looking for FULL duplex UHF mobile any info?

[wazzzzzzzzup]

im setting up a 444Mhz HAM GR400 repeater with a ZR340 phone interconnect controller at my home on a tower, im interested in mounting some kind of full duplex mobile in my car that i could use as a Phone thru the repeater

ive searched the forum, found references to the 800/900 privacy plus 1000, others talking about full duplex repeaters. but not exactly what im looking for.
im aware of maxtracs/spectras ect.. that use handsets but those arent full duplex to my knowledge.

the PP1000 is pretty much what im looking for, only in UHF band not 800/900 (i know the pp1000 was only made in 800/900)



wazz

[Bill_G]

Seventh word in - you answered your own question.

[wazzzzzzzzup]

Seventh word in - you answered your own question.

could you be more specific..... 7th word is (if counting the a) GR400, the repeater.
im asking about a full duplex radio to be used in my car.

[Bill_G]

Your count is correct. A GR400 repeater is a full duplex radio. You could try to find a GR1225 which is probably the only modern full duplex single chassis radio available. The need no longer exists. Cellphones took that job. So, not much land mobile product out there. Your alternative is to marry up two mobiles with a duplexer.

[wazzzzzzzzup]

thank you for the info.

it just happens that i have a GR1225 in the mail to me, i was going to part it out, but now i will take a closer look at keeping the radio section for a car project

[Bill_G]

A GR1225 will be a bit clunky because of the size. The control panel uses ribbon cables, and there generally isn't a speaker included. So, you'll end up keeping the large housing to hold the radio, the front panel, the duplexer, and possibly getting a speaker in there someplace somehow some way. Because of it's size, you couldn't install it anything smaller then a Suburban. Possibly a KW. Certainly not a VW. And then there's the whole matter of getting the thing programmed to not act like a repeater (which might be impossible).

It would almost be better to use something like the GR400 double mobile stack with the built in duplexer so you could (A) receive through a front panel speaker (novel concept) on the receiver radio, and (B) transmit on demand with a mic ptt button that is conveniently plugged into the transmit radio. Still kinda large, but easier to deal with. And the programming is much simpler since you can pull the repeater cables out of the back to stop that whole repeater repeating stuff from happening, but still keeping the full duplex.

Way mondo betterer.

[Astro Spectra]

Is cross band an option?

[Bill_G]

Is cross band an option?

Sure, but what benefit would it offer? A way to not require a duplexer? Maybe, but it would require a second hole in the roof, some distance between the antennas, and it would require the base repeater be crossbanded as well. Now it will also have two antennas, and two lines. Sticking with basic GR repeaters would be a lot simpler, and better performing.

[Astro Spectra]

I use a high pass / low pass diplexer in my 3 series BMW where antenna space is at a premium to run a XTL2500 dual band set up with a single antenna fitted on the roof where the cellular antenna normally fits. Works for me.

The problem with a duplexer and single band duplex mobile is you are limited to a very narrow range of frequencies with a band-pass / band-reject and other small mobile duplexers unless you can engineer a 10 MHz or better split at UHF. While not an issue perhaps if cellular replacement is the only application, it's a limitation if other frequencies are required.

Since the OP said it was a ham application, cross band would enable a wider choice of dual mobiles rather than as you pointed out the duplex capable '1225.

[Bill_G]

Now that's clever.

Merry Christmas.

[MassFD]

I know they are old and rock bound (channel elements) but the Mitrek is real easy to duplex, they are 25khz only but in the ham band it does not matter.

cut 1 wire add a jumper and a duplexer and you have a full duplex radio with audio better than any late model radio I have heard.

If you only need a single freq it may work out for you, they are almost free since narrowbanding.

[Bill_G]

You can duplex a Maxtrac too. Requires a little surgery, and a duplexer, but it's not impossible.