I need to correct one of your myths:
BUT, if you have a larger system, with multiple transmitters per channel, working simultaneously, it gets much more complicated and much more expensive. It's not a brand thing, it's physics. The tolerances on mixing a signal on the air gets much more difficult when the signals are narrowbanded. Twice as many towers isn't too far off of an estimate. More rent, more equipment, more circuits, much more money. That that doesn't change no matter what vendor you choose. What might change is how much you pay up front versus in change orders later to get the system to work right.
If your trunking or conventional system covers a very large area, there's a good chance you're using simulcast. Before you tell everyone it's just a matter of programming some radios, find out if you use simulcast.
Before this gives Simulcast a bad name, it's an excellent technology for public safety radio. When you would normally start to hear static from the repeater in a single TX system, simulcast helps fill in the gaps so you rarely lose signal. The only downside is the cost to narrow band it.
The real problem, IMHO, is that the FCC let everyone and their brother pee in the Public Safety Pool and now they wonder why it's overflowing. When my Fire Department has to share channels with school buses and plumbers, something is wrong with the system. Not the radio system, the FCC's system of frequency management.
Most conventional systems with multiple transmitters in a wide area are one-at-time selectable by the dispatcher or with a site-steering capable comparator. A true conventional simulcast system is very rare.
If you happen to have a mountain in your territory, a single site transmitter could be a good match and easy narrow banding. But if you're relatively flat, urban or need good building penetration, Simulcast is a great solution.
If you have multiple transmitters and your dispatcher manually switches them, or have steering, narrowbanding will make upgrading later very expensive also. I think if you ask anyone that went from one transmitter at a time to simulcast, they won't ever want to go back. I know we never will.
All very true.... as long as you have the checkbook big enough to fund all the required infrastructure for it. Which is why it is still rare. It may be not as rare, but still rare.
Well we have our meeting with motorola last nite chief and asst chief county meeting and told them what we new and what they were trying to make us buy was going to happen. So to make a long story short they told us that they owned the 154.220 and all of our other channel's and we are going to buy what they want us to buy or we ant going to have any channel's. Now to tell you all qho they think the own our channel's is they fill out the paper work for the county dispatch. Well they didn't to there home work because every fire department in the county has there on license for the channel's we use and we all have our on call letter's to kinwood just sold the entire county a new highband system for police fire and ems now only if they sale pager's.
I have no clue wtf most of that is supposed to mean. However what little I could gather from it, Motorola is lying, they trying to scam you. Do not listen to them. Everything that I and Res343cue have said still stands.
I will jump in for a bit.
We run a county wide dispatch system that uses four primary frequencies Paging currently wide band simple repeater system , Police Multi-cast narrow band, EMS Multi-cast narrow band and Fire also multi-cast narrow band.
We have been running our Law and EMS frequencies as a wide band multicast system for a number of years 10 + on Law and 5+ on EMS with pretty decent results some dead areas in the fringe we are a long narrow county with water all around lots of bluffs and remote Islands.
Three years ago we were lucky to receive an AFG grant to rebuild our fire communication system, this system at the time was a simple repeater system, and the upgrade was to bring it up to a multi-cast system. Part of that upgrade was to also narrow band our existing Law and EMS frequency.
As we moved to the narrow band system we saw a significant increase in the size of our fringe areas due to reduced coverage when narrow banding was put in place. We have been very fortunate to be able to build out our Fire System with several additional receive only sights that do not support EMS and Law, and the difference is noticeable for us. Many areas Fire can get into dispatch with a portable where the Law and EMS standing alongside of us cannot get in.
Radios are soup to nuts Motorola, Icom , Kenwood , and Vertex. What we found in a significant portion of the radios we owned was that yes they could technically narrow band, but there were many frequencies the radio would simple not accept we found this across all manufactures. In other words if a radio could take freq 123.456 then it could take 123.4560 but not 123.4565 not sure if that makes sense to all of you, but they could not take the new in between frequencies only the narrow band of the old frequencies.
As to pagers we have a mix of Minitor 3/4/5s most are set up with dual channel and scan. As of now paging channel has stayed wide band so we have no issues there when we scan the other frequencies (EMS pagers scan EMS Fire Pagers scan Fire) there is some noticeable reduction in volume and quality.
Over all we are happy with our upgrades and are hoping to be able to upgrade the paging system to a simulcast system.
I thought I would post this incase anyone would like to check it out.
This guy is an excellent resource for anyone buying, thinking about buying, spec'ing, or just worried if they are going to comply with the new communications standards. He is giving free seminars at various venues (although there may be a cost for the venue itself in some cases, or your 911 director can help you get in) throughout the US.
He is an attorney. Get the jokes out, I have never seen any other attorney have the grasp on the technical issues related to communication like he does. He even pops up here on Firehouse from time to time. Anyone wanting to stay out of trouble would be really smart to attend one of his seminars. His information is below his spring schedule.
Or you can listen to salespeople, and read misinformed articles.
IWCE - March 8-12
Indiana NENA - March 25
Alabama APCO - March 30
Arkansas APCO/NENA - March 12-13
New Jersey NENA - April 20
Texas APCO - April 26
APTA Bus & ParaTransit - May 3-5
PA APCO - May 17-19
More to come!
Alan S. Tilles, Esq.
Chairman, Telecommunications Department
firstname.lastname@example.org | T 301.231.0930 | F 301.230.2891
SHULMAN, ROGERS, GANDAL, PORDY & ECKER, P.A.
12505 PARK POTOMAC AVENUE, 6TH FLOOR, POTOMAC, MD 20854
Areas that are flat may see little coverage loss with Narrow banding, But in our area we have been testing and our portables are almost worthless other then line of sight we had a 30% or greater loss of coverage we have had to add repeaters in our trucks just to hit our towers we have been raising antennas replacing radios and trying to add repeaters and I hope when it all done its worth all the money and effort
That is highly unusual. Something more than just changing to 12.5khz modulation took place to reduce your coverage that much. What else changed?
I wish someone could tell me and we would save a lot of cash. but so far no other reason has been found and except in areas where we had issues before the truck repeater system allows our portables to get out.
Sorry if all of this free information is considered hucksterism. I thought that I was doing the right thing. BTW, I've not asked to be paid for the dozens of APCO and other association meetings where I've done narrowbanding presentations this year and in previous years.
I'm a sceptic when anything Motorola appears. But apprently they selling a bunch of Mototrbo in the area to businesses and gov't/state agencies (not public safety).
What's the scoop on Mototrbo? Some proprietary M system that won't play with anything else. Not public safety appropriate?