BCD325P2/BCD996P2: BCD996P2 intermittent humming sound

Yesterday my BCD996P2 started making an intermittent humming type of sound after receiving a transmittion. It will continue to make the noise until I press the scan button, or turn the scanner off then on.
I monitor the Charlotte County Florida Public Safety System, which is a Motorola Type II Smart Net System. I have a Antenna Craft ST2 antenna mounted on my roof, and receive a strong signal. I've tried using the stock antenna, turning sqelch all the way down, have the latest firmware 1.05.02 installed, deleted system from scanner and downloaded system again from RR. It doesn't seem to be any particular talk group, Happens even if scanner is not connected to pc or any other peripherals.
So now I'm back to using my old BCD246t, and it work fine for what it does, but my 5 month old BCD996P2 is basically useless to me, as that system is the reason that I purchased it.
Any help would be greatly appreciated..Thanks in advance. Vin Napolitano

sent a pm

with some oddball questions.

Does the scanner hang on the TG while it is humming or does the hum continue after the scanner resumes scanning?

Does the system use an end code and do you have end code enabled?

Does this occur on any other systems or channels, or on any specific frequency on that trunked system?

Sometimes interference on a voice channel frequency can cause a scanner to hold on a frequency after the TX ends. The end code may or may not prevent this. Turning the squelch up may help too.

The scanner does hang on the talk group, and continues to hum until I press scan. Happens on any talk group I only have the one system installed on the scanner, with 6 talk groups enabled. Not sure about the end code being enabled or not. Will check when I get home. Thanks for reply.

When it "hangs" check the frequency. If it is the same all the time it is probably a problem on the system itself. We had a problem on one frequency on our county system and it persisted until they made adjustments.

End Code Enable fixed humming noise!

Well thanks to W8RMH the problem is solved. I went back into settings and enabled end code and the humming has stopped. Thank you W8RMH.

I thought it was either going to be that or that the scanner knew the tune but not the words.

With end code not enabled, the scanner relies on carrier drop detection to know when to return to the control channel. If squelch is set too low or if there is some interfering signal on the frequency, when the comms end, the scanner continues to see a signal and so never returns to the control channel (and presenting whatever noise is on the voice channel frequency).

Way back when I was in retail electronics, I said that to a customer who brought in a stereo that would only hum. He was not amused. My boss was, but also told me that I couldn't say things like that to customers.

Just one of the reasons I didn't last in retail.

UPMan said:

I thought it was either going to be that or that the scanner knew the tune but not the words.

Click to expand...

That's pretty funny Gary. At least your boss had a sense of humor.
I noticed that when I heard background garble or static that the problem would start. Squelch position didn't seem to make a difference.