London Unmarked Cars

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denseglow

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I was just recently took a trip to the capital, while there I saw some unmarked MET cars. However I notice none of them had radio antennas on them! Do the cops just use the portable radios for unmarked cars? To stay more covert or is it hidden secretly?

Thanks,
Bill
 

citylink_uk

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Hi,

All police operations are now on the nationwide TETRA system which offers 95% coverage from all roads in the UK from a 1W portable so mobile radios aren't really needed in covert cars.

Most patrol cars will have mobile's but I guess not having antennas on the unmarked cars makes them less conspicuous.
 

HillWalker

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Hi,

All police operations are now on the nationwide TETRA system which offers 95% coverage from all roads in the UK from a 1W portable so mobile radios aren't really needed in covert cars.

Most patrol cars will have mobile's but I guess not having antennas on the unmarked cars makes them less conspicuous.
As far as I'm aware, in Ireland at least, they're installing mobile Motorola TETRA units into both unmarked and marked cars. The Special Branch units have had them for years. But all the old marked and unmarked cars (pre-November 2009) still have VHF aerials visible. TETRA aerials are also visible, usually by a short, rubbery aerial on the rear quarter.
 

Raccon

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Hi,

All police operations are now on the nationwide TETRA system which offers 95% coverage from all roads in the UK from a 1W portable so mobile radios aren't really needed in covert cars.
Road coverage does not equal in-car coverage. To ensure proper reception for portables in the car and to ensure it can actually reach the base station when they need to transmit they would need at least some car kit with external antenna if no mobile is installed. Or drive with an open window at all times.
 

citylink_uk

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Road coverage does not equal in-car coverage. To ensure proper reception for portables in the car and to ensure it can actually reach the base station when they need to transmit they would need at least some car kit with external antenna if no mobile is installed. Or drive with an open window at all times.
What I actually should have said is 95% coverage from a mobile radio on all mettled roads. The network was designed for portables from the outset and given that even mobiles only output 3 Watts on average (not counting cable loss), I expect most of the coverage area would indeed enable in vehicle handheld operation without any external antenna.
 

Raccon

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What I actually should have said is 95% coverage from a mobile radio on all mettled roads. The network was designed for portables from the outset and given that even mobiles only output 3 Watts on average (not counting cable loss), I expect most of the coverage area would indeed enable in vehicle handheld operation without any external antenna.
Typical in-car loss is about 8-10dB, compared to around 3dB body loss. That difference can have a big impact on the coverage (up- and downlink).
 

fmoo7

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Tetra radios and antennas

I recently witnessed a covert car in Brixton which appeared to employ some sort of am/fm disquise aerial, has anyone else come across this?
 

citylink_uk

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They use all sorts, mainly just a 1/4 wave whip as it doesn't really stand out at UHF.

This seems to be one of the most popular antennas for Airwave and seems to be used on all Fire Service and NHS rollouts. It combines a UHF whip with GPS antenna.


I haven't seen many 'covert' antennas for TETRA on vehicles, mainly just the 1/4 wave.
 

n5ims

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Antennas on unmarked cars aren't always where you'd put them on normal marked units. They may be mounted in wierd locations as well as pointing in wierd directions. I've seen them mounted places such as behind the bumpers, in the engine compartment, as well as in the wheel wells. It's pretty easy to mount a 3" - 6" antenna where it will still work (not as well as center of the roof of course) and not be easily visible to the general public.
 

code3cowboy

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You can either hide a "regular" antenna or use a covert antenna, or one designed to not be seen.
 

phillmobile

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just to help you yanks out we call cellphones mobiles and cell towers are called masts for some reason.

then again for some reason anything to do with a antenna system seems to be called a mast, just thick public i guess really gets up my nose.

then again the call bowling pins skittles duh

whos ever heard of ten skittle bowling
 

gewecke

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just to help you yanks out we call cellphones mobiles and cell towers are called masts for some reason.

then again for some reason anything to do with a antenna system seems to be called a mast, just thick public i guess really gets up my nose.

then again the call bowling pins skittles duh

whos ever heard of ten skittle bowling
When I was over the pond, they called women "byrds" :)
I know, I know a bit off topic....

73,
n9zas
 

sepura

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Patient Reports?

Do hospitals in England have TETRA radios at the hospital to recieve patient reports while the ambo is enroute to hospital or not? This is how they do it in the USA. Also, I am making a trip to England soon! Does any of the public safety still have analog radios in their vehicles? Or have they throw them all out? lol


Thanks.
 
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