Split group communication with GMRS

[DwnSth]

Not sure if this should be in this forum or in radios etc.
Normally our group splits up (8-10 each) when hitting trails to limit size. All of us are using GMRS radios with a smattering of CB's and maybe one ham. I've noticed that published GMRS repeaters are few and far between at many off-road parks (Windrock, Hot Springs, Hidden Falls). Haven't found any GMRS repeaters around Moab either. Occasionally we can talk to the other group if conditions are perfect but most times we are not so lucky. Are there repeaters we may be not finding? Also, I've wondered why the off-road parks don't have an emergency channel/repeater set up that covers most of their property.

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[Jeepeto]

Portable repeater box like the Retevis RT97 would probably serve you well. Place in a high location for best chance at line of sight and put a good antenna on it.

Moab is a different beast. Communications would be very difficult depending on where you were in relation to the other group due to varied terrain and just physical distance. If you have a couple hams in the group, they might have a shot at APRS “text message” style communication.

 

[jblackst]

There's a GMRS repeater adjacent to Windrock, Oak Ridge 725. W4KEV is the operator and it's listed as open use on 141.3.

https://mygmrs.com/repeater/5178

I would make sure to join mygmrs.com, as it seems to have a very up-to-date repeater listing.

 

[DwnSth]

Portable repeater box like the Retevis RT97 would probably serve you well. Place in a high location for best chance at line of sight and put a good antenna on it.

Moab is a different beast. Communications would be very difficult depending on where you were in relation to the other group due to varied terrain and just physical distance. If you have a couple hams in the group, they might have a shot at APRS “text message” style communication.

Thanks! We'll have to look into a mobile repeater for some of our trips. Looking on mygmrs for any rules etc. about setting up a mobile repeater (antenna height limits etc). I would think we could set up a large flag pole mast antenna off of one of our RV's. Have much research to do on this subject. If anyone has set up a portable unit it would be great to hear any real world experience.

 

[DwnSth]

There's a GMRS repeater adjacent to Windrock, Oak Ridge 725. W4KEV is the operator and it's listed as open use on 141.3.

https://mygmrs.com/repeater/5178

I would make sure to join mygmrs.com, as it seems to have a very up-to-date repeater listing.

Thanks! mygmrs looks like a great resource. I'll be back at windrock next month and will see how it works out there. Have you successfully used that repeater?

 

[Jeepeto]

I use a push up fiberglass mast for portable. It’s an MFJ-1916, I set it up similar to the video linked below. It works really well, is plenty sturdy and very easy to set up and take down. I don’t believe you’re limited to anything less than this (34’ for the MFJ-1916). Obviously if you can get permission to set up at the top of a hill, you’ll have the best reception from a higher starting point.

 

[Jtclayton612]

You could also try different gain antennas for different terrain, it *may* help with how it’ll shoot out the waves in a different way.

that being said the south/southeast kinda sucks because of all the foliage cover, it just plays merry hell on the Gmrs frequencies.

 

[jeepdriver99]

Not sure if this should be in this forum or in radios etc.
Normally our group splits up (8-10 each) when hitting trails to limit size. All of us are using GMRS radios with a smattering of CB's and maybe one ham. I've noticed that published GMRS repeaters are few and far between at many off-road parks (Windrock, Hot Springs, Hidden Falls). Haven't found any GMRS repeaters around Moab either. Occasionally we can talk to the other group if conditions are perfect but most times we are not so lucky. Are there repeaters we may be not finding? Also, I've wondered why the off-road parks don't have an emergency channel/repeater set up that covers most of their property.

I wish there was a single simple answer to all this. The reality is each challenge may have a unique solution.

I like the idea of repeaters that cover most of the properties. But setting up a repeater is fairly involved. The cost would be a factor when you consider the equipment and power to run the equipment. Would a single repeater suffice or would multiple repeaters be needed? Since the GMRS frequencies are in the 460 mhz band, the antenna(s) would need to be at the highest point possible such as the highest hill where the majority of the property can "see" it. Each property would have to be owned or leased by the repeater owner and power run to that property. You also have a control issue. Would the repeater be licensed separately like HAM repeater are? Would the repeater be monitored all the time? Would the height of the antenna interfere with repeaters outside of the area? These challenges would need to be considered and answered.

 

[Jim1964]

If all you need is basic messaging like when/where to reconnect, then a Garmin Inreach -or competitive product- in each group would be a more reliable system.

If you’ll need an extended conversation, not so much.

 

[jeepdriver99]

Portable repeater box like the Retevis RT97 would probably serve you well. Place in a high location for best chance at line of sight and put a good antenna on it.

I hadn't seen these before. Neat idea. But I think the RT97 is more for something like a camp site or event where handhelds are used. It's only 10 watts and a normal mobile radio will have more power and transmit further. This looks like its so you can set up in a central location as a static post and have hand held radios at 5 watts or less use the repeater to talk to another hand held. That would work with mobile sets too but the repeater would probably need to be stationary.

 

[Jeepeto]

I hadn't seen these before. Neat idea. But I think the RT97 is more for something like a camp site or event where handhelds are used. It's only 10 watts and a normal mobile radio will have more power and transmit further. This looks like its so you can set up in a central location as a static post and have hand held radios at 5 watts or less use the repeater to talk to another hand held. That would work with mobile sets too but the repeater would probably need to be stationary.

From what I understand it should work almost as well. Position and elevation is everything in line of sight communication. The power output of 10 watts vs 50 is negligible (approx. 1 S-unit or 7db, this could be offset through the use of a decent antenna) and when the signal is being blocked by physical barriers like mountains, trees, buildings, etc. the repeater could be useful. Obviously not as powerful as a 50 watt repeater but in the real world it should be almost as effective in bridging the signal, and will use much less battery.

 

[jeepdriver99]

From what I understand it should work almost as well. Position and elevation is everything in line of sight communication. The power output of 10 watts vs 50 is negligible (approx. 1 S-unit or 7db, this could be offset through the use of a decent antenna) and when the signal is being blocked by physical barriers like mountains, trees, buildings, etc. the repeater could be useful. Obviously not as powerful as a 50 watt repeater but in the real world it should be almost as effective in bridging the signal, and will use much less battery.

Good luck.

 

[J0E]

If all you need is basic messaging like when/where to reconnect, then a Garmin Inreach -or competitive product- in each group would be a more reliable system.

That's what we use. Something like the InReach guarantees you can communicate (except in N. Korea) anywhere. The automatic tracking points are useful too.

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