GMRS Repeater

[quarterwave]

I have a 35-watt mobile. Many GMRS operators with mobiles (not portables) are using similar power levels. Of what possible use is a 5- or 10-watt repeater? If you put it on top of a tall enough mountain, then it will only be usable as far away as the base of said mountain.

I read all through this post before realizing it was like 3 years old....oh well.

Yeah, years ago when I managed for M we had a customer, this lady in a rural area, she was a mushroom farmer and a realtor. She had an HT600 portable at her office, one for her farm hand, a 100 Watt Syntor mobile in her Bronco, and a 25 Watt R100 Repeater with interconnect on the tallest tower in 3 county's, I think her antenna (ASP 10 dB fiberglass) was at 450 feet, and she had 7/8" hardline on it. (Obviously a M sales genius sold this one....lol). Anyway, the Techs were getting calls on it after a while. She was using the interconnect all the time, over heating the repeater and her mobile. The lead tech turned her mobile down to about 20 watts, and then worked on her repeater he cut it to about 10 watts, put a blower (not a fan!) on it, and piped some A/C from the site HVAC over to the repeater case and plumbed it right in...so it had like 50 degree air blowing in the cabinet in the summer, and the blower on the heatsink all the time. He said she got about 2 watts out of the antenna. She had all kinds of coverage...it was amazing. That deal worked for several years until AT&T built AMPS Cellular there and she bought a phone. Nightmarish all the crap I remember.

 

[Shawnlin20]

Three years later and I'm still looking. There has got to be a place that has or can build a portable 5-10 watt all in one repeater. And for you morons that need a breakdown. Portable = one case with dup, power supply and repeater all enclosed. I want to plug it in and repeat. For use mobile or desktop. Thanks to everyone for going off topic so many times and questioning the use of such a low power.

 

[kayn1n32008]

Wirelessly posted (Mozilla/5.0 (BlackBerry; U; BlackBerry 9780; en-US) AppleWebKit/534.8+ (KHTML, like Gecko) Version/6.0.0.600 Mobile Safari/534.8+)

Three years later and I'm still looking. There has got to be a place that has or can build a portable 5-10 watt all in one repeater. And for you morons that need a breakdown. Portable = one case with dup, power supply and repeater all enclosed. I want to plug it in and repeat. For use mobile or desktop. Thanks to everyone for going off topic so many times and questioning the use of such a low power.

Calling people morons is NOT the way to get help. And for the record, I support the idea of a low power repeater. Beyond that good luck!

 

[robertmac]

Are repeaters on GMRS legal in Canada? I thought FRS/GMRS was limited to 2 watts output. Just to make sure Canadian readers of this forum understand it is different.

 

[kayn1n32008]

Wirelessly posted (Mozilla/5.0 (BlackBerry; U; BlackBerry 9780; en-US) AppleWebKit/534.8+ (KHTML, like Gecko) Version/6.0.0.600 Mobile Safari/534.8+)

Are repeaters on GMRS legal in Canada? I thought FRS/GMRS was limited to 2 watts output. Just to make sure Canadian readers of this forum understand it is different.

No, repeaters are not allowed in Canada. Yes, FRS/GMRS is limited to 2watts, and must have fixed antennas.

 

[quarterwave]

I really don't think it is that hard to find a repeater. 3 years?

Buy a Bridgecom and put it in a short, travel case 19" A/V type rack.

 

[jeepsandradios]

Motorola, ICOM, Kenwood and just about every other manufacturer makes a low power all in one repeater. Just plug in and hook up antenna. The most common is the GR1225 desktop repeater.

 

[k8zgw]

LOW POWER REPEATER

I AM REALLY SURPRISED THAT NO ONE SUGGESTED RITRON !

Ritron 5 Watts Liberty Repeater, not cheap, but works well.

Cost about $1000-1100.plus antenna.

I had one installed in a chemical plant, with a 3 Db antenna,
mounted upside-down in the elevator penthouse.
Been in and working for almost 10 years, there is no place
on the property you can hide from the repeater.

There are a lot of uses for a low power repeater,
I had an older Ritron 5 watt repeater, with a 3 db mag mount
magnet-ed to a vent duct "upside down" and it was usable for
better then a 5 mile radius, ( it was on the 13th floor.)


Don

 

[Project25_MASTR]

A friend of mine had a GR300 (all in one) sitting at the base of his 100 ft tower with a DB420 on it…blown PA was putting out 2W out of the radio…it was talking for 10 miles or more.

We put another friend's mobile repeater 80 ft up on his tower…12W out of the cans and will talk with an HT for 10+ miles. He uses it in his truck when he goes elk hunting in Colorado. It's a repeater based off a GR300 using a wooden box and SM50 radios.

I have a portable repeater that runs 12W out of the cans using Icom F420S radios. It's only setup to cover 10 miles or so (for hunting purposes or emergency deployment) and setup to run completely on solar power but I've been tweaking some stuff on it and have everything out of the box for individual testing. Even thinking about throwing an IF amp in it to give it a little better ears. Put it on a DB420 and it will talk for 20 miles easily. The antenna that stays with it is the top two elements of a DB420 (only has about 2 dB of gain).

The reason to build lower power repeaters is simple. Most mobiles aren't made to run 40% duty at full power…your lucky to get 15% duty at full power. Also, a good antenna can turn a cheap radio into an expensive radio. That said, in my area we have two main GMRS repeaters, one is on the tallest building for 120 miles and runs 50W out of the duplexer (its a SM50/Maratrac concoction). You can talk to it 40 miles away (depending on relative position). The other 100 ft lower in elevation, 2 blocks away running 25W out of the duplexer (GR500). It talks just as far, just doesn't have the receive.

A low power repeater is not that hard to get into. Something from say an Icom F300 or F100 series just needs a cable that can be bought from Preston-Moore and some programming to act as a repeater. Motorola 16 pin radios (Maxtrac, GM300, SM50/120, M1225) need a little cable that can be bought from China for $15 and some minor programming. I'm sure Kenwood and VS have similar options. Duplexers from China can be purchased for under $100 tuned and I haven't heard anything bad about them when compared to Celwave duplexers. I've got $50 into my portable repeater (minus the solar provisions).

This is a video of the SM50 repeater and my bastardized DB420 when we set it up at field day. I got 8 miles out of it, testing it off an HT in my dd, no external antennas.
Portable Repeater

 

[k8zgw]

This just proves it

For all the "nah sayers", there is a lot of uses for low power repeaters.

 

[Logan005]

I agree, my repeater is old, only 25 watt's and only 30 feet high, and I can hit it from my hand set from up to 10 miles here in Florida. Of course, "I want more" but this inexpensive setup could serve many of purposes that does not require you to stomp all over the frequency and other users. I would like to have the ability to adjust the power out, so as to do some propagation checks at lower power. Antenna height and excellent feedline is a must. LMR400 is a minimum for feedline and a well tuned duplexer. I plan to mount my repeater in an environmental enclosure on the side of the tower to further reduce the length of the feedline. but I bet if I reduced my output power by half and raised my antenna another 10 feet, I would have as good or better propagation. so yes a I believe you are correct, every application is different, most people just go with higher power needlessly.

 

[mformby]

Portable/mobile repeater

I would like to purchase a 5-10watt GMRS repeater. I have seen several repeaters that people have built out of mobile or handheld radios but I am not a master with electronics. I would need a plug and repeater type. As in receiver, transmitter, duplexer, controler, and power supply all in one box. If someone could build one or let me know where to purchase one I would appreciate it. Also, a mobile version of this would be great too. One to use in my truck. Thanks in advance.

S

You might look around on the WWW for a Motorola GR300 repeater. They are out of production but they probably can be found. It was a metal housing with 2 mobiles, duplexer, ad/dc power supply and a RIC (repeater interface controller). It can be wired with a cigarette lighter plug for mobile use with a mag mount antenna. As a retired Motorola dealer of 25 years I sold lots of them. They work great and are very compact but durable.

 

[mformby]

5 Watt repeater?

Having a 5 watt repeater defeats the purpose of having a repeater (in my opinion).

GMRSOutlet.com has some repeaters built from mobiles as well as real repeaters and they have all the parts as well.

I can think of several applications where this would work, but will only give one. A rather large Walmart Distribution Center had a fire wall right down the middle of it which blocked the 4 watt portables from getting through on occasion. A 5 watt repeater mounted on the wall with an antenna on each side of the wall solved the problem.

 

[Project25_MASTR]

You might look around on the WWW for a Motorola GR300 repeater. They are out of production but they probably can be found. It was a metal housing with 2 mobiles, duplexer, ad/dc power supply and a RIC (repeater interface controller). It can be wired with a cigarette lighter plug for mobile use with a mag mount antenna. As a retired Motorola dealer of 25 years I sold lots of them. They work great and are very compact but durable.

I've dealt with one GR300 and one GR500. The RIC is stupid simple as far as plug-n-play goes, but you can obtain the same thing with a $15 chinese made cable through the programming. A small wooden box/ammo box would probably work just as well. I'm finding the GR repeaters are a little more difficult to find because unlike the specific systems, all one has to do to Narrowband them is really replace the TX radio with a narrowbanded model.