MDC vs. QCII paging reliability

Post by **HumHead** » Sat Mar 09, 2002 10:02 pm

I am in the process of coordinating a new repeater based system for one of my amblance corps.

One of the changes that I am contemplating is a change from good old QCII two-tone to a complete MDC1200 paging / signaling implementation. It seems to make a lot of sense, but I'm unaware of anyone else running such a system. I don't know if this is due to sentimental / legacy equipment based attachments to QCII, or if there is a reliability issue that I'm overlooking.

My thinking is to use fleet calls for general dispatch, group calls for smaller groups (officers, etc.), and individual call alerts / select calls for individual signalling. We're also looking for the emergency signaling and radio check, even for radios in "pager mode".

I am already well aware of the following:
1) We already have an institutional philosophy of issuing only portables. We don't issue pagers, so pager compatibility is not an issue for us. (Ever try to call for backup on a Minitor?

)

2) We would be pretty much marrying ourself to Motorola for equipment. (We can live with that for the forseeable future)

3) I'm cheerfully assuming that Motorola will continue to support MDC1200 for the forseeable future.

Being an emergency service application one of my primary concerns is the reliability of signalling with MDC instead of QCII. I am drawn to the fact that it can work while in scan and, with a good pre-time or preamble, could force a scanning radio back onto its priority channel to receive an alert.

On the other hand, I don't know if MDC would be more or less reliable in terms of decoding in fringe areas, or through interference.

Thoughts / comments?

Thanks!

Nand · Post by **Nand** » Sat Mar 09, 2002 10:22 pm

Nickdap · Post by **Nickdap** » Sun Mar 10, 2002 3:08 am

Hi,
MDC i hear is very good with interfernce. more likly for the emergency signal to get through then a voice call for help in bad signal conditions.
nick

raymond345 · Post by **raymond345** » Sun Mar 10, 2002 3:29 am

HI there from Canada

Mdc 600 used by the Ontario Provincal
Police works very well.
(State)Provincal wide coverage cost $105 Million.
We are still working the MDC1200
signalling out of the local police
using the Ht1000 portables.They do not like
getting use to the pre delay, they complain
about it.

Chris · Post by **Chris** » Sun Mar 10, 2002 7:44 am

MDC is a far more robust protocol than any conventional analog tone system. It was built with error correction bits and does very well in fringe areas where a conventional tone decoder would not alert.

On the other hand, you are tied to Motorola for the most part, you can always get aftermarker boards, but none of them work as well as the integrated MDC systems in the Motorola radios. If and when Motorola does drop MDC1200, you are tied into an SP product if you can afford to keep them supporting you. Additionally, the MDC1200 alert burst will sound only slightly longer than a PTT-ID since the MDC Page is actually two data burts tied together so the familiar tones of your agency will be a thing of the past.

I can't recommend one thing over another here. MDC1200 is technically better, but two-tone is much more cost-effective, and widely accepted.

Chris

Nand · Post by **Nand** » Sun Mar 10, 2002 9:38 am

Chris · Post by **Chris** » Sun Mar 10, 2002 12:42 pm

Nand is correct, the post should read error detection to prevent falsing and misdirected calls.

KitN1MCC · Post by **KitN1MCC** » Mon Mar 11, 2002 6:38 pm

MDC does Go alot further in Simplex. i know i can hear MDC id's when i can not even heard the Voice.I can see the id's on my CDM1550 . also i can Decode displays from NYC here in Ct on the bass. when the printer is hooked up it just has pages of id's

also u can keep a log who is on the air ad when and also can do message and staus info