Eric, I agree.. "on the money" usually equates to the maximum performace for your intended application. Unfortunately the result is not always within the designed parameters of the cavity and performance from design specs suffers slightly. But if it suits your needs and performance is acceptable, why not?
73 Mike K5JMP www.k5jmp.us -----Original Message----- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] Behalf Of Eric Lemmon Sent: Sunday, April 09, 2006 9:32 PM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] Sinclair Q-201G duplexer Ken, I think the "stock answer" is the one to follow. Actually, since the bandpass tuning on a typical BpBr duplexer is rather broad, while the notch tuning is very sharp, better results might be achieved by tuning the center (bandpass) rod so that the notch is where you want it, rather than looking for minimum attenuation of the pass frequency. Moreover, the pass-to-notch spacing does not always remain constant as the cavity rod is tuned. I'm so used to using a network analyzer to tune a duplexer, that it wouldn't occur to me to tune only half of the functions. There's real satisfaction in getting a duplexer exactly on the money. I guess I don't understand why the question was asked. With the right equipment, a complete duplexer tuning only takes a few minutes, so there's no great amount of time to be saved by skipping part of the procedure. I've tuned quite a few Sinclair Q-201 and Q-202 duplexers, and I find it useful to tune each cavity separately before hooking them together. Very seldom is any tweaking needed. As always, YMMV! 73, Eric Lemmon WB6FLY -----Original Message----- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Ken Arck Sent: Sunday, April 09, 2006 4:30 PM To: Repeater-Builder@yahoogroups.com Subject: [Norton AntiSpam] [Repeater-Builder] Sinclair Q-201G duplexer Hi folks I know the "stock" answer, but I'm looking for the non-stock one :-) (and yes, I've read the manual!). But I was wondering (and checking my rationale here)..... in many Bp/Br cavities, the notch tuning actually tunes to a certain freq above or below the pass-tuned frequency. Therefore, if moving the duplexer a meg or two but you maintain the same offset spacing, can you simply get away with retuning the pass freq and, all other things being equal (port impedance, etc), is that all that is needed? Manuals always seem to talk about tuning but rarely (if ever) REtuning... Ken ---------------------------------------------------------------------------- -- President and CTO - Arcom Communications Makers of the world famous RC210 Repeater Controller and accessories. http://www.ah6le.net/arcom/index.html Authorized Dealers for Kenwood and Telewave and we offer complete repeater packages! AH6LE/R - IRLP Node 3000 http://www.irlp.net 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/
