Vehicular Repeater = Mobile Extender?

[Dave_D]

Hi all,

Just curious. Is a "vehicular repeater" the same thing as a "mobile extender?"

I was thinking that a vehicular repeater extended a radio system's coverage area by several miles, by bouncing signals off of certain cars. But everything I'm reading seems to indicate otherwise.

Thank you!

Dave

 

[hill]

Yes, you are right.

 

[kb2vxa]

Yup, it's actually a cross band repeater in a vehicle. "Mobile extender" is a bit misleading, a better name would be portable extender because it repeats the signal from a portable and not another mobile. They call it a mobile extender/repeater only because it's mobile, oh well.

 

[MFD4305]

A Small Addition

Dave,
A vehicular repeater or mobile extender is a means of boosting a portable radio's signal, usually 5 watts or so, to the apparatus' (patrol car, fire engine, etc) output level which may be 30, 50, or occasionally 100 watts. The result is to increase significantly the range of the portable, often contributing to a P.O. or F.F.'s safety and effectiveness.

5 watt portable -----> 50 watt mobile -----> base and/or other mobiles

 

[N9JIG]

Mobile Extenders and Vehicular Repeaters are basically the same thing. Some are "Cross-Band" (meaning that the portable and mobile radios are on different bands) and some are "In-Band" (Both are on the same band).

In-Band units often use freqs as far separated from the mobile as the portable will allow. In-Band units also allow the portable to use either the Extender or the main channel directly, whichever works best at the moment. This also allows agencies to save money since they already usually have portables on that band and they also do not have to have an extra radio to use the extender.

In my area the 700/800 MHz. StarCom21 system has both in-band extenders (ISP units) and Cross-Band units (some local agencies in McLean County) in operation. The ISP's old 42 MHz. Low Band system used to use 155.505 cross-band extenders.

Many Extender systems also allow users to talk directly to each other without activating the extender by disabling the PL. With the PL transmitted the extender activates and sends the audio thru the mobile radio. With no PL the extender ignores the traffic and only local units on the extender channel would hear it. This is very handy for at-scene communications.

Some extenders use DTMF tones to change channels or turn it on and off.

To sort of counter Warren, "Mobile Extender" is a preferred title in some areas as they "extend" the use of the mobile radio to units away from the car. I guess it is all semantics...

 

[Dave_D]

Thank you, everyone!!!

Dave

 

[chrismol1]

When I was new to vehicular repeaters I looked up a lot about their controls and specs and everything. The repeaters are only good for a few miles at maximum conditions. There output power is about
100mW to about 500mW, and some can be tuned to 1 watt I think, but there only good for just as they are, for the officers to get out of there car and communicated around a 50 foot area maybe or a short foot chase. Would probably be worthwhile to make it as a regular repeater but you need 2 different bands or radios and not to forget the receiver radio and the other transmitter for it.

 

[danielkarluk]

how would i find out what frequency that the portables are transmitting on?