Pira.cz Technical Forum

Utilities => Silence Detector => Topic started by: chaskins@vistaradio.ca on October 26, 2022, 11:18:56 pm

Title: Using a silence detector to detect that a transmitter is off the air not easy
Post by: chaskins@vistaradio.ca on October 26, 2022, 11:18:56 pm

We have several FM radio sations with a wide variation of fm receiver hardware.

The pira silence detector works well to detect silence but it cannot normally distinguish between regular audio levels and a wide band noise produced when the transmitter is off.

The solution for this is to run 2 detectors
One for silence one for noise detection.

The trick is that the noise detector is always in alarm
when it is satified the email it sends out is that we are off the air

Contact me if you want more information.

Title: Re: Using a silence detector to detect that a transmitter is off the air not easy
Post by: thatjackelliott on December 13, 2022, 01:36:32 am

Very clever. Here I am using an off-air tuner that mutes with no carrier.

Title: Re: Using a silence detector to detect that a transmitter is off the air not easy
Post by: chuck on December 13, 2022, 04:05:02 pm

Using a tunner with a mute is the ideal however i enharented 9 receivers without a mute.
This is a inexpesive solution.

Title: Re: Using a silence detector to detect that a transmitter is off the air not easy
Post by: thatjackelliott on December 13, 2022, 08:43:07 pm

One always prefers the inexpensive solution over the $$ one. We have only the one transmitter to monitor.

Title: Re: Using a silence detector to detect that a transmitter is off the air not easy
Post by: thatjackelliott on December 13, 2022, 09:01:14 pm

Just  to confirm, you find that the wideband no-carrier noise sits lower in amplitude than your normal program material?