Another thread seeking GMRS repeater help.

[aaronK]

Okay so I'm looking to build a GMRS repeater setup to be used in conjunction with Motorola MR355R HTs.
From reading posts here I've come up with Radio-Tone Duplex repeater controller - Radioshop888 KG-UVD1P KG-UV6D TG-UV2 ROIP Repeater Controller Speaker Mic Ham Radio KG-669 KG-689 PX-777 PX-888 FT-897 FT-857 VX-177 VXA-300 KG-679 VEV-3288S V-1000 TG-UV FT-817ND FT-60R FT-897 FT-857 VX-7R VX- and 50W UHF 6 Cavity Duplexer ( N ) for Radio Repeater - Radioshop888 KG-UVD1P KG-UV6D TG-UV2 ROIP Repeater Controller Speaker Mic Ham Radio KG-669 KG-689 PX-777 PX-888 FT-897 FT-857 VX-177 VXA-300 KG-679 VEV-3288S V-1000 TG-UV FT-817ND FT-60R FT-897 FT-. I like the built-in battery backup feature to the controller and would like the rest of the rig to be easily operable off of 12v.
My questions are
-What are the most economical radios to use with this repeater?
-What is an economical antenna?

Thanks for your help in all this! I'm completely new to all this. I just started researching GMRS capability this week.

[mmckenna]

Building a repeater isn't an easy undertaking. There is a lot of work that goes into it, and if you haven't done it before, expect to make some expensive mistakes.
Not trying to discourage you, just trying to make sure you know what you are getting into. It's not uncommon for people to start down this path and give up. It's often best to see if there is an existing GMRS repeater in your area that you can try out first, before you start investing a lot of money into this.

So, the repeater controller:
Honestly, look flimsy. It uses VOX (voice operated) to trigger, which is a cheap way of doing it. Usually repeaters use a carrier operated relay to key the transmit circuit. Doesn't mean it won't work, just that it may be problematic.

The duplexer:
That is a mobile duplexer and would work, but I doubt the specifications that claim it has 1 dB of loss. Really high end ones we have at work have 1 to 1.5 dB. The specifications for this one are suspect.

For the radios, a couple of hand held radios will work, but they are not designed for the high transmit duty cycles that a repeater might see. This can result in overheating of the radio, or permanent damage. Portable radios would work for a low power system if you kept your expectations in check.

Antenna and feed line:
This can make or break your system. You really need to think this part out well. To get good coverage from a repeater its all about location and antenna height. You need to get your antenna up as high as you can. Since UHF tends to be line of site, your system coverage will depend on the location. Unless you have such a location, your coverage will suffer. Using an existing site can be expensive and dealing with noise and interference issues can get expensive. You need to invest in a good antenna, the best you can afford. A cheap antenna will provide poor results and will not last long. Coaxial cable is really important also. Cheap coaxial cable will cause a lot of your signal to be lost in the feed line. Since you want to get the antenna up as high as you can, you need to use a high quality feed line to get your signal up and down the tower. Cheap feed line will cause a lot of your received signal to be lost before it reaches the repeater.

If I was going to do this, I'd first see if there was a repeater in my area that I could use. Even having to pay a few bucks a month is going to be cheaper than building your own.
If that wasn't an option, I'd put most of my money into the antenna, feed line and duplexer as these can easily make or break your system. Cutting corners on these will limit how well your system is going to work.
For a controller, I'd find one that used the carrier operated relay, had a time out timer (although you can do that with the radio), and some more functions.
For the radios, I'd look for some used UHF mobile radios. Hand held radios are just going to be a hassle. With the upcoming narrow banding deadline, there are a lot of UHF mobile radios out there for sale used that are not narrow band capable, but this isn't a problem since GMRS isn't required to meet the narrow band requirements. You could pick up a pair of Motorola GM300 or similar radios for less than 50 bucks each. Find ones that have the full 16 pin connector on the back and it'll make interfacing to the repeater controller a lot easier. A mobile radio will be more durable and will put up with longer transmission times. It's also pretty common to turn the power on them down to help reduce heat issues.

It's a lot of work, but the results will reflect how much you put into it.

[aaronK]

Thanks for the reply! I have a good hillside location to set up. I've checked myGMRS and there are no current repeaters that cover my area. I searched GM300 on eBay and came up with this... Working Motorola GR300 450 470 MHz 40 Watt UHF Repeater | eBay
Thoughts?

[mmckenna]

If I was starting out with my first repeater, I'd probably go that route. As a package deal, you are almost getting everything you need. Those are proven and you can find spare radios really easy. GM300's are pretty solid little radios. I've got a few vhf units still kicking around that are going strong.
Getting it shipped programmed and ready to go would save you some of the headache. If you haven't set one up before, it can be a steep learning curve. Only issue is that Motorola radios require expensive programming software and cables. Good news is that you can get an after market cable cheap. Getting the software legally will be difficult as I think Motorola doesn't sell it any more. It would not be uncommon to find someone with the software that could make programming changes for you.

You'd still need the duplexer. The seller has one for sale. You do need to get that tuned for your specific frequency pair. The small mobile style duplexers work, but you would get better performance for the larger ones. Shopping for them on e-Bay might be a good option. Just make sure you get them tuned. With shipping, it might be risky to pay the seller to tune them for you only to have them shift in shipping. Better choice might be to buy them and take them to a local shop for tuning. At least that way you could be sure they were set up right.

Looks like you are off to a good start.

A few other things:
Running those radios at high power for long periods can be detrimental to their health. Often people will turn the power output down to help prolong their life.
Put your money into a good antenna, feed line, support system and duplexer. Don't skimp here. A bad antenna and cheap feed line will make even the best repeater work like crap.

Good luck!

[mmckenna]

Oh, and don't forget lightning protection for you system. Do some searches on that as it's been well covered. One lightning strike can destroy your whole system!

[KB7MIB]

Wirelessly posted (Mozilla/5.0 (X11; Linux i686; U; en-US) Gecko/20081217 Vision-Browser/8.1 301x200 LG VN530)

Just a note, not every GMRS repeater will be listed on mygmrs.com. Some owners don't want to be listed, others simply haven't been submitted. Monitor the channels for awhile, to make sure there are no repeaters active there.

[KB7MIB]

Wirelessly posted (Mozilla/5.0 (X11; Linux i686; U; en-US) Gecko/20081217 Vision-Browser/8.1 301x200 LG VN530)

You might want to use a VOX activated recorder to monitor when you're not at home or asleep or otherwise away from the radio. You don't want to set up on an occupied but seldom used channel!

[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+)

Just a note on the GM300, I strongly recommend running it at no more than about 15w before the duplexer, WITH high volume fans on the heat sink. The heat sink is small and the GM300, even a 25w (same heat sink) gets hot REALLY fast at 25w. Also hard line for the antenna run, and double shielded jumpers between the radios and duplexer.

A group I belong to has a bunch of 25w GM300/Maxtrac uhf ham repeaters running at 12.5w (80KM+ radius footprints) we have had few issues so far, but have always on high volume fans blowing on the transmitter heatsink.

[aaronK]

Thanks for the replies guys! Good call on monitoring channel activity prior to starting this whole thing.
As far as antenna, feed line, duplexer, etc, what are some good yet budget friendly options? I'm assuming that more expensive is not always better?

[aaronK]

As far as run time and heat disappation, from my understanding the repeater is only active when keyed up by another radio. Is that accurate? So as long as the radio traffic is low volume, the unit won't be running all the time?

[ywhic]

I ordered the simplex 30 second model from 888 last week.. just to test my KW 805DH 35w unit and some handhelds.. low and behold I managed to snag another KW 805D (25w) yesterday for $68 shipped.. I may need (after testing this simplex) to order the FDR1 duplex repeater to mate those 2 together (along with the same 50w duplexer/notch filter)....

Debating if I should use a 4w portable for RX and the Kenwood 805DH for TX (with duplexer/notch) and just utilize the other incoming KW 805D for my vehicle... hmmm..

[MOONBOOTS]

What are the most economical radios to use with this repeater?
-What is an economical antenna?


All the above tips are great, but setting up a repeater & "economical" can't be used in the same thread. Wherever you save money, performance will suffer. In this case, more money usually is better. You can save money by buying good tested used equipment, vs new cheap equipment. Good luck.

[quarterwave]

There have been lots of Motorola M120's on ebay this week. I snagged one for $27 shipped. I have 2 repeaters based on these, and one has been running about 40 watts out for the 16 years I have had it as a repeater TX...never a hiccup. I bought it new for this purpose when I worked at a M dealer. The cabinet has 2 cooling fans for circulation and I run a fan on the heatsink. It will self de-power when it is hot, but I have never had an issue in all this time. We don't use the repeater everyday, but sometimes it's busy.

There was a pair of Radius radios with a cheapy repeater cable on Ebay yesterday. Personally I use a repeater controller with delay and audio adjust (about $40) from MRE1032 on Ebay...works great. I am getting ready to replace my M120 based repeater with a MTR2000 and relagate the M120 to other services. I still have one more running about 25 watts out on a small coverage repeater at same site.

[MOONBOOTS]

Originally Posted by quarterwave

Personally I use a repeater controller with delay and audio adjust (about $40) from MRE1032

Kurt [MRE1032] is my go to guy for any cable I need. His stuff is top quality.

[aaronK]

Economical probably wasn't the right word. Value I guess? I realize you get what you pay for. But in my experience, money doesn't equal quality by default.

Thanks for all the tips guys! Really appreciate it!

[gewecke]

These are true dtmf programmable repeater controllers ,

Integrated Control Systems

73,
n9zas

[ywhic]

Ok.. I did a review on another site..

Mot GP350 (4w) with external BR-450 5/8 over 5/8 antenna on GP mount 35 feet up on chimney side with the RT-SRC1 simplex repeater at the house..

Car has a Tram 1170 5/8 over 1/2 ant with same GP350 (4w).. I got a solid 5 miles yesterday with it on GMRS.. I then changed the car antenna over to my KW 805D mobile and got 6.5 miles with that.. so... if doing this.. make sure your antenna that you are REPEATING from is as high as you can get.. it IS the limiting factor..

I'm waiting for my 10 amp Tripplite to get here to put the KW 805D in the house to see if the extra wattage out will boost the range.. (I have the KW wire from 888Radio sitting here)..

ETA: I do have a GMRS license..