The answer also needs to account for the fact that the duplexer might already be imperfect in its tuning, especially if it's old or has been moved around. 12.5 kHz one way might be fine...12.5 kHz the other direction might be noticeable.
73, Paul, AE4KR ----- Original Message ----- From: skipp025 To: [email protected] Sent: Sunday, June 29, 2008 10:24 PM Subject: [Repeater-Builder] Re: Frequency Change do I retune duplexer? > [EMAIL PROTECTED] wrote: > I'm going to disagree here. Gary said he's only moving > 12.5 kHz, & I've never seen any coaxial resonator in common > use (that means VHFLB cavities being used @ UHF don't count) > that has enough Q that 12.5 kHz is going to make a > significant difference. You've never taken a real close-in detailed look at the notch of a high quality UHF cavity..? A misaligned notch point 12.5 KHz off can be many dB of useful protection is misplaced. > I say don't bother having the duplexer retuned unless you > think it would need retuning without any frequency change. > Bob NO6B It's OK to disagree and its also OK to be detail orientated when you're trying to get the maximum possible performance. I vote the later... cheers, s.
