mdc-1200 siren alerting

Gocart878 · Post by **Gocart878** » Thu Apr 06, 2006 6:38 pm

ok so here it goes, we have a fairly large federal signal siren in a remote location in our fire district. i know i have talked about this before, but please feed me more input. so, our fire dispatch uses the mdc-1200 horn/lights signalling to alert all sirens in our surrounding fire district. the fire siren makes two different signals, a wail and a fast wail. the siren control requires that one tone sets off each signal. thus two motorola mobile radios are needed.

i am going to buy 2 cdm-1250 radios with full signalling capabilities, seeing as these radios will be used on a recieve only basis and locked in a Nema 4 weather tight box, i figure i can use one power supply to support both radios.

they are 25 watt radios, in the UHF 420mhz split., the only time the radios transmit are when the radio sends a confirmation tone back to the fire dispatcher to verify the mdc tone was infact recieved. only one radio will ever transmit at a time. what size power supply should i need? also am i ok with tieing both radios into one supply? should i fuse the power to the radios? what amp fuse?

what do you guys think of this, any other precautions, how about antenna mounting, whats the minimum distance apart the two antennas can be placed?
thanks for all your help./

michael

thebigphish · Post by **thebigphish** » Thu Apr 06, 2006 8:03 pm

Why use two radios? All your radio is decoding is MDC packets right? Selective IDs? Assign the Aux Output pins, one for each wail speed to the separate MDC IDs, assign it under System Config and set up the output to latching or momentary or what ever you need....unless you really need the radio to tx back to dispatch (with a good install and a good antenna set up, you shouldn't have to worry about it NOT RXing it - unless your system's protocol requires you to get an ACK)...
At least as i see it, you can have that radio just sit on one channel and wait for MDC to fly its way...

this is all speculation from someone who has used every other aspect of a CDM, except for the accessory signalling options

jim · Post by **jim** » Thu Apr 06, 2006 9:14 pm

Won't work as a single radio. There's only one output on the Waris series for all signalling. He needs 2 radios.

Does dispatch support DTMF? Midian makes an 8 channel decoder board that will support 8 events and outputs.

As for TX, a 7A will work fine for a 2 second tranmit cycle acknowledge signal. Run as low power as necessary as no more than this is needed.

Gocart878 · Post by **Gocart878** » Fri Apr 07, 2006 3:33 am

yes, dispatch supports dtmf and quik call. but the fire dispatcher doesnt seem to like the idea of assigning anything other than the mdc-1200 tones. personally, i have a small veetronix alert reciever that has everything already in it. it works great on dtmf and quik call. however it doesnt support mdc. i have looked at the cimeron boards and it seems way to complicated for this current situation. i will keep you posted, anyways for two cdm 1250's the local M dealer quoted me 537$ per radio. what do you think of that price?

thebigphish · Post by **thebigphish** » Fri Apr 07, 2006 3:43 am

ahh, i was not aware of the single signalling output...good to know jim, thx. I will have to experiment with this section of the CPS and the radio now, to see what does what.

Gocart, this is one of the places where you show them how well DTMF works and how you can lower the equipment overhead, and lessen the # of moving pieces by switching to DTMF signalling, rather than MDC-1200. It always is a hassle when the establishment is stubborn to change...

jim · Post by **jim** » Fri Apr 07, 2006 5:57 am

Seperation....

Use low power with 5-element Yagis. Vertically seperate them approx 10' if possible. To mount them is diffucult to say without seeing the setup.

Why not use a CDM750 for the one in the NEMA enclosure.

If you didn't need to acknowledge, you could use one radio with a Cimmaron decoder board for the second MDC decode.

I try to stay away from MDC for siren activation. QCII is the most reliable compared to anything- sepecially digital.

jackhackett · Post by **jackhackett** » Fri Apr 07, 2006 10:48 am

jim wrote:Won't work as a single radio. There's only one output on the Waris series for all signalling. He needs 2 radios.

I must be missing something here.. you mean he couldn't set pin 4 as Aux Control 1, pin 8 as Aux Control 2, and then set the Aux Control Active IDs each to a different number? I've never tried this, but it sounds like it should work. It would be kind of silly for Moto to put two Aux Controls in the radio if you could only use one, but then it is Moto we're talking about so anything is possible.

thebigphish · Post by **thebigphish** » Fri Apr 07, 2006 11:10 am

jackhackett wrote:
jim wrote:Won't work as a single radio. There's only one output on the Waris series for all signalling. He needs 2 radios.
I must be missing something here.. you mean he couldn't set pin 4 as Aux Control 1, pin 8 as Aux Control 2, and then set the Aux Control Active IDs each to a different number? I've never tried this, but it sounds like it should work. It would be kind of silly for Moto to put two Aux Controls in the radio if you could only use one, but then it is Moto we're talking about so anything is possible.

that's exactly what i thought, unless those outputs are only for DTMF control, which i really can't fathom why they would limit them (although we have seen stranger).

Lake Effect · Post by **Lake Effect** » Fri Apr 07, 2006 12:35 pm

I tried the aux output idea on a cdm1250 on the bench and it works ok for the output. Only problem is it doesn't send ack message. When I send the regular call alert, the 1250 will ack. Just not on the aux control ID.

L.E.

jim · Post by **jim** » Fri Apr 07, 2006 2:12 pm

That's what I thought too but it has never worked. I've tried over and over and could never get it to do a second output. There is no way to assign the second output to a second tone.

The first (pin 4) will default when a call comes in, but the second will not.

Hmm.

KitN1MCC · Post by **KitN1MCC** » Tue Apr 11, 2006 1:00 pm

i would say use DTMF That What Whelen has used thats since they started in the siren business and it is a lot simpler set up or Quik call

Go cart were are you located

jim · Post by **jim** » Tue Apr 11, 2006 7:29 pm

"i would say use DTMF That What Whelen has used thats since they started in the siren business and it is a lot simpler set up or Quik call "

Dude....take some grammar and English lessons for that sake of all of all educated persons on this forum.

DTMF is unreliable for call alerting. There are too many factors that cause problems. We see more errors in decode/encode with DTMF call alert systems- especially the WHELEN and FEDERAL proprietary systems. Don't waste your time with DTMF. QCII is the most reliable. Obviously, you don't work in the field to say something like what you did. QCII is diffucult? Um... Tone A. Tone B. End of story.

thebigphish · Post by **thebigphish** » Tue Apr 11, 2006 8:42 pm

jim wrote:Dude....take some grammar and English lessons for that sake of all of all educated persons on this forum.

hahah, he's spent too much time at the flooded 'America's Cup', and now has river-water toxicity...it's ok, it's normal.

RFguy · Post by **RFguy** » Wed Apr 12, 2006 5:32 am

I thought it was just me with the Aux outputs.
1) Why no acknogledgement? Makes this feature nearly useless.

2) Why do they ony have 1 output that can actually drive a relay? The other outputs are logic and dont have the drive to drive a reay (maybe a reed type, but nor a Bosch type).