Got my lesson in Analog vs Digital

[RickS31]

Have just setup and played with both the Atlanta P25 digital system and the Fulton County Mot 800/900 analog system. Something I'm sure most folks on here know but for me helps to see it for real. Saw the distance equation for the Atlanta system make it mostly unreadable for about 30%+ of the VCs. Programmed in the Fulton County analog system in another scanlist and was able to track accurately all of the voice comm. out of Lawrenceville and whatever repeaters they have. Not always perfectly clear but always readable and trunkable.

Having been in radio for many years through the cell phone environment when it went from analog to digital, you know this down in your gut but it's always fun to actually see the difference in action.

Rick

 

[MTS2000des]

Have just setup and played with both the Atlanta P25 digital system and the Fulton County Mot 800/900 analog system. Something I'm sure most folks on here know but for me helps to see it for real. Saw the distance equation for the Atlanta system make it mostly unreadable for about 30%+ of the VCs. Programmed in the Fulton County analog system in another scanlist and was able to track accurately all of the voice comm. out of Lawrenceville and whatever repeaters they have. Not always perfectly clear but always readable and trunkable.

Having been in radio for many years through the cell phone environment when it went from analog to digital, you know this down in your gut but it's always fun to actually see the difference in action.

Rick

Much of that has to do with the performance (or lack of) of digital scanners on simulcast digital systems. Motorola uses CQPSK not C4FM, and current digital scanners cannot properly handle it.

I'll give you a comparison. My work issued XTS2500i on the Cobb DTRS is able to hear (and affiliate) on the system from as far south as Newnan. On a Pro96, you lose it just past the I-20 interchange. I was actually inside the casino at the dog track at Victoryland in Shorter, AL and the Cobb DTRS starting unmuting. I got the "No COMMS" message as the radio could not reach the site, but it was hearing the CC. Once it did and affiliated, I was hearing MFD well inside Alabama. Kind of wierd.

A "real" radio almost always has a better front end than any scanner, be it digital or analog. A couple years back I recall being able to access the Fulton TRS in Helen at Mountain Lakes. This was using a Motorola STX821E.

Digital can be quite better than analog in some cases. For example, the Cobb DTRS is good to about the Alabama line on I-20 until it starts "going digital", the analog system would get weak and unusuable just outside of Carrolton.

 

[rmiller818]

And yet there seems to be a few locations inside the county where the users just don't get good performance.

I really wish someone would make a scanner specifically for digital systems that was based on the way real subscriber radios work. Or maybe just buy a real radio and program it for receive only.

 

[RickS31]

It would be nice if the scanners had the sensitivity and selectivity of their commercial counterparts. But, these scanners are not built or designed to be life saving communication links. The cost would put them out of reach of most of us hobbyists. Also, since most of the commercial radios have only a few frequencies to receive (or transmit) on, they can be totally optimized just for those. Again, a big difference in design.
IMHO I think these scanners do a great job of covering all the ranges, modulation types and trunking decoding that they do without being a $1K+ unit. But I agree, I think we'll see more and more improvements on all the above as time goes on.