What are these doing here?...

[DSH84]

I monitor a statewide p25 system in CO, with a RS pro 106. I reach 2 towers in my area clearly and two more in a neighboring county. My control channels total of 16, primary's and alternates. Question is I can manually search in "tune" mode and I have seeked out 2 motorolla channels and something else... (i forgot the name now) etc. And was able to look up the users here on RR. I was also able to identify the control channel "noise" thanks to this site also. (they belonged to private communication companies/ businesses or something like that) But also what i've found and am more interested in, is two more p25 control channels that are NOT listed anywhere, nor FCC licensed. the thing is the TSYST I.D. is the SAME and the tower number (or sight #'s) are also the SAME as the ones im used to using. So what Im saying is my ususall CC's range from 852.000-853.000. (exact freq. not important right now). The new channels I have found are clear, and I mean clear as a bell but are at 791.9100 and 792.46125, and there seperate sights and Id's. But i'm confused because i already have listed and licensed tower i.d.'s to the same towers. They seem to work also when placed in there own talksystem although they are the same things (tlkgrps) im used to hearing????.... What the heck are these??? There is maybe a chance I pick up different traffic on them but not neccasarily more traffic if that makes sense...Its hard to tell. All I know is its strange. Any ideas??

 

[Jay911]

That's a known issue with the GRE-built scanners. They receive "images" of 800MHz frequencies in the 790MHz range. Newer GRE radios have actually had the range masked out so you can't tune it in, rather than fix the issue.

 

[markab]

Sorry for the slightly off topic reply but I'm wonder if Jay or anyone else would know if using something like the Band Scope feature in the HP Extreme could be used to determine if a signal on a given frequency is legitimately there or if it's an image?

Mark

 

[GTR8000]

Sorry for the slightly off topic reply but I'm wonder if Jay or anyone else would know if using something like the Band Scope feature in the HP Extreme could be used to determine if a signal on a given frequency is legitimately there or if it's an image?

Mark

As Jay said, this is a known issue specific to GRE scanners receiving images from the 800 band in the upper 700 band. Tuning in those same frequencies with a Uniden scanner would reveal nothing except white noise. That alone would confirm the fact that it's an image.

 

[markab]

image frequencies

As Jay said, this is a known issue specific to GRE scanners receiving images from the 800 band in the upper 700 band. Tuning in those same frequencies with a Uniden scanner would reveal nothing except white noise. That alone would confirm the fact that it's an image.

Hi Chauffeur6,
Thanks for the reply. My understanding is that most scanners will receive image transmissions if they tune their scanner to a particular offset in relation to an actual transsmision. Sorry if I wasn't clear but my inquiry was in regard to this situation. Thanks

Mark

 

[Jay911]

Nope, this is a problem unique to GRE for some reason. I didn't have my HomePatrol when I tried this in an area where a GRE user was having the problem, but I can replicate it in my local area with my own GRE radio vs my HP1 (or 396XT or etc).