Using a silence detector to detect that a transmitter is off the air not easy

[chaskins@vistaradio.ca]

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.

[thatjackelliott]

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

[chuck]

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

[thatjackelliott]

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

[thatjackelliott]

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