Feedback on North/South Camera

[Jason Rose]

Not sure what is causing the feedback/whine/squeal on the north/south camera microphone. We're working on it.

[Larry Sullivan]

Jason - as I said the other day, that seems to be the same noise we were hearing last year. There was no noise at all on the weekend, and I never hear it at night. We felt last year it was something being picked up in the machine shop (there is a thread out there with that discussion I'll find it again for you.). It does drive you nuts at times, but I don't think it's a mic issue at all.

Larry

Here's the discussion from last year that makes me think it's the same sound. viewtopic.php?f=79&t=1885&hilit=camera+noise I think this all started shortly after the new mic was installed, and we didn't hear it all winter either. Hope this helps.

[Jason Rose]

I tend to agree, Larry. Nothing I've been able to do changes the sound. If it was feedback, tweaking the gain should effect it. It doesn't. Sure seems like either an external sound or some kind of external interference.

[Steve Forney]

I have yet to hear the noise. Perhaps it's not loud enough to overcome the 1970's acid rock I've been listening to, at +110dB.

[Rich Murray]

I've been hearing it!! Interferes with this old fella's naps.

[Larry Sullivan]

I've been hearing it!! Interferes with this old fella's naps.

Completely silent this morning until just about 2 minutes ago 7:10 in Chama, and I've had the cams on working here for the last 90 minutes with absolutely no whine sound. Besides you shouldn't be napping at this time in the morning!!!! As an added note it started shortly after they opened the left bay door on the shop - no clue if that would hone us in on any clues. Something is resonating at a frequency that microphone just tunes into, I can also hear it on the depot cam, but have to have volume all the way up and it's a distant sound, as you would expect something coming from the other side of the yard. We know it's not camera related, but sure would be nice to figure out exactly the cause.

[Rich Murray]

Larry I hadn't been able to hear on the depot cam. I have to mess with it and try to duplicate your results.

[Larry Sullivan]

Larry I hadn't been able to hear on the depot cam. I have to mess with it and try to duplicate your results.

See if this helps - about a 20 second recording of the depot cam, tipple cams muted, my speaker and cam volume at 100% It's fairly faint, but I think you can hear what I'm talking about.

[Rich Murray]

Larry, I am able to get the sound now. Which means of course that I wont be able to ignore it!
It must be coming from the shop's air-conditioner.

[Allan Kirkpatrick]

While watching the yard after everything was shut down, I heard the whistle on both the north and south cameras.
Since there was no activity from the shops, is it fair to assume that the whistle is not coming from the mics picking up external sound, that it is some kind of impedance mismatch or other internal problem?
Sometimes when there are long runs (sometime short) of cable, if both ends are grounded, you can get problems.
Removing the grounding on the cable on one end helps especially if power is being supplied from different phases of a three phase system (ground looping).
Hope this helps.

Allan

[Quentin Lockwood]

I believe the noise is from one of the locomotives, possibly the dynamo, or a pressure relief valve.

[Steve Forney]

Currently there is only one mic on the coaling tower. It feeds both cameras through a splitter. Whine in one camera only would suggest the problem may be internal to that camera.

Jason removed one mic (the south one, I think) to use on the new depot cam. However, that mic has a bad cable and was not installed. Until a replacement mic can be purchased (hint, hint) the depot camera is using it's internal mic. The internal mic is not satisfactory because of rain / hail noise, among other things. Jason is off to Oklahoma this week for work, so will be limited in what he can do remotely.

[Jason Rose]

Larry, great work. If you're hearing that same noise on the Depot Cam, it's got to be an external sound or interference.

As Steve said, I'm doing a tour of north Texas and Oklahoma this week for work... and dodging tornadoes. I'll troubleshoot as time permits, but there won't be much free time to spare.

[Jason Rose]

For what it's worth, BrownRice fixed the preview images last night. Some tweaking was needed on their end.

That about wraps up this project. I've got some notes for everyone, but that'll have to wait until I have time to compose a proper post.