w6nct wrote: > > > > > Actually a network analyzer works better than a combination sweep > > and marker generator. Remember that when you change isolation, > > you are also changing impedance so you need to measure swr as well. > > > > There are other ways. Read Gary's excellent post carefully. > > > > -- > > Larry W1HJF > > rapp at lmr dot com > > > > Unfortunately, I doubt that I can afford a network analyzer either; > and I curently don't know how to use one if I happened to come across > one to use.
I'm sure you don't own one, but you might be able to rent one or borrow one, or better yet, borrow one with someone who knows how to use it! (That's not me, btw!) > I don't understand what you mean when you say "when you change > isolation, you are also changing impedance so you need to measure swr > as well". I expected that the complex impedance of the cavity might > be changing as we are changing its tuning stubs; but I thought that a > resonance (with a low SWR) was essentially what we are getting when we > were adjusting the stubs in the cavity to peak the bandpass at the > desired frequency. Am I wrong in this assumption? I don't know which duplexer you are using, but Sinclair, for example has tuned loops in the can. You can turn them to vary isolation, but when you do, you are changing impedance. I.e., you may be able to do more than just adjust the stubs. > Either way, how do I set this up, and where would it fit in a test > procedure? I can't tell you that unless I knew specifically to which duplexer you were referring, which model (and configuration), and then I would need to be familiar with it. I know some Phelps-Dodge and some Sinclair. I have never adjusted Wacom, TX-RX, DB Products, etc. > Which post (from Gary) are you referring to; and what specifically > should I be paying special attention to? His post dated 4/1/07 at 9:21 pm. He starts out "Duplexer and cavities have been tuned for many years..." Excellent post - one of the best I've ever read. > > Thx, > > Vern (W6NCT) -- 73, Larry, W1HJF [EMAIL PROTECTED]
