Strange issue while setting up feed

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datainmotion

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I already have one feed that has been up for a year now and wanted to start a second feed. I decided to host the new feed on a second computer since I only have one soundcard on the first.

Here's the kicker - in connecting the audio to the second computer from the second scanner (on a seperate antenna), I can clearly hear any audio out of the second scanner on the feed from the first. How can this be? Two seperate desktops, two seperate mono lines from each scanner to each desktop, two seperate antennas run directly to their respective scanners. The only thing the two desktops have in common is that they share a monitor (via an A/B switch). And this is clear audio, as if both scanners were hooked up to the same soundcard.

I'm a bit stumped...:confused:
 

datainmotion

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To add to this, I also tried new audio cables on each and physically seperated them. I also disconnected one of the VGA cables from the A/B switch but still - no joy.

I'm off to run a power extension from upstairs down into the office to power one of the PCs seperately from another circuit.

Stay tuned...
 

datainmotion

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I don't have mics attached to either, but earlier I did mute the mic volume in each audio control panel for grins.
 

datainmotion

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OK - now even with computer #2 physically disconnected from the power strip, I'm still getting the audio from scanner #2 on computer #1???

So...I left the squelch open on scanner #2 and as always that is showing up on the OddCast VU meter on computer #1 as well as coming out of the speaker on computer #1. BUT, in listening to my feed right now from a third machine (online), I don't hear the open squelch online.

So having said that, the bottom line is that scanner #2 audio is in fact NOT getting on the feed for #1 (my only real concern). But it still begs the question, how is it getting on computer #1 to show on the VU meter and out of the speaker on #1??? :confused:
 

datainmotion

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Both feeds are up and running with no crosstalk. I do still get the crosstalk locally though :confused:
 

datainmotion

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Now I can hear the crosstalk on the feed as well :mad:
so I downed the second feed temporarily.

I've got two shielded cables on order to try and eliminate the crosstalk and will head to RS for the Ground Loop Isolator tomorrow..
 

hvscan

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Data, I'm following along from the side lines to see how this works out for you. I have a similar situation, but have not had a chance to work on the problem. I'm hoping to tackle it this weekend. Good luck with yours.
 

Bote

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I'll probably post my results later next week after the cables arrive.
In the meantime you could always try some good old fashioned troubleshooting.

Start disconnecting one thing or changing one setting at a time to see if that affects the crosstalk problem.

Try everything even if it makes no sense at first, since this sounds like a pretty weird problem. Try toggling the audio select settings on feed #1 mixer for example. Look for connections that are common between the two machines, even if they are not audio-related.

Heck, try operating scanner #2 in the other room and see if it can jump that distance.

It will be interesting to see what this really was.
 

datainmotion

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Cables came in and problem still exists with them installed.

Tried the only other thing I hadn't yet and guess what - it's the scanner. I was using an SC-150 so I tried using my PSR-500 and no crosstalk at all. Put the SC-150 back in and crosstalk returns.

So, the feed will have to wait until I get another scanner.

Thanks to everyone for their suggestions and input
 

Bote

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Cables came in and problem still exists with them installed.

Tried the only other thing I hadn't yet and guess what - it's the scanner. I was using an SC-150 so I tried using my PSR-500 and no crosstalk at all. Put the SC-150 back in and crosstalk returns.

So, the feed will have to wait until I get another scanner.

Thanks to everyone for their suggestions and input
So buying a new scanner is cheaper than spending 30 minutes plugging and unplugging things in a systematic way to isolate the exact cause of the problem?
 

datainmotion

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So buying a new scanner is cheaper than spending 30 minutes plugging and unplugging things in a systematic way to isolate the exact cause of the problem?
While I appreciate your advice, you may want to brush up a bit on your people skills.

And since you gave me advice, I'll return the favor. Bolding "in a systematic way" implies that you feel the person you are addressing is not listening to or acting on something you said to them already. I saw your two posts. I wasn't ignoring you but by the time you posted your first, I had already tried everything except the shielded cables and scanner. You came in late to the conversation and while I appreciate your input, I can assure you that not only did I troubleshoot this in a systematic fashion, I decided to ask numerous other folks what advice they may have on this (mostly offline).

The bottom line is the SC150 was the problem. No further troubleshooting necessary.

Thanks for your time.
 
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hvscan

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Wirelessly posted (BlackBerry9530/5.0.0.328 Profile/MIDP-2.1 Configuration/CLDC-1.1 VendorID/105)

Data, thanks for the update on this. I have not had a chance to trouble shoot mine, so I will start with the scanner.
 

datainmotion

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I would have to think that the problem I found with the scanner is rare. While the SC150 is really an entry-level handheld, this is an odd issue for any scanner I would think.

I only saw you post that you "have a similar situation". Not knowing exactly what that situation is, I can only say that the advice posted regarding troubleshooting in a logical, systematic fashion is your first best bet.

I would agree with Bote as well that you "need to try everything, even if it makes no sense".

Good Luck!
 

talkpair

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I would disconnect all the cables, except for the antennas, from both scanners, to rule out this being an RF problem.

I had a couple scanners years ago that couldn't co-exist in close proximity, and would pretty much mirror each other's reception.

If you find this to be your problem, you might try dedicating one radio to one band, and the other radio to another band.

Physical separation may also work.........If the radios are currently stacked on top of one another, move one to the other side of the room
 

Bote

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I would disconnect all the cables, except for the antennas, from both scanners, to rule out this being an RF problem.

I had a couple scanners years ago that couldn't co-exist in close proximity, and would pretty much mirror each other's reception.

If you find this to be your problem, you might try dedicating one radio to one band, and the other radio to another band.

Physical separation may also work.........If the radios are currently stacked on top of one another, move one to the other side of the room
First, sorry for the earlier misunderstanding.

Second, when two receivers seem linked together like that, they are hearing each other's common intermediate frequency. Modern receivers convert the received frequency down to something much lower that they can process, for Uniden scanners this used to be 10.85 MHz but I don't know what they use these days. The most common i.f. used for decades in most consumer equipment was 10.7 MHz

So if scanner B is set down on top of scanner A and they both use the same 10.85 MHz i.f. then there is a chance that enough of that energy could radiate out of scanner A into scanner B so that they both hear the same thing. This is happening in the radio domain, not the audio domain. That is why I suggested running the second scanner "in the other room" or far enough away from the first scanner that this should not occur. With a plastic housing there is less shielding, thus the problem is more likely to occur.

If it's audio, then look for common factors, like power supplies, common grounds, crosstalk among cables running parallel to each other, and so on.

Hope this helps. I'm still curious what the root problem is because this is so weird, and I'm sure others would benefit from finding the cause.
 

datainmotion

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Bote and talkpair,

I appreciate your interest in this problem. The two scanners in question do sit in a stand, in close proximity to each other.

When I swapped out the SC-150 (scanner #2) with the PSR-500, the PSR-500 sat in the exact same position in relation to scanner #1 (BC245) as the SC-150 did. So, it may just be that the SC-150 has inferior shielding to what the PSR-500 has. That wouldn't be a surprise as the SC-150 is nothing more than a base model handheld scanner.

Among other things while originally t-shooting this, I ran an extension cable down into the office from another AC circuit in the house. I used this to power scanner #2 and then later to power another desktop (just to try and isolate). I also tried different, seperate paths for the audio cables and also shielded audio cables.

The IF seems to be the most logical explanation thus far...
 
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