I hear images from time to time, some more prominent than others depending on the band and the proximity of the transmitters to my location.
Even on the strongest of signals on VHF, I have never seen any images 10.7 Mhz up or down of any strong frequency. Not to say that it doesn't happen, but I've never experienced it. And these signals aren't as strong as some of the signals that shoudl produce images if an image were going to be produced.
It's a triple conversion scanner - The 1st IF is 380 Mhz. It's a bit less likely that you'd see a 21.4 / 10.7 image on VHF as compared to a dual conversion scanner with the 1st IF of 21.4.
I can guarantee that 150.5625 is legit. This definitely is not an image.
150.6000, being so close to 150.5625 could be a frequency to question - although I still receive it clearly with perfect P25 decode with the attenuator turned on... leading me to believe it is not. It's definitely not an image of 161.300 (which is +10.7 Mhz ).
157.6425 was first noticed a few months before I noticed all teh linking going on - and it was the P25 signal present across VHF while I listened to it at that time. They were in PGH area staking out a bar one time with cars getting into positions at the corners of the end of the block the bar was on. I listened to them for a while and at that time intentionally tried to find any other activity on the band while they were talkign. I'm sure there was an input somewhere to be heard, but I was too far away for that. At any rate, since 157.6425 was used standalone back then and then only reared its head in combination with a bunch of others as the G20 approached, I have no reason to believe it isn't a legitimate transmitter of its own vs an image.
I'm not claiming that every frequency I listed is absolutely positively 100% correctly identified as an actual transmitter. But I believe that everything I listed is an actual transmitter with the exception of 150.6000 (which I'll have to check into further).
Look elsewhere? How in the world do you think I came about that list if I weren't looking elsewhere? Hearing 157.6425 initially many months back is what caused me to start searching elsewhere (and at that time for a some weeks it was the only traffic I was hearing P25). When I would hear traffic on it I would scan VHF to find others. Then one day I scanned VHF while hearing traffic on 157.6425 and that's when I started noticing a ton of other transmitters - and I attributed that to them setting up for the G20. I don't always hear all traffic on all of them, but most of the time I do.
Over the weekend i heard a lot of traffic. Today I've been listening all day and have only heard a few transmissions (and all were encrypted).
Given that these frequencies are frequently encrypted, they probably won't make for good listening even in the middle of the G20. There are probably a ton fo other frequencies in use that will prove to be far more interesting (including all the stuff the PGH Police will be using and 400 Mhz frequencies, simplex frequencies, etc).
I'm just passing along what I hear . After the G20, I might never hear anything on the majority of the frequencies.
Mike
