VHF Narrowanding - Anyone done it yet?

[MESDA6]

I'm working on the logistics of our narrowbanding and am looking for feedback from those that have done it. Our frequency is in the 155.xx range and I understand there can be a significant drop in radio range when narrowbanding. The area is basically typical midwest, wide open cornfields with no real obstructions, and we are probably looking at an average range of 8-15 miles when we need to communicate.


We use both base-to-mobile and mobile-to-mobile comms. Portables are only used on scene and in short range. The mobiles are 45 or 50 watts.


So, for those on VHF Hi who have narrowbanded:


1. What kind of range drop have you experienced?


2. Did you add a repeater into your system or feel that you should have?


3. Anything else that needs to be taken into account?


Thanks!

 

[Brian H]

We narrowbanded in January freq ranges from 151-158. We already have to use repeaters in our area due to terrain and tower placement but we have been fine ever since. No real problems discovered other then you're going to find a lot of radios that no one knew existed or someone "forgot" they had.

 

[fleetcomm]

I'm working on the logistics of our narrowbanding and am looking for feedback from those that have done it. Our frequency is in the 155.xx range and I understand there can be a significant drop in radio range when narrowbanding. The area is basically typical midwest, wide open cornfields with no real obstructions, and we are probably looking at an average range of 8-15 miles when we need to communicate.

We use both base-to-mobile and mobile-to-mobile comms. Portables are only used on scene and in short range. The mobiles are 45 or 50 watts.


So, for those on VHF Hi who have narrowbanded:


1. What kind of range drop have you experienced?


None, in some cases better coverage. we also have 45 watt mobiles.


2. Did you add a repeater into your system or feel that you should have?


Changed repeater because the old one would not narrowband.


3. Anything else that needs to be taken into account?


Make sure on your radio count of any that need to be replaced.


buy a good repeater (Kenwood or Motorola) that has a good service shop in your area.


If you are going to replace most of your radios you may want to look into Nexedge or mototrbo radios, the repeaters cost the same and you will get 2 channel out of the one you have now. The other thing is scanners will not pick them up. If you use one of these systems you will see alot of radios show up that were not accounted for before.

 

[Respondcode3]

I wouldn't recommend Nextege or Mototrbo for public safety use. Mutal aid and interoperability...

 

[fleetcomm]

I wouldn't recommend Nextege or Mototrbo for public safety use. Mutal aid and interoperability...

I would agree, I don't like the part of not having interoperability but, You get alot of bang for your buck and lots of departments are using them. The department with the nexedge or mototrbo can talk to other departments but, those department can not talk on your channel.

 

[SlickTop Solutions]

I'm working on the logistics of our narrowbanding and am looking for feedback from those that have done it. Our frequency is in the 155.xx range and I understand there can be a significant drop in radio range when narrowbanding. The area is basically typical midwest, wide open cornfields with no real obstructions, and we are probably looking at an average range of 8-15 miles when we need to communicate.

We use both base-to-mobile and mobile-to-mobile comms. Portables are only used on scene and in short range. The mobiles are 45 or 50 watts.


So, for those on VHF Hi who have narrowbanded:


1. What kind of range drop have you experienced?


2. Did you add a repeater into your system or feel that you should have?


3. Anything else that needs to be taken into account?


Thanks!

The biggest thing I have seen with units going NB with existing radios, is tuning. A radio may work great WB, but suck and appear to have less range when NB activated in the same radio. In all cases, having a qualified radio tech with the right gear retuning the radios to spec (or better) has cured any issues.

 

[Lookn2cuff]

I'm working on the logistics of our narrowbanding and am looking for feedback from those that have done it. Our frequency is in the 155.xx range and I understand there can be a significant drop in radio range when narrowbanding. The area is basically typical midwest, wide open cornfields with no real obstructions, and we are probably looking at an average range of 8-15 miles when we need to communicate.

We use both base-to-mobile and mobile-to-mobile comms. Portables are only used on scene and in short range. The mobiles are 45 or 50 watts.


So, for those on VHF Hi who have narrowbanded:


1. What kind of range drop have you experienced?


We used to get coverage about 50 miles away, but barely hit the county repeater anymore. Even at 30 miles away it's hard to hit. Of course we have a lot of hills in the Hill Country of Central Texas.


2. Did you add a repeater into your system or feel that you should have?


Did not add any repeaters, just reprogrammed the one we already had.


3. Anything else that needs to be taken into account?


Older wide band radios will still work on the system. If they're too old, get new ones. It's always better to get the stuff out now, not neccessarily the lastest and greatest, but much newer radios. We have had a lot more skip from further away and sometimes can't get good transmission out of buildings. The main tower is about 1/4 mile away from the Sheriff's Office and EMS Station...

 

[fleetcomm]

The biggest thing I have seen with units going NB with existing radios, is tuning. A radio may work great WB, but suck and appear to have less range when NB activated in the same radio. In all cases, having a qualified radio tech with the right gear retuning the radios to spec (or better) has cured any issues.

Very good advice,this is what I have saw with narrowbanding also.

 

[MESDA6]

Thanks for all of the responses. Good to hear that there are positive results out there.


We have not had the need for a repeater, but might be leaning that way now since we can include it in the budget for narrowbanding. This would also allow us to utilize our portables for paging and better functionality with the increased range.


Going to Nexedge or Motortrbo is not an option. We work with numerous jurisdictions and have the need to have their VHF frequencies in our equipment, and they have our channels in their radios as well. VHF Hi is in extensive use throughout the state, even though there are state and local P25 systems available. Smaller agencies do not have the budgets to get on them, or stay on them due to the high cost.


We literally have to replace every radio, including the receiver boards on the sirens to meet the narrowband mandate. Our current equipment was purchased in the mid-90s and is not able to be tuned accordingly. The cost to re-tune the siren boards is comparable to purchasing and installing new boards when you factor in de-installation, re-tuning cost by the factory, and re-installation. Plus, it would leave us without sirens while the boards are at the factory, so it's not really an option.


I hadn't thought about the radios that will come out of the woodwork. We will thank them for the return of the stolen property. :haha:


Thanks again for the responses.

 

[Respondcode3]

What kind of portables are you using now?

 

[MESDA6]

What kind of portables are you using now?

A mix of Maxons and some very old Motorola units. I have 2 motorolas that I can narrowband - the rest aren't capable. We will be including new portables in our requirements, and add some features that the current ones don't have, primarily 2 tone encode and decode for paging and siren activation.

 

[Fast LT1]

Get new ones! Like icoms or kenwoods! Also I would add a repeater for sure!

 

[theroofable]

Thanks for all of the responses. Good to hear that there are positive results out there.

We have not had the need for a repeater, but might be leaning that way now since we can include it in the budget for narrowbanding. This would also allow us to utilize our portables for paging and better functionality with the increased range.


Going to Nexedge or Motortrbo is not an option. We work with numerous jurisdictions and have the need to have their VHF frequencies in our equipment, and they have our channels in their radios as well. VHF Hi is in extensive use throughout the state, even though there are state and local P25 systems available. Smaller agencies do not have the budgets to get on them, or stay on them due to the high cost.


We literally have to replace every radio, including the receiver boards on the sirens to meet the narrowband mandate. Our current equipment was purchased in the mid-90s and is not able to be tuned accordingly. The cost to re-tune the siren boards is comparable to purchasing and installing new boards when you factor in de-installation, re-tuning cost by the factory, and re-installation. Plus, it would leave us without sirens while the boards are at the factory, so it's not really an option.


I hadn't thought about the radios that will come out of the woodwork. We will thank them for the return of the stolen property. :haha:


Thanks again for the responses.

The sirens most likely will still activate without having them changed to narrowband. I know ours still works without narrowbanding it. You should test it before you change it.

 

[Brian H]

The person who NB our radios said that civil defense sirens don't technically need to be reprogrammed because they recieve only and not transmit. Whether that is true or not I don't know the 100% sure answer. I will say that where I live we have 5 new Fed Sig sirens that were narrowbanded and 4 other towns that have not been Nb and they all worked for the first saturday of the month test

 

[MESDA6]

The person who NB our radios said that civil defense sirens don't technically need to be reprogrammed because they recieve only and not transmit. Whether that is true or not I don't know the 100% sure answer. I will say that where I live we have 5 new Fed Sig sirens that were narrowbanded and 4 other towns that have not been Nb and they all worked for the first saturday of the month test

It appears to be kind of a toss up. Ours are receive only, but not all are. In larger cities and counties, many of them use a 2 way board to report that they activated. My thought was that ours will most likely still work without re-programming, but no one here is willing to take a chance on them not working when they are needed most. Given all of the various atmospheric factors that seem to affect the radios during a storm, it will be very hard to explain why we didn't re-band them if they don't activate during a real event.


The total cost to re-band the sirens is about equal to buying 1/2 a siren. Not re-banding them could cost hundreds of thousands, or millions in litigation if they fail to activate during a real tornado event. It's just not worth it to save a few bucks.

 

[theroofable]

Didnt think of that. We dont use ours for storms. I narrowbanded one of my portables, and it communicates with everything that is wide fine, including various repeaters on dpls. I have not noticed any reduction in quality of communication. Just thought it was worth mentioning.

 

[MESDA6]

Didnt think of that. We dont use ours for storms. I narrowbanded one of my portables, and it communicates with everything that is wide fine, including various repeaters on dpls. I have not noticed any reduction in quality of communication. Just thought it was worth mentioning.

I appreciate the feedback. Ours are only used for Tornado Warnings or might be used if there was some major incident with a significant public hazard, but so far only used for Tornado Warnings.


It's one of those things that I think would probably be fine if we left it as-is, but I also don't want to be responsible for that one-in-a-million event where it doesn't work as it should. The surrounding counties are narrowbanding theirs, so it seems like we should follow suit.


Thanks again.