Close Call & Trunked Systems

[Ubbe]

A long time ago I got CC hits from users on a trunked EDACS system in the 400MHz band, the hits came from the voice frequencies as the control channel signalling are just a short blip, but they scrapped that system 10 years ago and replaced it with a Tetra system, so I cannot test with a modern BCD536 scanner to see if something have changed in its CC functionality that for some reason would rule out EDACS transmissions. But logically it should detect any signal that are constant for at least 1 second or so if the rest of the frequency band are fairly quite.

/Ubbe

 

[ScubaJungle]

@Ubbe
To update, I've been unable to get any CC hits on EDACS. It seems like the digital threshold was just a coincidence, and I get CCs sitting at home regularly from nearby hospitals. P25, DMR, etc no problem, but doesn't seem to work with EDACS.

I can't think of any reason why it would work for you and not in this situation, maybe a noisier spectrum with more cell phones?
The only other thing I can think of, is could the input frequencies be in a really noisy part of the spectrum?

 

[jonwienke]

The only other thing I can think of, is could the input frequencies be in a really noisy part of the spectrum?

That is the most likely explanation. The design of close call only cares about signal strength, not modulation or digital format.

 

[ScubaJungle]

That is the most likely explanation. The design of close call only cares about signal strength, not modulation or digital format.

Looks like this is the only explanation [that I know of].

I was able to confirm this weekend that close-call does not work with my local EDACS system.
I drove over to see the protests/riots 2 or 3 blocks from my place, and I was within 20 feet of multiple officers using their radios - not only could I hear them speaking over the system, but I was also listening to their transmissions directly on the input frequencies, with full signal, and I got no close calls from them.
At the same time, I got close calls from the helos over my head (AM), as well as mall security (~460mhz), both of which were further than the officers, so close call works - just not with local EDACS, I guess due to input frequency area noise.
Whatever the reason, it doesn't work. But the input method works just as good, if not better