Batboard

Please be kind, I am tring to learn all of this as I go.


Obviously we all know the Pro’s to having a repeater for our radios. I have never owned my own as of yet, but I have been asked by a few buddies of mine what it would take to start up a GMRS repeater. We would mostly use this for around town comm.‘s and for hunting ect. So beside the repeater and all of it’s hardware to boot what else do we need? How do you apply for a license for a repeater on GMRS? There is not anyone else with a GMRS repeater here that I know of so it should be easy to pick the frequency we would want for it (within the limits of GMRS). Another question what are the bad points of owning and maintaining a repeater. Like I said this would be my first so I don’t want to got into it completely blind. TIA for any information on this topic.

MY two bits worth:
My GMRS license is about 27 years old, so it has been a while.
There are 8 channel pairs starting at 462.55, with a new channel every 25KC.
I am on 462.625

The "family radio" channels are 12.5kc offset from the GMRS channels. Unless you have VERY good receiver selectivity on the repeater you may have problems with interference.

Your proposed use is exactly what GMRS (formerly Class A CB) is intended for.

I would suggest obtaining a copy of the FCC rules, and regs, which you must have any way.

The max power output is 50W to the antenna, which is sufficent for most purposes any way.

I would sugest monitoring the channel that you intend to use to determine that it has little or no traffic before you bother to construct a repeater on that channel.

As in real estate location is everything.
You will have to find a location for the repeater that you can afford.
Commercial sites have become quite expensive.

Bernie is right on, as usaul.

I mite add here one important point.

Make sure that the radio transmitter is FCC Type Accepted and meets the .0002% frequency tollarance.

Go the the FCC website and look for ULS, there you can apply online for your licenses. You can also follow the links there for the FCC rules, part 95 which covers the GMRS among others.

Look on Yahoo Groups for GMRS and GMRS Repeater groups.

also repeater-builder.com and repeater-builder group at yahoo.

as far as location I already have that and it is real cheap ( family owned land ) so that's no problem. I have 2 cdm 1250's that i was thinking of using for this project. I have a legal copy of CPS of them but how would i got about inputing all the info to these to "setup" the repeater part of it? i.e. Rx in one and Tx in the other. Would I have to get a rick for these radios? Many question's on this. Something new to play with. Thanks for the help thus far guys

At the most basic level, you could use your CDM1250s to make a basic repeater. As you surmised, you would use one for TX, and one for RX.

In addition to the radios, you would also need, at a minimum, a power supply , a duplexer to allow both radios to share one antenna, an antenna system, and some form of controller.

It is possible to just jump two mobiles together to make a dirt cheap repeater, however, you will be missing many basic (or required) features like hang time or automatic station ID. A R.I.C.K. would also work, but is probably (in my opinion) one of the worst choices in terms of features vs. cost vs. ease of setup, and still won't give you station ID, or remote setup and knock-down.

Another suggestion- since the CDM1250s are really a lot more radio, and a lot less repeater than you really need, you might consider trading them for a basic desktop repeater like the GR1225. Given the values involved, it would probably be pretty close to an even trade, and the GR1225 would give you a full repeater, with a power supply, cooling fan, built-in controller, etc. You would have to find one that came with an appropriate duplexer for your application, and it is a different RSS package to think about.

One good place that I might reccomend to do some reading about the fundamentals of repeaters is: http://www.repeater-builder.com/rbtip/

95.119e states:
(e) A station need not identify its transmissions if it
automatically retransmits communications from another station which are
properly identified.

So, no CWID is needed. PL and time out timer arre about all you need.

You might be able to find an older repeater all ready to go for GRMS (even on the right frequency) if you ask around a bit. We have 2 of them that are from a local shop that used to rent GMRS repeaters back when businesses could be on the service. They might be old, bit the play, and were FREE!!!

If you will be putting the repeater in a location that has no other radio equipment, the setup with mobile radios and a rejection duplexer will work fine. But, if you are going into a commercial site with lots of other stuff, then you really need to step up and get a good pass-reject duplexer and a quality radio.

We use RICK type repeaters for backup units. If you need help with the programming of the radios, let me know.

Josh

The CDM mobile radios do not meet the type acceptance for repeater or base station use due to insuficiant frequency stability.

Sec. 95.129 Station equipment.

Every station in a GMRS system must use transmitters the FCC has certificated for use in the GMRS. Write to any FCC Field Office to find out if a particular transmitter has been certificated for the GMRS. All station equipment in a GMRS system must comply with the technical rules in part 95 subpart E.

The FCC watches the frequency stability of repeaters and have inspected several that did not meet type acceptance aka 'certifiacted'.

How do you apply for a license for a repeater on GMRS?

You do not need a license for a repeater on GMRS, it is covered under your license.

Cam

This is the FCC site to look up a radio's FCC ID to find out what services it is type accepted for.

https://gullfoss2.fcc.gov/prod/oet/cf/e ... Search.cfm

It is a bit slow in providing results.

Josh

thanks for all the info everyone

There are excellent repeaters out there that are approved for GMRS, such as the Maxon SRC-40U. The cost, without duplexer, is just under $1000. It is a continuous duty 40 watt repeater.

One thing you might want to look into is the local hunting laws regarding the use of two way radios in hunting. I have read about some people being fined.

Here is one such post:

http://www.outdoorsdirectory.com/forum_ ... radios.htm