Yup, seen it before. The Kenwood TKR-820s we have do just that until you modify it. You can create perfectly clear audio (kind of tinny) just by yelling at the repeater in a VERY loud voice. It's particularly not too much fun if you have it in the same racks as a noisy fan deck. The vibration from the fans will be audible easily during hang time. One time we even could tell the burglar alarm was going off in the repeater building because we could hear it during hang time. Handy, but not the desired effect.
The fix was to open the repeater and find the VCO board. It's a little vertical SIP board that isn't supported except by its solder pins. Flick it with your finger and it's like ringing a bell. Just take a little bit of RTV (non-acid, of course) and put about a pea sized drop between the top corner of the board and the edge of the nearest point of the case. That dampens out the vibration and the problem is gone. You never know! 73 de N1FNE -----Original Message----- From: ve7ltd [mailto:[EMAIL PROTECTED] Sent: Tuesday, December 23, 2003 2:39 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] What causes a repeater to become microphonic? I have a Harris Alpha 2000 UHF (ex radio telephone) running full duplex service, which has been in service for 7 years now... Great radio. We had some recent additions to the spectrum in Vancouver, so I had to remove my preamp. When I did, I noticed that the carrier hangtime of the repeater had a lot of noise on it. I was in the repeater shack talking to myself, when my buddy came on and keyed up and said "Your transmit audio is WAAAAAY to low". To myself (I was thinking) I said out loud "you must be on crack, I havent touched anything". Then, to my suprise, he replied.... Then I realized all I had to do was yell at the casing, and he heard me fine.... This is the only one of these repeaters I have in service that is this way, and I dont think it was before. My old frequency generator is also microphonic, but that is ancient. Is it something to do with synthesizers? What causes a repeater to become microphonic? Dave Cameron VE7LTD 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/ 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/
