Kent, I have seen this sort of problem before in a simaler application. I believe that your duplexer may have a bad internal connection, possibly at a fingerstock contact. In my case the problem was solved by replacing the duplexer. I believe the problem was caused by tuning the duplexer under power rather than with a network analyser. This occured many years ago, so my memory may be faulty.
Best Regards de Eric (W1EL) Eric Lowell Eastern Maine Electronics Inc. 48 Loon Road Wesley ME 04686 [email protected] www.satnetmaine.com 207-210-7469 ________________________________ From: Kent Chong <[email protected]> To: [email protected] Sent: Tue, March 9, 2010 10:31:30 AM Subject: Re: [Repeater-Builder] Noise Level on a Duplexer Dear Joe, Yes, we have observed the signal with a spectrum analyser. It is a broadband noise covering our entire TETRA band. Yes, the transmitter is keyed up continually. Regarding oscillation, what circuitry will develop the oscillation in 3 days? We are thinking about the heat problem too, as heat may be developed overtime. Best Regards, Kent --- On Tue, 9/3/10, Joe <k1ike_m...@snet. net> wrote: >From: Joe <k1ike_m...@snet. net> >Subject: Re: [Repeater-Builder] Noise Level on a Duplexer >To: Repeater-Builder@ yahoogroups. com >Date: Tuesday, 9 March, 2010, 8:52 PM > > > >Hello Kent, > >Have you looked at the noise on a spectrum analyzer? Is is broadbanded >noise, or is it just on your receiver frequencies? If it is only on >specific frequencies, is it frequency stable or does it drift around? > >Also, do any of your transmitters stay constantly keyed up? > >I'm wondering if something external to your system is oscillating. Your >signals may be causing it to go into self-oscillation. When you shut >your system off it stops. This is just a guess right now. > >73, Joe, K1ike > >> >> >> <http://sg.rd. yahoo.com/ sg/mail/domainch oice/mail/ signature/ >> *http://mail. promotions. yahoo.com/ newdomains/ sg/> > ________________________________ Get your new Email address! Grab the Email name you've always wanted before someone else does!
