[TheList] APCO25

Sat Apr 23 19:56:12 AEST 2011

I was being terribly naughty, I used my gas soldering iron on the MDF 
(main Distribution Frame) at Mount Maunganui Exchange. The tech who 
arrived whilst I was doing so told me off and went into the switchroom. 
A few minutes later the VESDA went off, I glanced up and saw it was the 
switchroom and not the MDF's zone that had triggered and continued as I 
was. The tech came out and proceeded to rip me a new one, at which point 
I assumed he'd been smoking outside & just came in. It didn't take me 
long to see the smoke coming out of the switchroom. I applied the power 
contact warning notices to the MDF before heading into the exchange and 
starting to pull multiple line cards (there is more to that story, I did 
it properly, pity the other tech didn't, yet he being superior to me, 
did blame me and got away with it).

About 2 km's away 230/400V mains was in contact with a 100 pair cable in 
a fire.

All the MOV's on the line cards were erupting in flames.

It was an interesting day.

He never did apologise for falsely accusing me, I didn't mind, I was 
breaking the rules, but I knew I got an audible alert before it did 
anything drastic. Pity he didn't own up to his own mistakes though.

For those that don't know what VESDA is, it's a Very Early Smoke 
Detection Alarm. Pipes are installed that travel throughout buildings. 
Close to the VESDA unit the holes are smaller, further away larger, so 
each hole samples a similar amount of air throughout the whole building 
in a uniform manner. The air is passed through an extremely sensitive 
detector that's based on a radioactive isotope and detects products of 
combustion.

Funny the things you remember that previously you'd forgotten.

Thanks for prompting that Dennis.

Regards,

Neill.

On 23/04/2011 8:35 p.m., Denis Dawson wrote:
> I remember trying to set up a VESDA system at a TV site in OZ - far north
> Queensland.   When it went off it opened the main MCB and took out the whole
> site, several commercial TVs and lots of FMs. Took us ages to figure out
> there was a bushfire something like 20KMs away causing the smoke. Quick
> solution to sample the outside air first...
> Denis
>
> -----Original Message-----
> From: thelist-bounces at radiowiki.org.nz
> [mailto:thelist-bounces at radiowiki.org.nz] On Behalf Of Neill Ellis
> Sent: Saturday, 23 April 2011 7:37 p.m.
> To: zl1cop at qsl.net; thelist at radiowiki.org.nz
> Subject: Re: [TheList] APCO25
>
> LOL, or High Power on HF to set off Burglar Alarms. One of the local
> rouges hammered Tauranga to the point that just about all the alarms
> were replaced with newer equipment that had better immunity.
> Occasionally he'd go over to Rotovegas or Hamiltown and cause caos over
> there.
>
> Then there was the VESDA Fire Alarm in the telephone exchanges,
> temperamental at the best of times. Fire would check, reset the system
> etc. Last thing they'd do was call up on their handportable to say it
> was all good and they were on their way. Of course the burst of RF from
> that call just outside the door would often set it off again.
>
> Those were the days.
>
> Thanks for the stroll down memory lane Andy :-)
>
> Regards,
>
> Neill.
>
>
> On 23/04/2011 5:30 p.m., Andy wrote:
>> If that catches on it would be a great unintended benefit of the digital
>> radio system.
>> Imagine, all you have to do is press the mic button and every speeder
> within
>> range hits the brakes!!
>>
>> Reminds me of bit of some harmless fun indulged in by some young
> constables
>> back in the early 80s when space invader machines were the latest
> attraction
>> at the local takeaway.
>> These machines were a magnet for the local "yoof" on a Friday night,
> before
>> they moved on to their normal activities of syphoning gas and roaring
> around
>> pissed in mk2 Cortinas. It didn't take long to establish that the radio
>> suppression on these devices was not very effective to say the least. A
>> quick burst of 25 watts of carrier at around 78MHz from the innocent white
>> HZ Holden parked across the road was sufficient to blank the screen and
>> reset the machine so it said  "Game Over - Insert 20 cents ".  It was
>> amazing how much money they would feed it before realizing that something
>> was going on, especially if you gave them a couple of minutes of play
> before
>> hitting the button again. Every time they complained to the takeaway guy
> it
>> worked perfectly when he tried it. They never figured it out.
>>
>> Andy
>>
>>
>>    -----Original Message-----
>> From: Mike Barnes (ZL3TMB) [mailto:zl3tmb at ihug.co.nz]
>> Sent: Friday, 22 April 2011 10:35 a.m.
>> To: zl1cop at qsl.net
>> Subject: RE: [TheList] APCO25
>>
>> I know to slow down, and keep the $$ in my pocket :)
>>
>> -----Original Message-----
>> From: Andy [mailto:zl1cop at qsl.net]
>> Sent: Friday, 22 April 2011 12:04 a.m.
>> To: 'Mike Barnes (ZL3TMB)'
>> Subject: RE: [TheList] APCO25
>>
>> "A simple P25 buzz warns of the police near by....."
>>
>> And then what?
>>
>>
>>
>> -----Original Message-----
>> From: Mike Barnes (ZL3TMB) [mailto:zl3tmb at ihug.co.nz]
>> Sent: Thursday, 21 April 2011 11:00 p.m.
>> To: thelist at radiowiki.org.nz; zl1cop at qsl.net
>> Subject: RE: [TheList] APCO25
>>
>>
>> Hmmmmm, so if I enter all these frequency as mobile inputs in my scanner
>> with a very poor antenna.
>> I've just created the best radar detector ever :)
>>
>> A simple P25 buzz warns of the police near by.....
>>
>>
> http://www.rsm.govt.nz/cms/pdf-library/resource-library/publications/pib-23/
>> PIB23-Issue-6.pdf
>>
>> The simple ideas are the greatest.. :)
>>
>> Have fun.....
>>
>>
>> Andy wrote:
>>> Current state of play:
>>>
>>> Following freqs in the Auckland area observed as active with APCO P25
>>> trunking data:
>>>
>>> 141.1500
>>> 141.1750
>>> 141.2625
>>> 143.2750
>>> 143.3500
>>> 143.3625
>>> 143.3750
>>> 143.3875
>>> 143.4375
>>> 498.5125
>>> 498.5250
>>> 498.5625
>>> 498.6375
>>> 498.6625
>>> 498.6750
>>> 498.6875
>>> 498.7000
>>> 498.8125
>>> 498.9875
>>>
>>> cheers
>>>
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>>
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