Re: Strange Things that Happen!!!

[Bob La Londe <none@none.com99>]

On 9/27/2022 8:13 AM, RTS wrote:
> On 9/26/2022 6:50 PM, Jim Davis wrote:
>> On Saturday, September 24, 2022 at 8:50:54 PM UTC-4, ABLE1 wrote:
>>> On 9/24/2022 7:35 PM, Bob La Londe wrote:
>>>> On 9/24/2022 9:49 AM, ABLE1 wrote:
>>>>> 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!!!
>>>>>
>>>>> Les
>>>>>
>>>>
>>>>
>>>> So inclusion a tin foil may actually stop the voices.
>>> LOL
>>>
>>> Only if the foil is placed properly in the hearing canal!!
>>
>>
>>
>> Â  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.
>> .
>> Â  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 ! !
>
>
> 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


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.



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