Hi Randy, I did place a notch cavity in the antenna feed line, tuned to the image frequency of the receiver IF.
As an example Notch 245.750MHz (TV Channel 14 Audio Carrier Frequency) 245.750MHz minus 21.4 IF = 224.05 Receiver IF Frequencies vary a bit... and both Channel 13 and 14 analog are quite happy to provide a strong image source. Original Icom 3AT portables are/were really problematic to use in my area because of poor TV signal image rejection. cheers, skipp > "wb8art" <wb8...@...> wrote: > Skipp, why would you not filter it on the input? > Randy > > > --- In Repeater-Builder@yahoogroups.com, "skipp025" <skipp025@> > wrote: > > > > I remember that Neutec Unit... saw it on Ebay. > > > > Mike > > > > Do you have any analog television stations on channel(s) 11 > > through 14 in the area still on the air? > > > > If so, I might suspect an IF image might be possible. I had > > the same type of problem here from channel 13 getting into a > > number of Icom receivers. > > > > I had to notch the image frequency of my IF to get rid of > > it. > > > > s. > > > > > "Michael Ryan" <mryan001@> wrote: > > > > > > My recent efforts at putting a 220 repeater on the air here in > western > > > Florida have been mildly succesful. I am using a Neutec designed > > repeater. > > > ( I know there are some uhf and vhf models around, this one is on > 220, a > > > RANGER brand ). The repeater is open access. And runs quiet all > day or > > > night, nothing cracking the squelch at all. But during times when > > there is > > > a conversation going on after a few minutes a rather nasty signal > > captures > > > the repeater sometimes in short bursts, sometimes much longer. > > "Sounds like > > > someone talking into a reverb chamber.." I had been using a > Mirage > > brick > > > amp in the rack, but suspected that this amp might be the > problem, some > > > oscillation or internal mixing of some sort. This turned out not > to > > be the > > > case, the amp though still in the circuit is OFF but we still get > the > > > garbage. When the amp would be ON, and I would sometimes hear > this > > stuff > > > start, and I could turn OFF the amp an it would stop. But > shortly later > > > even with the amp OFF, it is back.very odd that it would appear > to me. > > > > > > Now, all cables in the rack are RG-400. Every one in the rack. > Half > > inch > > > hardline runs to the antenna, though there is a splice with a > double > > male N > > > connector as I recall. The Neutec unit does about 25 watts output > > but I have > > > it cut back to about 10 watts thinking it will run cooler. Thus > > with the > > > small brick amp it was doing about 65 watts output to the > Telewave 4 > > cavity > > > duplexer. > > > > > > While at the site tonight, I could hear something getting into the > > recvr. > > > The repeater was UP, but no one talking at that moment. Again, > > nothing on > > > it's own ever appears to break the squelch. The noise was heard > > through the > > > repeater's on board speaker, meaning it was coming through the > antenna / > > > recvr and not something produced in the rack I would assume. > > > > > > There is a cel tower about 1,000ft away and another tower with ( > who > > knows ) > > > how many other users, another 500ft further away. Based on this > > little bit > > > of info what would the masses suggest in first FINDING the > offending > > source > > > if is indeed intermod? Then, is there much than can be done > short of > > > moving my machine? Any ideas or suggestions? > > > > > > n Mike > > > > > >
