At 1/21/2007 11:14, you wrote: > > There are 7 stubs, 4 are on the pass cans, 3 in-between the 4 > > resonators. Adjusting any of the 3 stubs (between each of the 4 > > resonators) has little effect on the skirt. > >The between adjust the size of the aperature (coupling) between filters. >You won't find a whole lot of change in the passband response as you adjust >them; that's just the way they are (or at least on the few dozen or so of >those that I've tuned). > > --- Jeff
I have 3 of the 5 section Celwave UHF preselectors (5 passband tuning adj. + 4 aperture). I found that the aperture tuning had a small but definite effect on the passband, but as Jeff notes it's not dramatic at all. Perhaps they're really more for minimizing passband ripple. Bob NO6B
