Wideband vs Narrowband vs Digital.

[12dbsinad]

I would like to ask the Forum members there personal experience of the conversion to Narrowband or the conversion to digital land mobile radio. The radio shops around here (and everywhere) are going to town with the whole narrowbanding thing and misleading information. In terms like, "you will loose 6 db of coverage going to narrowband analog... in order to replenish that you will need to go digital." Umm yeah okay... But anyways, What are your thoughts?

 

[N4DES]

I found a few mile reduction in recoverable audio when we narrow-banded our UHF EMS system when using a portable radio outdoors (mobile wasn't affected as bad). Now we use single site TX and multiple satellite receivers, so my basis for stating the above was on talk-out and not talk-back. The reduction in modulation gives the impression of a much higher noise floor at areas past the 20db quieting point of the receiver.

As to the digital vs analog, it is pretty well proven that the "quality" of a transmission out to the 12db SINAD point, with all things being equal, is much better in the digital world. It doesn't make you talk further, but the audio quality is so much better to the edge.

 

[W8RMH]

I would like to ask the Forum members there personal experience of the conversion to Narrowband or the conversion to digital land mobile radio. The radio shops around here (and everywhere) are going to town with the whole narrowbanding thing and misleading information. In terms like, "you will loose 6 db of coverage going to narrowband analog... in order to replenish that you will need to go digital." Umm yeah okay... But anyways, What are your thoughts?

They make a heck of a lot more money selling a new digital system than they do reflashing your old radios or selling new radios for the current system. Like new car dealers. They would rather sell you a new car than repair your old one. But I do have a problem with them providing false information to do it.

 

[jhooten]

KS4VT,

I'm curious, did your system get replaced with new equipment or was the old equipment reprogrammed?

On a system around here the first tech came out and just reset the bandwidth with the programming software called it all good and left. The agency complained of poor coverage and low audio after the change. A second, more experienced tech was dispatched to troubleshoot the system. He did a realignment including setting audio levels on the repeater. System performance after the realignment was equal of perhaps even a little better than before the change. Mobiles and portables were checked during the normal PM schedule.

 

[N4DES]

Same UHF transmitters but the Spectra-TAC satellite receivers and voter/comparators were replaced and the whole system was re-aligned.

Audio levels remain constant in the areas where there is full quieting of the receivers, but out in the fringe areas the noise floor rises faster in the narrowband configuration.

 

[baycomm]

Narrowband/Wideband/Digital

We have wideband, narrowband & NXDN systems all operating from the same site with all channels combined into the same antenna. Output power of all channels is within 10 watts of each other.
These are our observations over the past year or so:
Using the wideband "legacy" system for comparison:

Narrowband analog does not provide usable coverage in weak signal areas that do have coverage on the wideband system. However, overall range is about the same & limited by topography. The narrowband has noticeably more dead spots.

NXDN at 6.25Khz again provides about equal overall coverage but with many fewer dead spots and is usable right to the edge of our coverage area with no decrease in audio quality. Furthermore, portables work in many places that were not usable at all in analog. For example from the inside of buildings and vehicles.

Yes we do try to sell customers digital radios because of the above comparisons. The cost difference between a good quality analog radio and a good quality digital radio is negligible, usually $50.00 or less. For example between a Kenwood TK-8180 and a NX-800. Given that the NX radios do everything the analog radios do plus a lot more why not buy the digital radio? This comparison only breaks down when comparing digital radios to low end analog radios. If all you need is a $200.00 portable stick with analog.

 

[12dbsinad]

Thanks for all the posts so far! I will give you my 2 cents... what the heck

Digital: I am saying digital in a (broad) form including p25, NXDN, IDAS, etc. I think the "newer" technology is way better than the standard that makes the cost of public safety syetems skyrocket. I think you all know what i mean. Anyhow, I think the spectrum effieciency and encryption options are nice. Digital offers clear comms throughout your coverage area, neat gps capability... etc...

Good old analog: Well im in my middle 30's and I wouldnt really consider myself old school... yet lol. Analog still has a place in my heart, and many others. On a fireground scene, you still cannot even compare the audio quality between analog and digital with a nice clear signal. At least that is just my personal opinion. You cannot get better audio quality than hearing your natural voice. Digital is more difficult to troubleshoot. When a mobile radio doesnt work well in the field, what is it? is it low RF power? severe altenator whine? Is the repeater or voter getting hammered with co-channel interference? You have no idea. In analog I can plug the channel in and listen for about 10 mins and say yep, that truck needs a DC noise filter installed, or wow the lift is up on UHF this morning big time!

I love both technologies and work with both. Those are just some of my veiws on each! Keep the posts coming!