Splatter, noise or ? 450.675 MHz

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Airwind
Posts: 19
Joined: Wed May 23, 2018 8:27 pm

Re: Splatter, noise or ? 450.675 MHz

Post by Airwind » Sun Sep 09, 2018 9:45 pm

That looks like some variant of 4FSK. Did you pick up this signal near a restaurant perhaps? I think some pagers use this exact frequency.

rtlsdrdev-user
Posts: 11
Joined: Wed Sep 06, 2017 4:27 pm

Re: Splatter, noise or ? 450.675 MHz

Post by rtlsdrdev-user » Mon Sep 10, 2018 6:55 pm

Nearby burger restaurant uses 450.002 MHz (pager). Signal could be e.g. sensor which transmits approx. 4 times per hour?

Airwind
Posts: 19
Joined: Wed May 23, 2018 8:27 pm

Re: Splatter, noise or ? 450.675 MHz

Post by Airwind » Mon Sep 10, 2018 8:33 pm

Probably not.

The restaurant pagers seem to ping randomly and are not associated with any periodic pattern. This makes sense because customers will have their food prepared at different time intervals (delays). Finally you can probably correlate the frequency of pings with the number of customers in that restaurant. For example the pings should be very frequent during a rush hour, but non-existent during night-time or the time the restaurant is closed.

If the signal appears periodically then it's not the pager. It's probably some sensor transmitting data at regular intervals.

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