Dave: I have a couple of these. They are DB4002. However, the one you have sounds like it is for the aircraft band, but it doesn't look any different than mine.
According to the Allen Telecom Catalog 24 they are located on page 123. They are listed in two band passes for VHF: DB4002-A 118-148 Mhz DB4002-B 148-174 Mhz It is generally a pass cavity. There should be connectors on either ends. I can remove the loops from mine by unscrewing the SO-239 connectors to the cavity. The size of the loops determines the loss and selectivity. They have loops for .5, 1.0, and 3.0 db. The selectivity at 10 db down for .5 db is 600 Khz (300 Khz either side of center). 1.0 db loss, 375 Khz, and 3.0 db, 150 khz. I used to have drawing that DB faxed to me for the loops. May still have them. You can also use them on 400 Mhz. These are DB4002-C 406 - 420 Mhz DB4002-D 450 - 512 Mhz I used one of the ones I have as a bandpass filter in front of a UHF Gaasfet preamp (Out of the duplexer, into the cavity, then into the preamp, then into the receiver). It worked very well. The chart shows that at 1.0 db, 1 meg away, it is 25 db down. 2 megs away it is 32 db down. I would say put them on a signal generator and into a receiver and see if they will tune. I hope this is helpful. Micheal Salem N5MS Dave wrote: > > I have a few of these "barrels" but I cannot find any model or part > number on them. The only info I have is a tag ties to the top that > says 106 - 136Mhz. > > I'm wondering if these are notch or pass/reject or whatever cavities. > > Here is a 44kb picture of what I have. > > http://www.kmcnet.net/Pictures/can.jpg > > Since I have a few of these, I'm thinking I might be able to make a > duplexer with them .... any thoughts? > > Thanks > > Dave / N9NLU > > > > > > > > > > > Yahoo! Groups Links > > > > > > > > Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
