--- In [email protected], "skipp025" <skipp...@...> wrote: > > Re: Building a notch duplexer with notch cans. > > You would not be restricted to using DB/Andrew/DB-Spectra loops > if the proper type and size were available from another source. > Regardless, the price is probably going to be over $200 minimum > for a 4 cavity probe kit and matching coax harness. I would actually > expect more...
I am curious if andrew still support the DB line of filter (next thing on my list of things to inquire about) > > > we have 4 pass cans at the site in a cabinet that are just > > waiting to have some vari caps installed to make them into > > pass/reject cans. > > The free lunch you think you're going to get by simply installing > the small piston caps in series with the cavity loops is in > my opinion fairly optimistic. I dont think it would be a free lunch, even 10 to 15 db notch on a pass can it still workable, but i am open for your thoughts on the subject. > > > as far as making these into pass/reject, i am not sure how > > you modify the loops. Unless you can add a vari cap on the > > ground side of the loop. > > That's the trick a lot of people are saying will work. It's not > the type of loop/probe I use or make (mine are constructed more > like the Telewave TPRD type) but they may work. The Repeater Builder > Web Site has information about how Hams have modified cavity > probes from Band-Pass to Band-Pass, Band-Reject with reportedly > decent performance and cost savings. > > If you're going to be constructing BpBr Probes, I would suggest > you make new cavity port probes rather than modifying the > originals. > > The materials and parts shouldn't be that exotic or hard to find > unless you live well away from a decent size city... or lose > access to the web/internet and the Post Office. > > s. > Ok i will look through the website and see what i can find. I have an old FM/repeater manual from several years ago, and the arrl antenna book, both provide construction articles and i will look at the loops that they recomend building also. I believe the 2 ways i have seen the loops modified are: 1) vari cap between the loops of a pass can. 2) veri cap inserted in the ground end of the loops of a pass can. are there any others? By the way, i apriciate all the suggestions. thank you to all that have responded. de kd4wov Tom
