XPR 4300 question

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brin831
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XPR 4300 question

Post by brin831 »

looking for some information on MOTOTRBO XPR 4300 mobile ...

anyone tried to set up a repeater with two mobiles? in analogue or digital for that matter? if i'm not mistaken the accy connector isn't disabled in digital like on the 8300 repeater ...

and speaking of the 8300 repeater it is basically two mobiles and its rated for 100% continuous duty so then could one conclude that a mobile could be used in the same manner given simply a cooling fan perhaps ...

my question comes because we currently use a couple cdm radios for a constant tx application but have a 8300 repeater and a few other digital radios but they are also used in analogue ... do you see an advantage between the xpr 4300 over say a cdm series radio besides the obvious digital capability?

we are slowly moving in the digital direction but not for a few more years so with that said should i purchase a couple more cdm's or go with the xpr mobiles instead with the hopes of going digital someday?!?
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d119
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Re: XPR 4300 question

Post by d119 »

Keep in mind the repeater has considerably more heatsink attached to the transmit radio besides the cooling fan.
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wavetar
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Re: XPR 4300 question

Post by wavetar »

d119 wrote:Keep in mind the repeater has considerably more heatsink attached to the transmit radio besides the cooling fan.
And not only that, but despite what Motorola claims, cannot maintain 100% duty cycle at full rated power. We've had both our UHF & VHF demo unit transmitters fail, as well as two customer units, again one in UHF & one in VHF. None of these units had anywhere close to 100% duty...I'd be surprised if any of them even approached 50% in any given hour at any point. We're to the point of setting all repeaters sold to about 70% of rated power...basically the same thing we always had to do for the GR1225 series stuff.

To brin831, making a repeater out of the XPR mobiles in analog is easy enough, as you are correct that the accessory connectors are 'live'. They are also 'live' in digital mode, but do not provide a COR output...at least they hadn't in the past, I haven't checked with the last several firmware upgrades whether that's been rectified or not. If not, you can check out a circuit I built (at the suggestion of another board member, "Astro Spectra") in the following thread:

http://batboard.batlabs.com/viewtopic.p ... +crossband

Ignore where it says 'NTE291' in the pic...it was something I overlooked erasing. It's been working reliably for us for several years now.
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brin831
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Re: XPR 4300 question

Post by brin831 »

well we are only licensed to 10 watts so what we are talking about is much much less than total power ... less than 25% ...

we currently have used a couple cdm 750 radio's in this capacity for a while, we use them to setup a com system through a couple hand held radios and a telex wired system

they have been fine need to keep the air moving over them but they stay fairly cool ... and we are talking about probably 6 hr a day operation couple days a week in an remote production type setup.

i would really like to move in the digital direction ... but concerned about the reliability of the newer mobile units ...

one other completely different question ?? maybe this should be a different topic>> but ...

we really only have space for one antenna but need to run 2 tx and 2 rx off of it ... basically need to combine 2 duplexers from repeaters ...
can this be done and this is what i was looking at http://www.e-meca.com/rf-power-divider/ ... specsID=23

thanks for all the help i have learned so much just by reading this board over the last few months !
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wavetar
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Re: XPR 4300 question

Post by wavetar »

For what it's worth, I don't recall any transmitter failures with the XPR mobiles...with regular mobile use at least. FYI, if you want 10 watts, you must get the lower powered 1-25 watt units. The 'standard' higher powered units don't go below 20 watts. So, you'll be running at close to 50% rated power.
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