Combining some mobile radios in the fire truck

[rrnewuser]

Hello,

We have two radios in our fire truck that we'd like to combine to just one ...

The first is a dash mounted mobile radio that does transmit/receive on 154-168 mhz.

The second is a portable radio that does transmit/receive on 462.xx mhz.

We'd like to just have one (dash mounted, mobile) device to cover these.

I *think* this is known as a "dual band" radio, however when I search for dual band radios I only seem to find radios that receive dual-band ... they are not transmitters at all. I need a radio that can receive and transmit on both of those bands (or has a big enough range that just covers them both anyway).

Any suggestions ?

 

[kayn1n32008]

Hello,



We have two radios in our fire truck that we'd like to combine to just one ...



The first is a dash mounted mobile radio that does transmit/receive on 154-168 mhz.



The second is a portable radio that does transmit/receive on 462.xx mhz.



We'd like to just have one (dash mounted, mobile) device to cover these.



I *think* this is known as a "dual band" radio, however when I search for dual band radios I only seem to find radios that receive dual-band ... they are not transmitters at all. I need a radio that can receive and transmit on both of those bands (or has a big enough range that just covers them both anyway).



Any suggestions ?

Kenwood makes the TK-x90 series of radios TK-790(VHF) and the TK-890(UHF) that can be linked to one control head to become a dual band radio. The downside is that it does not receive on both bands at the same time. With out having two separate radios, I know of no commercial radios that will receive two transmissions on different bands at the same time. Another couple of options are the Harris Unity mobile, or Motorola APX mobile. Again neither of these radios will receive on both bands at the same time. Nor will they transmit on both bands at the same time.


Sent from my iPad using Tapatalk

 

[n5ims]

While you can find dash mount dual band radios for your truck, they'll all be the top-of-the-line models and generally will cost more than having two separate radios. One other thing that may push you into the two radio solution is that when the radio is on one band, it's on that band so you'll miss calls on the other band, probably a deal-breaker for you. One other option is the dual-radio, single head design as indicated above. Same basic issue here though.

 

[mmckenna]

Two separate radios can be a cheaper and more reliable option in many cases. Being able to receive on both at the same time can be a real benefit. Relying on scan function to catch traffic can cause a lot of issues. While maybe not as elegant a solution, it might be better in this sort of service.

 

[rrnewuser]

Thanks for these helpful notes...

One of the two bands I mentioned is very seldom used and is a requirement just for edge cases... so the ability to receive on both bands is not a requirement.

So the consensus is that a single-deck solution does exist, but they are kind of oddball setups and there aren't a lot of choices - correct ?

One thing I wonder - why isn't there a single radio that just has a large enough band - from (roughly) 150-480 mhz - such that this isn't a weird "dual channel" radio ? Are these VHF and UHF bands so different that there isn't a common hardware that could do that whole range ?

(please correct, among other things, my terminology - I can use all the help I can get

 

[rfradioconsult]

Harris M7100 radios will do what you want, two radios one VHF one UHF, a single control head. This setup provides dual simultaneous receive, a very nice setup.

 

[FFPM571]

If the second radio is rarely used why spend the money on a dual band radio. Get a mobile in that band that you need and leave it at that.

 

[n5ims]

One of the two bands I mentioned is very seldom used and is a requirement just for edge cases... so the ability to receive on both bands is not a requirement.

So when you're out on one of the "edge cases" you're OK with no contact with your dispatch and other units in your department?

So the consensus is that a single-deck solution does exist, but they are kind of oddball setups and there aren't a lot of choices - correct ?

Correct. They're generally rare and expensive.

I really hate to mention this but one possible option is one of those cheap Chinese dual-band radios (like this Chinese Dual Band Mobile Radio). They'll be legal to use on your two frequency bands, but they're not built to the standards of most commercial radios you're accustom to. Frankly I wouldn't use them in any critical service although as a very light use, additional (and non-critical) coverage radio it may work OK. If you go that route, you may want to purchase several and keep spares for when (often it is when, not if) they fail, you'll have a replacement available.

One thing I wonder - why isn't there a single radio that just has a large enough band - from (roughly) 150-480 mhz - such that this isn't a weird "dual channel" radio ? Are these VHF and UHF bands so different that there isn't a common hardware that could do that whole range ?

This is mostly due to two main issues. First, the bands are much smaller than that and the license coverage will not allow you to transmit on most of the coverage of those radios so you'll be paying lots more for frequency coverage you can't use. Second, there are components that are optimized for performance on the bands a radio is designed for and if the radio must cover that wide of a range, you'll have serious issues in some areas and performance issues in most.

 

[USScanner]

Powerwerx Db-750 dual band mobile

http://www.powerwerx.com/two-way-radios/mobile-radios/db-750x-dual-band-commercial-mobile.html

 

[n5ims]

Powerwerx Db-750 dual band mobile

Powerwerx DB-750X Dual Band VHF/UHF 750 Channel Commercial Mobile Radio [DB-750X] - $299.99

Basically the same hardware as the AnyTone AT-5888UV I linked to above. Slightly different interface and firmware but the guts are pretty much the same. The caveats I gave about the "cheap Chinese radios" apply.

Review and comments on the Powerwerx are here http://forums.radioreference.com/bu...-uhf-750-channel-commercial-mobile-radio.html

 

[PACNWDude]

Very few dual receive radios.

The company I work for was using Yaesu FHT-2070/Vertex Duo handhelds for many years as they were true dual band radios. However, now it is very hard to find true dual band radios.

The posters who have said that having dedicated radios in individual bands have a point. They do tend to be more reliable.

Multi-band radios, when they fail, do tend to burn out one module, so a dual band radio may lose UHF only but still work on VHF. With software defined radios, firmware and programming may cause glitches and use may be buggy.

I carry a multi-band Harris Unity, that has been mostly reliable. I have had to power it down and power it back up when it was in 100 degree plus heat once.

As for dual band mobiles, Motorola APX series, Harris Unity or M7300/7100 may work for your needs.

 

[kayn1n32008]

One thing I wonder - why isn't there a single radio that just has a large enough band - from (roughly) 150-480 mhz - such that this isn't a weird "dual channel" radio ? Are these VHF and UHF bands so different that there isn't a common hardware that could do that whole range ?

Put simply, the radio has tuned circuits for receiving and transmitting. The components for 137-174MHz radio will not work for a 400-500MHz radio and even then the widest band split at UHF I have seen is 380-470MHz. While radios have covered more and more in one band split, physics is physics.

Plus there are a large part of the spectrum that LMR users are not allowed to operate. 174-380 are reserved for Television, Amateur radio and Military, except for a small segment around 220MHz used commercially.

From a manufacturer point of view, it makes zero sense to R&D a radio for portions of the spectrum that can not be used by LMR users.


Sent from my iPad using Tapatalk

 

[rrnewuser]

As for dual band mobiles, Motorola APX series, Harris Unity or M7300/7100 may work for your needs.

I'm confused by this - I looked up the PDF datasheets for both the M7300 and the 7100, and ... it appears there are three models - a p25, a vhf, and a uhf. I don't see a dual-band radio:

Harris PSPC

... same with the 7100 - I see a VHF datasheet, and although the page mentions UHF ... it's not there.

Sorry if I'm being dense - I took your post to mean that one of those two had a dual VHF/UHF model ?


Thanks.

 

[kayn1n32008]

Wirelessly posted (Mozilla/5.0 (BlackBerry; U; BlackBerry 9900; en-US) AppleWebKit/534.11+ (KHTML, like Gecko) Version/7.1.0.1047 Mobile Safari/534.11+)

P25 is. An option on the Harris radios. You can get a dual band set up, the dreawers are linked to one control head and they have to be programmed to work together.

 

[PACNWDude]

Harris Unity XG-100M mobile.

Has anyone used the Harris Unity XG-100M mobile?

If it works like my handheld "P" model, I have a mission plan setup with VHF and UHF and can scan and monitor both at the same time. May work for this firetruck, in the mobile "M" version.

The two radio setup on one control head could work as the previous poster said. This has been done with Motorola Spectra radios for a long time now.

I have not puts hands on one since IWCE a couple of years ago. The vendor was too busy shoving brochures into my bag as they saw the portable on my hip.

 

[mmckenna]

I've seen a few of the Unity mobiles, but never personally used one. Nice radio, but expensive. Any of these higher end dual or multi band mobiles will probably work just fine. The big hang up for most smaller departments is the cost. A $5000+ radio, vs. 2 $1000 mobiles is a big jump. If all you need is analog, it'd be a lot cheaper to go with separate radios. The increased flexibility, easier programming, and lower price is enough to make it worthwhile for many departments. I don't see where the control head space constraints would be an issue in the cab of an engine.

But, if you really want a single radio and cost is not an issue, there ya go.

 

[tech2461]

M7100/7300 dual band

Harris does not make what they call a dual band radio when it comes to the 7100/7300 series, per se.

What it amounts to is buying a radio chassis in each band and a special dual radio cable. It's more a dual radio than dual band, if you get my drift. Two RF decks to one control head. The Orion can do the same and depending on the cable, you can use a front mount radio and remote mount together as well with the front mount control head controlling both radios. The front mount radio must be wired as the master and the remote radio the slave. The radios must have the same firmware numbers flashed as well. You must also use a system type head and part of the kit allows you to recap some of the system head keys to allow you to switch which radio is master or slave. Each radio has its own speaker and the slave audio is always lower than the master on receive. The radio parameters are set individually. You can make a UHF slave the master and program it to scan a list of conventional channels, then swap it back to slave again and it will scan all the channels you selected with their audio at a lower level than the master. You have to manually swap back and forth between which radio is master and slave depending on which radio you wish to transmit on.

The XG100 is a true dual band radio and is seamless where the radio doesn't care what band each conventional channel is in. Channel 1 can be VHF, Channel 2 UHF and Channel 3 can be 800Mhz.

 

[ofd8001]

You might look at the Motorola APX line of radios. https://www.motorolasolutions.com/c...ment/static_files/apx7500_mobile_brochure.pdf

Yes, they will be pricey. I believe they will be a lot more rugged than the less costly models.

I spent 39 years in the fire service, 30 as a fire chief. Our work is brutal and equipment takes a beating. So it's best to spend the money up front rather than repeatedly later to replace equipment time and again.

The biggest challenge I've seen with two radios is that they both are active. One gets turned down so the other can be heard, but isn't turned back up later. So subsequent transmissions are missed.

 

[teufler]

original post was back in 2014. Think he has bought the necessary equipment by now.

 

[tech2461]

I'm sure he has... But I also thought it would be good for future reference to others.