LTR System : Need your suggestions.

Carl · Post by **Carl** » Tue Mar 27, 2007 10:37 am

Me and my partner want to setup a 4 channel UHF LTR repeater. Most probably for rental radio and some regular clients like towing, transport services, and construction. We want to use 4 MTR2000 for the repeater itself but we don't have any idea of wich controler to use and cavity/duplexer. For the mobile and portable we think to use ht1250ls, p1225ls, cdm1550ls+, m1225ls, and some kenwood. we already have microwave ethernet link and voip-ata to our shelter at the top of the hill so if the controler can be IP monitored or something like that it would be great because there is 4 feet of snow in the winter. Thanks.

Bat2way · Post by **Bat2way** » Wed Mar 28, 2007 11:49 am

connectsystems.com have a trunking controller. The cavity/duplexer thing is "how much do you WANT to spend"??? Lots of options from A-Z.

Seriously guys, if you're setting up a trunking system, and saying...

we don't have any idea of wich controler to use and cavity/duplexer

you really should find a technical partner who can handle this stuff locally for you. You'll get 10 different responses here and they may all make no sense.

fogster · Post by **fogster** » Wed Mar 28, 2007 2:59 pm

That has to be the worst website I have seen in a long time...

On-topic: Since I'm learning this myself: does any Motorola gear even do LTR? I was under the impression it didn't.

Post by **alex** » Wed Mar 28, 2007 3:19 pm

fogster wrote: does any Motorola gear even do LTR? I was under the impression it didn't.

Are you asking specificly about subsriber equipment or actual trunking / back end hardware?

-Alex

fogster · Post by **fogster** » Wed Mar 28, 2007 3:50 pm

Subscriber equipment (radios with no third-party mods).

Post by **escomm** » Wed Mar 28, 2007 4:25 pm

Of course Motorola has radios that will do LTR... current models include the CDM1550-LS+, HT1250-LS+, PR400, and PM400.

LTR is still hands down the most cost-effective trunking format for small to medium sized operations.

fogster · Post by **fogster** » Wed Mar 28, 2007 4:53 pm

escomm wrote:Of course Motorola has radios that will do LTR... current models include the CDM1550-LS+, HT1250-LS+, PR400, and PM400.

LTR is still hands down the most cost-effective trunking format for small to medium sized operations.

And yet higher-tier radios (e.g., anything ASTRO, etc.) won't do it?

Post by **escomm** » Wed Mar 28, 2007 5:02 pm

Why would they? LTR is not a high-tier trunking protocol. It's the same reason you don't see AES256 offered for the HT750...

LTR is basic, inexpensive, and it works.

Rayjk110 · Post by **Rayjk110** » Wed Mar 28, 2007 6:20 pm

escomm wrote:Why would they? LTR is not a high-tier trunking protocol. It's the same reason you don't see AES256 offered for the HT750...

LTR is basic, inexpensive, and it works.

Got that right. It's also the easiest to program, imo

Carl · Post by **Carl** » Wed Mar 28, 2007 10:09 pm

we are considering using LTR because it's inexpensive and i'm not stick with proprietary radio like the type2... but for a more dense area or higher traffic for sure we will use the motorola trunking system. again, it's money talk. I've already installed 2 of the CSI system a couple of years ago and it still works great, but the reason why i'm asking about suggestions it's because i know other manifacturer (like Zetron) can do it. so i wanna know which one is the prefered. for the filtration we ares considering using a Sinclair 4cavity set for each channel.

MSS-Dave · Post by **MSS-Dave** » Thu Mar 29, 2007 4:09 am

I've built several UHF LTR systems including 3 transportables. I used RKR 1225 (not by choice..) and MTR 2K with Trident Raider controllers. On all of the systems, I used DB Products DB4368 4 channel combiners. Now it's DB Spectra and Tessco doesn't even list them anymore. Closest thing would probably be EMR. You also need a receive multicoupler with a bandpass window filter. I don't know how licensing works in Canada on UHF or what your bandplan is but you need to try to get your channels in the same band and what I mean is in TX 450-455 RX 455-460 or TX 460-465 RX 465-470 (this is in the US..) with TX channel spacing at least 500 kHz apart to get max power out of your combiner. You have to have RX filtering and it will save you some $$$ if you only need 1 window filter as opposed to 2. Another important thing would be to do wideband (25 kHz channels) if it is available. It is somewhat more difficult to align narrowband and performance suffers more with weaker RX signals.

The Trident Raider panel worked well for me in these apps. I experimented with the CSI Flex 3 panels for another project and I found them somewhat more difficult to program but they do way more than the Raider will.

Whatever you do, DON'T cobble something together or cheap out, especially if you are going to rent time on the thing. Get the best equipment you can up front. Failures will kill your profits real quick...

Dave