Strange Things that Happen!!!

Hey All,
I don't know if anyone here (other than me) does work
on School Sound PA System. Recently I had to add
six(6) Modular Class Room Speakers to the School System.
Pulled the speaker cables (22/4 Shielded) from the office
system to each of the classrooms. This all happened before
school started 4 weeks ago. I was just informed that the
one room M-105 there was noise of some kind on the Listen.
If you don't know. When the Listen Button is pressed you can hear
what the teacher is saying and then when you press the Talk
Button the teacher can hear what you are saying. Similar to
a basic Intercom System.
Well the sound is a Tikity Tikity Tikity in the background.
To make a long story shorter. I think I figured it out today
that when I made a splice on the wires I left a 4-5" tail and
beanie spliced each wire and then folded the wire inside a
metal 4"x4" box with metal cover. In the same closet there
is a Security Panel, Fire Panel, and some IT Network Data
Switching. The Data Switch has a Cooling Fan and it is making
a noise of sorts.
What I ended up doing was to take some Tin Foil and wrapped up
the spliced wires and stuffed it back into the box. I know it is
early but the Tikity Tikity Tikity has gone away.
At least to MY EARS!!
I am thinking that the fan or something was putting out some RF Noise!!
And the wire tails were picking it up and amplifying it to the office.
Adding the Tin Foil has blocked the noise and hopefully fixed the issue.
I will know more when staff gets in on Monday...................
Hope you enjoyed the read!!!
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So inclusion a tin foil may actually stop the voices.
Reply to
Bob La Londe
Only if the foil is placed properly in the hearing canal!!
Reply to
Hi Les
Well, I found out the if I place the foil in the ear canal just right, between that and my tinfoil hat, I can sometimes get good Country music from WWVA Wheeling West Virginia
Anyway, with regard to the "Tikity Tikity" sound: Are there any alarm systems or keypads around? Did the clicking sound like if might come from a an alarm keypad? Like the sound you get with a wire toner probe? . Also, some of the three separate types of fire alarm system signaling paths can emanate clicking sounds. From initiating device circuits (IDC), signaling line circuits (SLC), and notification appliance circuits (NAC). Depending upon the type of panel being used and if any of your audio connections have exposed pigtails (Even the tiniest strand )they can act as an antenna. . Also are you grounding one end or both ends of the shield? And since you are using metal boxes could any of the shields in the boxes be touching the metal box which may be grounded? Ground loops can drive you Koookie ! !
Reply to
Jim Davis
For a new appreciation of "Foul" language.. . Get a system with "intermittent" ground loops.. or a system in the neighborhood of several high power 2-way radio's (or even low power if there the home built versions..) RTS
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LOL. Years.. well decades ago we were running an 82A carrier over several miles of open wire. 6 channel analog carrier for 6 POTS lines. Its not intended for open wire, but it worked mostly. The thing is it was plagued with intermittent noise. My supervisor finally found the problem. He was climbing the poles one at a time checking the insulators when he found a piece of bare copper wire wrapped around the pole, and reaching out a ways to rub on one of the wires. When it was dry and the wind was dead calm there was no issue, but if the wind was enough to make the wires move it would be noisy on all 6 channels. If it rained it would ground out and kill the system. Usually by the time we could get out after a storm to start checking things it had dried enough that the system was working again. We replaced channel units, cross connect wire, and repeaters before he finally found the problem.
Reply to
Bob La Londe
ROFLOL!! Those kind of problems will drive you nuts!! In a past life as a Maintenance Supervisor in a Plastic Company, there was a DAY!!
The operator on a extrusion line making American Standard Toilet overflow pipes that would be installed in the rear tanks. The cutoff saw was cutting to length of about 9" +/- At some point the saw started to act up and in some way. The operator came back the Maintenance Shop and told me the problem. I grabbed some tools and walked out the saw. It was working just fine............. I stood there for about 2 minutes which meant that it had cut about 40 or so pieces of pipe. I shrugged my shoulders and started back to the shop. I got about 20' away and the operator hollers out to me. "There it goes again!!!" I turned around and went back and it worked just fine................. Another 2 or so minutes went by and another 40 - 60 pieces were cut off. I again started for the shop. When I got about 20' away (I noticed that there was a concrete joint in the floor) I stepped across the line and the operator hollered out again. I walked back and again all was good. I explained to the operator that "I" can't fix what "I" can't see. Soooooo get another saw out of the equipment area and do a swap. Bring this saw back to the shop. I will tag it for inspection. I walked away! That afternoon I had my guy's pull the saw into the shop for a full inspection. Checked all wires, terminals, air cylinders for leaks, all bolts tight, everything secure, a complete look over. They found nothing, zip, de'nada of anything wrong. Placed the saw back into the equipment area and never heard another issue of any kind!!!
I wanted to blame the crack in the floor. ;-)
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I used to follow the HAAS Tip of the Day (lately its just sales hype) on YouTube and they had an episode where they discussed just such issues. I forklift going by on the shop floor would throw all the parts out of spec. (They were chasing a lot tighter tolerance than a saw.) The site wound up cutting out the floor and placing all their machines on isolated poured in place concrete bases.
In another shop the machine was running on blocks on a compacted dirt floor and meeting tolerance every time.
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