Message posted by lone wolf on April 26, 2004 at 7:16:27 PST:

In theory, you can detect a scanner. All scanners have a local oscillator (more if multiconversion) used with the mixer in the process to get the signal to baseband for demodulation. Handheld scanners have plastic cases that are poorly shielded, making it very easy for the local oscillator to escape. [The plastic case may coated internally with some sort of RF paint, but generally it doesn't work well. This is more common in cell phones.] Detecting the local oscillator is not a problem over a short distance, but 26 miles away? There are RF engineers who know how to do the "minimum detectable signal" calculation that could prove if this were possible in theory.

Detecting "real" radio transmissions like a cell phone should be a piece of cake. Whenever I do a cell call from Tikaboo, I ask the other party "Is there anything you would like to tell the operation near Groom Lake?" I'm sure all cell phone transmissions around the ET highway are monitored. Note that even a cell phone not in use does periodic "handshakes" with the cell site, so it can be detected.

Note that the top of Tikaboo Peak is in a very strong RF field, probably from Badger Mountain. The RF from Badger is not a repeater, i.e. you don't see the RF level fluctuate as the repeater is keyed. Rather, it is a constant RF, probably from a data link. Now it may be possible to detect the presence of visitors with this RF.

Regarding radio snooping, I was told a story by someone who was "mountain topping" [a ham term for talking over a long distance by putting all parties on hilltops] on the 220 band near the TTR. A really strong signal did a "break" [announce that you want to stop the conversation of others and break in]. It turned out to be someone in a S3B Viking who said he saw their conversation "on his screen" and since he was a ham, he decided to join them.

In Reply to: Re: range weather posted by cavemonster on April 26, 2004 at 2:07:29 PST:

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