This is what an AP we have at 118’ at White Stone, Virginia sees. If anyone can identify the broadband system present at 909-919 MHz, I would greatly appreciate it.
That system is “hopper like”. I think it is some sort of trunking system. When I check that portion of the system with a hand held scanner I hear telephone conversations. Clearly this is not a cellular telephone system but it does “touch” the wireline services, as I have heard things which clearly indicate that it is attached to wireline service. Having been an electronic warfare tech during my military service, I am fully aware of the legal implications of monitoring telephone. Currently I can use a Yagi and the spectrum analyzer tool to collect line bearings on this signal and therefore have no need to demodulate the signal to obtain locative data.
This signal is so strong (typically around -36 dBm no matter where I go in our service area) that when it is present I can remove the antenna from my scanner and not loose the conversations. I’ve been working on DFing the signal and have about decided that there are multiple sources for the signal in our area. This would suggest multiple towers and some sort of trunking system. The power levels are so high that either this system is operating illegally or it has some sort of “special dispensation” from the FCC.
Any help would be greatly appreciated.
Thoughts.
I can’t say that I know a whole bunch about it, but if I understand what one Gentleman who operates a HAM radio told me, I believe he said that they could operate in the 900 spectrum, but they usually wouldn’t because they prefer far lower frequencies for better distance travelling. But, also, if I understand correctly, they seem to have some sort of special allowance that allows them to put a whole lot of juice behind their signal. My thoughts anyway.
daveamd wrote: I can't say that I know a whole bunch about it, but if I understand what one Gentleman who operates a HAM radio told me, I believe he said that they could operate in the 900 spectrum, but they usually wouldn't because they prefer far lower frequencies for better distance travelling. But, also, if I understand correctly, they seem to have some sort of special allowance that allows them to put a whole lot of juice behind their signal. My thoughts anyway.
Amateur Radio Operators can run up to 1,500-watts from 902-928MHz
and they can run voice, CW, RTTY/data and a few others. The general rule of thumb is that as a ham you're only to use the necessary amount of power to complete the communications. In other words, if you can get by with 1-watt, then you're to run 1-watt. But, if it takes 1,500-watts...so be it.
Most hams don't run on 900 simply for the fact that equipment is not readily available. Most equipment has to be modified from commercial gear to get it working.
There are certain places that have a lot of people using voice repeaters but the signal wouldn't be a hopper.
Dan