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Input needed: Low band NEW multi-user system

This forum is for discussions regarding System Infrastructure and Related Equipment. This includes but is not limited to repeaters, base stations, consoles, voters, Voice over IP, system design and implementation, and other related topics.

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w8cmi
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Joined: Tue Oct 12, 2004 7:17 pm

Input needed: Low band NEW multi-user system

Postby w8cmi » Thu Jan 25, 2007 8:25 pm

I'm working with a rural county. About 450 square miles, rectangular shaped, county seat in the middle, various cities and towns throughout the county, rolling hilly topography with a few REALLY cavernous hollows and valleys.

Right now, public safety radio is a hodgepodge. The cities all run VHF simplex or repeater stations, a few with horrid input/output issues, and most with no more than 40 watts RF output. The sheriff has a 110 watt VHF repeater with a remote receiver. They dispatch two part-time village police agencies (one car each) and have two or three county cars on the road at any time. No vehicular repeaters anywhere in the county.

Fire: One department uses VHF Low (33 MHz), the "county" fire dispatcher uses a UHF local government repeater with about 70% portable coverage, and one department is on a 50 watt VHF high band repeater.

The county road department uses 37.98 and a 453 MHz highway maintenance repeater. Base to mobile coverage on UHF is about 85-90%, low band is countywide but the channel is shared with a much larger highway department about 30 miles away, so interference routinely kills them. School buses either use CB radios or have a 460 MHz business band repeater system with decent coverage.

No other county or township agency has any radio communication at all.

We'd like to standardize everything as much as possible, for interoperability, homeland security, and just plain old common sense communications. This project is dependant on money, but the county formed a technical advisory board (I am a member) and things are moving ahead slowly.

As you might imagine, the politics of radio system design are quite interesting. Most agencies feel they have a good radio system and want everyone to "standardize" on their band. I am looking at a different direction.

Low band. Specifically, 45-47 MHz.

I've worked this out on paper, and here's what we would probably need:

1 - Sheriff dispatch
2 - City #1 police dispatch
3 - City #2 police dispatch
4 - Police tactical common
5 - Fire dispatch
6 - Fireground
7 - Emergency Medical Service and Rescue
8 - EMA/Disaster
9 - County road department
10 - County government common
11 - City #1 public works
12 - City #2 public works
13 - Township road and maintenance common
14 - School District #1
15 - School District #2
16 - School District #3

From searching the FCC files, there are dozens of frequencies available in the 45-47 MHz band on the old Police, Fire, Local Government and Special Emergency assignments. Most were never used in this area, even back in the day, and all those agencies 50-100 miles away that did use these frequencies have migrated to high band or UHF.

Even with narrowbanding, there are precious few VHF and UHF repeater pairs available. So may of our surrounding counties have scarfed up a dozen or so new channels ... thete just isn't a lot left to pick from.

I have always been a low band fan of sorts, especially for rural, hilly areas. I really like the stand alone design of low band, where mobiles and base stations operate on their own stick and steam, and aren't dependant on a trunking network or a repeater station for wide area coverage. In a disaster situation, you just can't kill 'em.

I'm leaning toward mobile repeaters in law enforcement vehicles, fire trucks, and ambulances, with UHF portables capable of "one hop, two hop" operation where the PAC-RT can be bypassed for on-site communication, but the operator can still monitor the dispatcher and not get "lost".

Has anyone else put together such a proposal? Do you foresee any problems? I am concerned about equipment availability, especially since most manufacturers have essentially given up on 30-50 MHz.

Ideas? Comments? Rotten Tomatoes to throw at me?

:lol:

RocketNJ
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Postby RocketNJ » Thu Jan 25, 2007 9:48 pm

What brand/model base stations are you considering?

Damn the Micors were good. Last forever.

w8cmi
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Postby w8cmi » Fri Jan 26, 2007 4:13 am

RocketNJ wrote:What brand/model base stations are you considering?

Damn the Micors were good. Last forever.


Probably the MA/COM Orion for primary bases, if they're still available in low band. 110 watts with all the bells and whistles, and they come configured to be a REAL base radio. I doubt there's much more out there. I think Moto stopped making low band bases with the MSF5000 series.

We would probably do some tabletop bases (mobile on power supply) at fire stations, township garages, etc. Probably with DB201 folded dipoles at all base installations.

And yes, the Micors were indestructible.

8)

Jim202
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Postby Jim202 » Fri Jan 26, 2007 4:36 am

Your first problem is money.

Your second problem is fining a low band radio still being made.

Your third problem is getting everyone to agree.

Your forth problem is money. See problem number one.

Your fifth problem is a radio shop that can still fix low band
radios. Most of them have become radio swap out geeks.

Your sixth problem is still obtaining low band base antennas.

Your seventh problem is money.

Most public safety agencies are just barely able to make it
through the year with the funds they can obtain. When I
go out on road trips to give classes on radio interoperablity,
the first issue that comes up is how can we afford to purchase
the equipment. The answer is not easy. I tell them to go
after every program they can find for grant money. Next
have a meeting with the local District Attorney and see
what their feeling is on taking drug seisure property and
money to fund the new radio system. This way the whole
community is involved with supporting the new radio
system. Just get the drug task force to step up operations,
get the DA to speed up prosecutions and the court to do
what they should be doing.

You might also want to look at some good system engineering
help from a consultant. This way your not the bad guy and
have some solid documentation to support why your
spending all this public money on a new radio system.

Homework and public involvement is the key to success.
You will always have people in the community saying that
these new radios are not needed. Just keep the public
informed. Make a game plan. Keep the information in
the local news and papers. It might not seem like all
the publicity is needed. Just remember, if the public
knows what, why and when, they will always support
improvements to their public safety agencies. If you
spring a big project on them without them being informed
along the way, you will never get their support.

Jim

Grog
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Postby Grog » Fri Jan 26, 2007 4:59 am

Jim202 wrote:
Next have a meeting with the local District Attorney and see
what their feeling is on taking drug seisure property and
money to fund the new radio system. This way the whole
community is involved with supporting the new radio
system. Just get the drug task force to step up operations,
get the DA to speed up prosecutions and the court to do
what they should be doing.


Making arrests for profit is never a good thing :roll:

USPSS
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Postby USPSS » Fri Jan 26, 2007 8:04 am

Kenwood makes Low Band Mobiles, Portables, Base and Repeaters used by many State Patrols, Highway Patrols and the like nationwide.

Contact them since they are the largest Public Safety Low Band Player.
Stan Glass


Government & Entertainment Division Manager (Kenwood)

w8cmi
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Postby w8cmi » Fri Jan 26, 2007 8:07 am

Jim202 wrote:Your first problem is money.


Agreed. We're supposed to be getting a percentage of sales tax money to fund the changeover. Something will change and new radios will be purchased. It's just a question of what frequency band we'll use. Very little of the existing equipment is narrow band capable, so we'd probably need to replace existing radios anyway.

Jim202 wrote:Your second problem is fining a low band radio still being made.


Low band mobiles are no problem. Fixed equipment is a huge issue. MACOM and Midland are (were?) the only vendors making the traditional 110 watt continuous duty cabinet style equipment. Everybody else gave up.

Jim202 wrote:Your third problem is getting everyone to agree.


That's a problem. Not insurmountable, but still a problem.

Jim202 wrote:Your fifth problem is a radio shop that can still fix low band radios. Most of them have become radio swap out geeks.


Our local Moto people do a good job. Several surrounding counties still have active public safety users on 33, 37, and 39 MHz and business banders on 30, 31, 35, 47 and 48 MHz.

Jim202 wrote:Your sixth problem is still obtaining low band base antennas.


DB201. The Gold Standard in low band base antennas.

8)

W4WTF
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Postby W4WTF » Fri Jan 26, 2007 9:54 am

Potential downsides:

As you have noticed, fewer and fewer manufacturers support lowband. How long before nobody does? How long until your choice in equipment is one model?

Espeacially in portables.

Potential upsides...

HUGE amount of cheap used equipment for departments on a tight budget.

Personally, i would loo at VHF-HI.

w8cmi
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Postby w8cmi » Fri Jan 26, 2007 10:43 am

W4WTF wrote:Potential downsides: As you have noticed, fewer and fewer manufacturers support lowband. How long before nobody does? How long until your choice in equipment is one model?


As long as VHF low band is a licensable, working band of frequencies, I would think someone would provide equipment.

Espeacially in portables.


We're probably looking at UHF (or VHF High) portables working through a PAC-RT type system. The police cars, ambulances, and fire stations are too spread out in a hilly, rural area to put a reliable receiver infrastructure in place for low band portables. Besides, no one really makes a good low band portable, do they?

Potential upsides ... HUGE amount of cheap used equipment for departments on a tight budget.


The county will fund new equipment for public safety and government vehicles. The used surplus you speak of will probably be a big hit with the volunteer firefighters (for personal vehicles), the sheriff auxiliary, etc.

Personally, i would look at VHF-HI.


That's Plan B, and, to be honest, it has a lot more political support. Several key government agencies already use 151-159 MHz frequencies, and at least some of their equipment can simply be reprogrammed.

The other big selling point on VHF High is our small cities. The police, fire, and public works people are much more dependant on portable communication. There's more activity with city workers walking around (as opposed to driving), police bike patrols, meter readers, road construction where traffic needs to be flagged, etc. in town than in rural areas. It can be a technical mess to get PAC-RT repeaters to work properly when a six square mile sized town has three police cars on the road, and each PAC "cancels" the others out when they get within 1/4 mile of each other.

The existing VHF simplex and repeaters do an adequate job in these towns, but coverage is spotty when you get five or six miles away. As mentioned before, there are a few input/output issues to be dealt with, like a police repeater outputting on 159.1xx and the co-located fire repeater using 158.9xx as an input. Desense, anyone?

In any case, I really appreciate everyone's input. It helps me see pitfalls I may not have considered.

8)

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Postby wavetar » Fri Jan 26, 2007 12:57 pm

Perhaps a VHF-Hi repeater in the towns/cities, to allow for portable comms. Cross-band the VHF repeater to a low-band base to give low-band coverage outside of town. Have each vehicle set-up with both a VHF-Hi & low-band radio, with a controller set-up to allow cross banding between the two as the need dictates.

If you go out of VHF-Hi range outside of town, enable the cross band within a vehicle, and switch the VHF mobile & portables to a simplex "on scene" frequency. This allows for the use of the same VHF-Hi portables, and sends audio back to town on the low-band cross link.

Neighboring towns could have the same VHF-Hi on scene frequencies in their portables for local on scene interop, and would send their audio back to their town(s) on a different low-band frequency.

This is a simplified scenario, and things such as the need for multiple channels & what-not can quickly make for design headaches. Just some thoughts while I'm waiting for the work day to end.

Todd
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Grog
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Postby Grog » Fri Jan 26, 2007 1:25 pm

wavetar wrote:
This is a simplified scenario


Let me get dinner before you post the complex version, that'll take awhile to read :lol:

Why not Hi band for everyone? How many freqs are used right now (hi band)?

w8cmi
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Postby w8cmi » Fri Jan 26, 2007 2:52 pm

wavetar wrote:Perhaps a VHF-Hi repeater in the towns/cities, to allow for portable comms. Cross-band the VHF repeater to a low-band base to give low-band coverage outside of town.


I follow your logic. We had considered this ... even discussed it.

Have each vehicle set-up with both a VHF-Hi & low-band radio, with a controller set-up to allow cross banding between the two as the need dictates. If you go out of VHF-Hi range outside of town, enable the cross band within a vehicle, and switch the VHF mobile & portables to a simplex "on scene" frequency. This allows for the use of the same VHF-Hi portables, and sends audio back to town on the low-band cross link.


Not user friendly, unless you know something about radios. In my experience, trying to diagram this out for a class of county road workers, volunteer firefighters, or law enforcement officers can quickly turn into a nightmare.

All these folks want is push-to-talk and volume. In the case of public safety, this system must be infallable and must be capable of easy operation under highly stressful conditions. A cop chases the bad guy ten miles out of town and gets shot on the traffic stop, but can't get help because, while ducking bullets and then collapsing in his own blood, he forgot to switch from high band to low band so he could access the cross-link. No thanks.

Neighboring towns could have the same VHF-Hi on scene frequencies in their portables for local on scene interop, and would send their audio back to their town(s) on a different low-band frequency.


We studied re-use of frequencies in pairing some operations together on the same channel, and duplicating UHF PAC-RT frequencies where we could. All fire departments would use the same PAC channel. This would allow any firefighter from any department to access the dispatcher if any ONE piece of PAC-RT equipped fire equipment was on the scene. Law enforcement would be set up with different PAC frequencies for each agency, but also with a common tactical channel all agencies would have for special events, major police incidents, etc.

Thanks again for some great ideas. I really appreciate it!

8) Rick

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Postby wavetar » Fri Jan 26, 2007 3:11 pm

w8cmi wrote:Not user friendly, unless you know something about radios. In my experience, trying to diagram this out for a class of county road workers, volunteer firefighters, or law enforcement officers can quickly turn into a nightmare.

All these folks want is push-to-talk and volume. In the case of public safety, this system must be infallable and must be capable of easy operation under highly stressful conditions. A cop chases the bad guy ten miles out of town and gets shot on the traffic stop, but can't get help because, while ducking bullets and then collapsing in his own blood, he forgot to switch from high band to low band so he could access the cross-link. No thanks.


Point taken, and I agree the simplest route is usually the proper route. The challenge of making everyone let go of their VHF-Hi equipment might prove your biggest nightmare though.

w8cmi wrote:We studied re-use of frequencies in pairing some operations together on the same channel, and duplicating UHF PAC-RT frequencies where we could. All fire departments would use the same PAC channel. This would allow any firefighter from any department to access the dispatcher if any ONE piece of PAC-RT equipped fire equipment was on the scene. Law enforcement would be set up with different PAC frequencies for each agency, but also with a common tactical channel all agencies would have for special events, major police incidents, etc.


Fairly standard & field proven set-up, assuming you can get people to let go of VHF-Hi & roll with change. Good luck.

Todd
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Postby techie » Fri Jan 26, 2007 6:02 pm

wavetar wrote:Perhaps a VHF-Hi repeater in the towns/cities, to allow for portable comms. Cross-band the VHF repeater to a low-band base to give low-band coverage outside of town. Have each vehicle set-up with both a VHF-Hi & low-band radio, with a controller set-up to allow cross banding between the two as the need dictates.

If you go out of VHF-Hi range outside of town, enable the cross band within a vehicle, and switch the VHF mobile & portables to a simplex "on scene" frequency. This allows for the use of the same VHF-Hi portables, and sends audio back to town on the low-band cross link.

Neighboring towns could have the same VHF-Hi on scene frequencies in their portables for local on scene interop, and would send their audio back to their town(s) on a different low-band frequency.

This is a simplified scenario, and things such as the need for multiple channels & what-not can quickly make for design headaches. Just some thoughts while I'm waiting for the work day to end.

Todd


How about just having a loband radio with a hiband PAC-RT in the vehicle, plus the hiband repeater in the city, with loband and hiband repeaters linked fulltime.. Officers carry hiband portables.
When the officer gets far enough out that he needs the PAC-RT, he simply switches channels on the portable to access it.
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Postby Jim202 » Fri Jan 26, 2007 6:30 pm

One other comment that you should take into account.

There are a number of National Interoperability channels
available on the VHF (150) band. These can be used by
any public safety agency for mutual aid type communications.
They are not for daily communications. Most agencies
either don't know about these channels or don't use them
at all.

If nothing else, these channels can be used for just about
any incident and off load short range communications from
the normal channels. They can come in handy for traffic
control at accidents, fire ground comms between multiple
agencies and the like.

Check out the http://www.apcointl.org site and then do a search
for the "TAC STACK" white paper. It is not the save all
for interop coms, but will provide some channel info and
maybe some ideas.

Jim

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Postby w8cmi » Fri Jan 26, 2007 7:23 pm

Excellent ideas. Thank you.

8)

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Postby wavetar » Fri Jan 26, 2007 10:53 pm

techie wrote:
How about just having a loband radio with a hiband PAC-RT in the vehicle, plus the hiband repeater in the city, with loband and hiband repeaters linked fulltime.. Officers carry hiband portables.
When the officer gets far enough out that he needs the PAC-RT, he simply switches channels on the portable to access it.


Yeah, that's along the lines I was thinking, except far simpler & more idiot proof. I think we have a winner.

Todd
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Postby vcaruso » Sat Apr 14, 2007 10:46 am

W8CMI,

Has anything been done with your proposal?
We migrated to UHF about four years ago but never gave up our license on low band. The base stations were just sitting Idle until about two weeks ago when we had to travel up county and we found a dead spot in our UHF system. The good ol reliable low band saved the day, a few years back we acquired newer Kenwood mobiles with UHF PAC-RTs and Mastr III base stations from a nearby agency that was converting to T-band from low so we decided to replace the old Motorola gear in our trucks and keep low band as a back up.

We were toying around recently with going back to low band when we received a quote from Verizon for the RTNA circuits we need for three up county receivers to alleviate some of our coverage issues.....

Vertex, Kenwood, and M/A Com are still in the low band market so the niche is still there.

I'd like to hear how your proposal turned out

w8cmi
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Postby w8cmi » Sun Apr 15, 2007 10:03 am

It's on the shelf for now. There's a glitch in state funding for our wireless 9-1-1 conversion (a simultaneous project) and we had to divert about $57,000 to cover a necessary expense we hoped would be covered by a state grant. We've also changed EMA directors in the middle of the stream, and that's had an effect on overall planning.

There is still opposition, but several key leaders are warming to the idea. In a rural setting, there is simply no better bang for the buck than Low Band. And, with no reliance on repeaters or computers or trunking, you can't kill it when a disaster strikes.

Hey, it took almost 30 years to tear down the Berlin Wall.

I'll keep you posted. :wink:


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