small uhf repeater

Post by **harrisjt2000** » Thu May 06, 2004 4:31 pm

here in town the county has moved to 800mhz in 2001 and kept the uhf towers up and running and now they took them out of service and the sheriffs office law enforcement explorer group was on the uhf system they have tried to use there radios as simplex but thats not working for them so i was thinking since the county still has there uhf licence for four more years that i could make a small type repeater and was wondering what i need to do to get this working

W4WTF · Post by **W4WTF** » Thu May 06, 2004 5:26 pm

Well at a minimum 2 maxtrac/radius portables, a duplxer, and either a rick or one of the homebrew interfaces foundon the batlabs pages.

If your lucky the duplexer may still be around in the counties hands.

Post by **harrisjt2000** » Thu May 06, 2004 5:36 pm

do i need a duplexer cant i just use a rick

Post by **harrisjt2000** » Thu May 06, 2004 5:40 pm

and two antannas

W4WTF · Post by **W4WTF** » Thu May 06, 2004 5:43 pm

Nope. The rick interfaces the radios, the duplexer goes inline with the antenna to seperate the transmit/recive signals and send them to the proper radio of the pair.

That said, if you are this new to it you need to find someone more experienced to set things up for you. Your best bet will probably be getting a used Desktrac and having your local shop set it up.

Post by **harrisjt2000** » Thu May 06, 2004 5:47 pm

do you have to have a duplexer or can you just have two antennas also this is going into a van

RKG · Post by **RKG** » Thu May 06, 2004 6:23 pm

Not to throw cold water, but you should take a close look at that license with four more years on it and satisfy yourself that the application (for police use) and frequency (likely limited to police use) includes use for an LE explorer function. If not, the license would not authorize transmissions on the frequency.

kcbooboo · Post by **kcbooboo** » Fri May 07, 2004 5:20 am

You can use two antennas provided they're separated vertically on a tower sufficient to keep the transmitted signal out of the receiver. On a van, you probably won't have any vertical separation, as you'd likely mount two antennas on the roof. This would give you the least amount of attenuation, and would almost guarantee poor performance. In this situation a duplexer and only one antenna would be far, far superior, and highly recommended. Mobile duplexers are small and inexpensive and should be sufficient for your application.

The R.I.C.K. unit is used to connect the two radios together so the receive audio makes it to the transmitter, and the transmitter is keyed up when a signal is received. This product may perform other interface duties as well. You'll probably need a way to make the repeater identify itself periodically, depending on the license requirements. I don't think this is done by the R.I.C.K. unit.

Bob M.

N4DES · Post by **N4DES** » Fri May 07, 2004 9:17 am

RKG wrote:Not to throw cold water, but you should take a close look at that license with four more years on it and satisfy yourself that the application (for police use) and frequency (likely limited to police use) includes use for an LE explorer function. If not, the license would not authorize transmissions on the frequency.

In addition to that, if they moved to a 821/866 NPSPAC system there is also a requirement for the licensee to return (or let expire) the current conventional licenses to the FCC. They can't renew the licenses once they expire as this is written into the Region 9 NPSPAC plan for the SOF that there has to be a relinquishment plan approved by the Region Committee.

Now this is only valid with NPSPAC frequencies. If they use the lower 806/851 channels then what I said before doesn't apply and the UHF frequencies can be renewed as they see fit.

Post by **harrisjt2000** » Fri May 07, 2004 10:12 am

would these duplexers be good to use
http://www.universal-radio.com/catalog/ ... uplex.html

W4WTF · Post by **W4WTF** » Fri May 07, 2004 10:32 am

Nope, thsoe are diplexers, not duplexers despite what they are calling them.

You really need to get someone more familiar with repeaters and radios in general to assit you locally with this.

nmfire10 · Post by **nmfire10** » Fri May 07, 2004 11:37 am

Can you just use simplex?? I mean, a repeater with an antenna at ground level talking to portable radios is not going to get you very far. If you are just operating in one area, re-program the radios for simplex and just talk direct from radio to radio.

Doug · Post by **Doug** » Fri May 07, 2004 1:48 pm

I hate to ran on your parade but...your not going to be satisfied with the setup. I'm involved with a local Red Cross chapter and we use something very similar to what you mention except we can get our antenna up in the range of about 45 feet. With the antenna that high and going through losses of mobil duplxers and feed line we generaly get a good reliable(key word) range of about 5 miles or so from the portable repeater site with our HT's which happens to be the range we were looking for. Your mileage may very depending on your terrain.
Doug

Post by **harrisjt2000** » Fri May 07, 2004 4:31 pm

weve tried simplex its not working for them we were talking to the 800mhz system admin and he said he could get us on the system with are own talkgroup but we would have to supply are own radios i was wondering its is a type IIi smartne system could i use type I and II smartnet and privacy plus radios on this system becase i have about 70 stx type II and I and a couple mtx PP

nmfire10 · Post by **nmfire10** » Fri May 07, 2004 5:44 pm

harrisjt2000 wrote:weve tried simplex its not working for them we were talking to the 800mhz system admin and he said he could get us on the system with are own talkgroup but we would have to supply are own radios i was wondering its is a type IIi smartne system could i use type I and II smartnet and privacy plus radios on this system becase i have about 70 stx type II and I and a couple mtx PP

Ok. But you van is still at ground level. It is not going hear your portable radios any better than someone with a portable standing next to the van. If it can't hear it, it isn't going to repeat it. On top of that, it won't transmit a whole lot further than a portable standing there. The increaded TX power still has a limited range due to being on the ground.

RadioSouth · Post by **RadioSouth** » Fri May 07, 2004 6:33 pm

harrisjt2000 wrote:here in town the county has moved to 800mhz in 2001 and kept the uhf towers up and running and now they took them out of service and the sheriffs office law enforcement explorer group was on the uhf system they have tried to use there radios as simplex but thats not working for them so i was thinking since the county still has there uhf licence for four more years that i could make a small type repeater and was wondering what i need to do to get this working

Which town might this be ??

small uhf repeater

small uhf repeater

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Re: small uhf repeater