I didn't specify it had to be a cavity. Try shorted stub type, just steal a 1000 ft roll of standard issue cable guy RG-6 and go to town.
Or use a L/C filter. It would be an intresting experiment anyway. On Wed, 22 Dec 2004 00:51:36 -0500, Thomas Oliver <[EMAIL PROTECTED]> wrote: > > Do you have any idea how big a 600 khz notch cavity would be? > > About 400 ft > > We had problems here in the Flint area with two paging transmitters that > were 600 khz apart also 152.240 and 152.840 one or both are off the air now. > > tom n8ies > > > [Original Message] > > From: DCFluX <[EMAIL PROTECTED]> > > To: <[email protected]> > > Date: 12/21/2004 11:09:12 PM > > Subject: Re: [Repeater-Builder] Digest Number 2865 > > > > > > What about building a notch circuit tuned to 600 kHz? And then put > > one each on both TX and RX? > > > > > > On Tue, 21 Dec 2004 20:06:10 -0800, Neil McKie <[EMAIL PROTECTED]> > wrote: > > > > > > > > > A new VHF paging system just was installed near here in the > > > last few weeks. > > > > > > Rich wrote: > > > > > > > > 155.820 > > > > BEND, CITY OF WNNU934 > > > > 100 watts Overturf Butte (Bend) > > > > 100 watts Awbrey Butte (Bend) > > > > 300 watts Wampus Butte (La Pine) > > > > 300 watts Gray Butte (Madras) > > > > > > VHF paging is apparently here to stay - whether we like it or not. > > > > > > Neil - WA6KLA > > > > > > > > > Dan Hancock wrote: > > > > > > > > We had exactly the same problem in Ann Arbor. The > > > > pagers were exactly 600 kz apart and up in the 158 Mhz > > > > segment. We installed notch filters and sharp > > > > band-pass filters on the repeater with some success. > > > > Nothing kept it our entirely. I was about to try a > > > > crystal filter on the front end when the interference > > > > just ended. One of the transmitters was taken off the > > > > air. Note though in our situation, the pagers were > > > > there first. > > > > > > > > I can't imagine in this day and age, with the death of > > > > VHF paging being on the near horizon, why anyone would > > > > put up a NEW VHF paging transmitter. However,if one of > > > > these pager transmitters is indeed a new installation, > > > > it may be possible to force them off the air. I can't > > > > quote the section, but the FCC told me one time in a > > > > different interference situation that a new or changed > > > > transmitter operation it totally responsible for > > > > solving interference related to their transmitter > > > > within 5 miles of their transmitter, even if their > > > > transmitter meets specs. This rule might possibly just > > > > apply in this situation. They have installed a new > > > > operation that produces an uncurable mix that wipes > > > > out your operation. That mix could be occurring in > > > > your transmitter, your receiver, one of the paging > > > > transmitters, someone else's transmitter, etc, etc, > > > > etc. I would suggest that you immediately contact your > > > > nearest FCC field office and discuss this with them. I > > > > wish I could give you the section, but the engineer > > > > who told me about it never actually quoted the > > > > section. > > > > > > > > Good luck. > > > > > > > > Dan Hancock N8DJP > > > > President, RADAR Inc. > > > > www.qsl.net/wr8dar > > > > > > > > > > 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/
