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Any DVRS recommendations?

Posted: Wed Jan 23, 2013 9:24 am
by jmac4936
We are looking for a vehicle mounted repeater that can be removed and put in another vehicle on a regular basis. We are using XTS5000 portables UHF/VHF for comm's between 3 trucks spread out up to 1+miles over various terrain, mountains, flat, urban, etc.... One of our problems is our trucks are heavily armored and the lead truck can hear the trail trucks transmission without a problem, but not vice versa, unless we are within say, 2-300 meters. I think this has to do with the radio signals basically being deflected forward by the armor. So we were thinking that a DVRS with an external antenna mounted on the side of the middle truck would enhance comm's between all three trucks. We are not radio guys and would need something pretty idiot proof, plug in play kinda thing. Are there any suggestions?? BTW, this is coming out of pocket so money IS def a limiting factor, ie; a 10-12k MOBEXCOM P25 is def out of the question...
Thanks,
John

Re: Any DVRS recommendations?

Posted: Wed Jan 23, 2013 2:41 pm
by wavetar
It would be a whole lot cheaper to simply install roof-mount antennas on your trucks and run the leads into the cab. Connect a portable to the antenna while in the truck with an SMA adapter and you'll talk for miles & miles.

Re: Any DVRS recommendations?

Posted: Wed Jan 23, 2013 6:08 pm
by thebigphish
mobile radios are out....why?

Re: Any DVRS recommendations?

Posted: Wed Jan 23, 2013 6:35 pm
by mikegilbert
Pick up a few Motorola XTVAs with power amps. That'll run maybe a grand for a couple of them. Your radios will act like mobiles and will be charging all the time. Seems like a win-win.

thebigphish wrote:mobile radios are out....why?


He's referring to the MobexCom DVRS- not mobile radios.

Re: Any DVRS recommendations?

Posted: Thu Jan 24, 2013 11:51 am
by thebigphish
Sorry, I had formatted my question poorly. I'm just a little suprised that a group that has "heavily armored vehicles" would be stuck using out of pocket money to fix communications issues. Why has't installations of mobile radios in the vehicles been considered? the handful of watts coming out of a rubber duck antenna inside a rolling faraday cage is a pittance compared to a mobile radio with a quarterwave on the roof...

Re: Any DVRS recommendations?

Posted: Fri Jan 25, 2013 1:56 am
by jmac4936
I don't really have an answer for you phish...other than it being office bean counter mentality versus in the field worker. I did like the suggestion by wavetar of plugging a roof mounted antenna into the portable but ran into the problem of having to rapidly dismount the trucks so in my research I came up with an idea but I'm not sure if it will work. I sent him/her a PM but haven't received a reply...maybe one of you guys can chime in.
My dilemma is this; we have the radios attached to our vests generally out the way and it is cumbersome to do anything but change channels/volume and they are wired with an extended antenna secured to the Molle straps. If we have to dismount in an emergent situation we don't have time to unscrew the roof mount and screw the extended antenna back in, which would be next to impossible to do anyway with the way we have them attached. I saw that the XTS5000 series uses an RF adapter for the public safety mic which led me to another thread here. The guy was asking what adapter to use for a roof mount and the replies said an SMA to BNC. I looked up the adapters and saw that they have Tee connectors. I am mechanically inclined, but lack the electrical engineering to know if this will work. My idea is this...use a Male SMA - whatever style connector for roof mount antenna - Female SMA Tee style connector to:
1) Male SMA to plug into the radio, 2) whatever style connector for roof mount antenna to plug a short pig tail with a male phono type jack which then plugs into a female phono type jack and continues out to the roof mount antenna (this would serve as a quick disconnect from the roof mount antenna), 3) Female SMA to plug the extended antenna into. This would serve two purposes, it would allow us to keep the extended antenna plugged in AND give us the roof mount antenna we need with a quick disconnect when we dismount.
My questions are this:
Is it possible to have both antennas attached at the same time?

And if so, we are setting up the radios to operate both UHF/VHF freq's by switching from the "A" bank to "C" bank. Will the connectors and roof mount antenna support both types of bands?

I'm not sure of the connector type for the roof mount antenna or even which type of roof mount antenna I need, can you tell me what you think would be best?

If the pigtail idea will work the connector can be considered permanently attached. If not, I would need some kind of terminating quick disconnect to plug into the Tee connector.

Regarding the roof mount antenna itself, can you suggest a vendor that would be able to supply an antenna with the wire as I described with the phono type jacks and pigtail with the connector?
Regards,
John

Re: Any DVRS recommendations?

Posted: Wed Jan 30, 2013 11:46 am
by SlimBob
You're going to have to have an antenna wire run in the armored vehicle to get outside for the repeater. Or put the repeater in a non-armored vehicle.