > Yahoo! Groups Links Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
