Keith, Looking at the top of the cavity, on the probe/loop where the coax connector is, you'll see the connector body and a small golden cap next to it. The cap may be round or hex, but in many cases, it unscrews with minimal effort.
If you know they haven't be touched by anyone and you don't have the proper test equipment, LEAVE THE INTERNAL CAPACITOR ADJUSTMENT ALONE..!!!! Put the cap back on it and smack your hand anytime you're tempted to touch it. Otherwise, you will be big time sorry. Unless you have a spectrum analyzer with a tracking generator, some good cables and a few quality pad attenuators, adjusting the notch is not for the faint of heart or quick tempered people. Especially with basic test equipment. The small piston type cap adjusts the notch frequency. If you have the described type of probe on your duplexer, set one each cavitiy up using the top rod as the Pass frequency and the leave the cap alone. Use the probe/loop rotation as the insertion loss and if you have no bench mark for an initial setting, set each cavities probe for .6 dB insertion loss as a generic starting point. Then place the two tx cavities back in series and adjust them into a proper load. back later... cheers skipp025 @yahoo.com www.radiowrench.com > "Keith Beckmann" <[EMAIL PROTECTED]> wrote: > Maybe I'm missing something then. All I'm adjusting is the rod and turning > the coupling. > > There is a small hex cap on top of the coupling, that I didn't touch. > > The manufacturers tuning instructions for this model say to adjust an > external tuning stub, which I don't have. > > > > ----- Original Message ----- > From: "skipp025" <[EMAIL PROTECTED]> > To: <[email protected]> > Sent: Thursday, November 06, 2003 3:38 PM > Subject: [Repeater-Builder] Re: 220 Duplexer Tuning Help > > > > > > > I'm trying to tune the high side of a TXRX WP-652A duplexer. > > > This is the duplexer where the couplings adjustment is > > > loosening 3 screw on the duplexer connector and turning > > > the assemble to adjust the reject frequency. I'm > > > using this on the 220 ham band, 224.84 TX, 223.24 RX. > > > > I don't know the specifics of your model, but the top adjustment rod > > should set your pass frequency, the capacitor rod or probe cap > > adjustment should set your notch frequency and the probe rotation > > should set your insertion loss. > > > > Get a handle on how a single cavity operates, the after you get things > > back toward square one... connect the two cavities and readjust for > > the pair (which will be different). Of course it's always best to > > follow the mfgrs instructions. I'll look to see if I have them in my > > files. > > > > cheers > > skipp > > > > skipp025 @yahoo.com Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
