davidotoole

@WRVH932 hey there. My first advice is to study the FCC regulations themselves, here is the relevant subchapter: https://www.ecfr.gov/current/title-47/chapter-I/subchapter-D/part-95/subpart-E and I also made a spreadsheet with an overview of the rules (see attachment.) The rules are going to be the foundation for everything you do, although it doesn't cover ins and outs of choosing equipment, etc. What kind of radios did you get? Anyway, I'm not able to help with repeaters, but hopefully someone else here will know what to do. gmrs.pdf

Thanks @Over2U and friends for your comments and help

Well I have been looking at external ones that connect to Android via Bluetooth.

Hey @WRWI380 that is good to hear. I don't know much about antennas, I bet someone here will though!

I'm purchasing a waterproof/dustproof tablet with built in multi-satellite GPS for use on the trails along with our GMRS radios and geo-data recording with GIS software. But I've been told that for best accuracy it's best to use an external GPS unit. Are there any GPS experts here who might be able to recommend a good Bluetooth GPS that works with Android?

@KAF6045 Thanks so much for your advice. Yeah, we've decided to drop the FRS idea for now. And I'll use Channel 4 instead.

Hi @WRWI380Some radios have a code scanner that will help you figure out which code is being used. But I would think that the group publishes the code somewhere? Can you check the webpage you found the group on? Or it could be that your transmissions were indeed not strong enough...

HI @WRWI380, although I do not know how to use repeaters, I do have one general suggestion. It might be helpful if you made a new question in the "Technical Discussion" forum at the top level, with a link to the video or videos you are having trouble following, and a description of what goes wrong when you try to follow the video. As for the repeater problem, it could be that the people you were listening in on, were using a CTCSS/DCSS code that you weren't transmitting, thus they wouldn't be able to hear you. I hope you can find someone knowledgeable on the board who can help answer your questions about repeaters. Although I'm not terribly knowledgable myself, I would be happy to answer other GMRS questions that don't involve repeaters.

Whoa. I just checked the map and the trail head I was planning to use for this test, is only actually about 175 feet lower than the peak. But if what you are saying is true, then I could possibly talk to someone at my house from Mt. Pisgah over 2 miles away. Since my elevation is about 400 feet lower than the peak, I might be able to make it happen.

@73blazer Yes, this forest isn't so big or deep, encompassing about 100 acres, and the amount of wetlands means that some areas (particularly the area where we did our test yesterday) are partly devoid of trees. But at Mt. Pisgah here in town we should be able to separate up to about 0.75-1.0 miles in denser forest if we straddle town boundaries, and we'll explore transmitting from the 715 foot high peak to a trail head about 0.8 miles south as well. Nearby Upton State Park should be an even more more interesting testing ground... it's 2,600+ acres! I will let you know what happens.

Interesting. I'll have to choose my FRS model carefully then. Actually, I'm starting to wonder if I should even bother with FRS for this use case, because we only need one person on each squad with a radio, and we already have 3 GMRS licensees in the group.

Hi and thanks again for your report. My Beofeng GMRS-9R radio complies with the regulations regarding power and bandwidth on channels 8-14, and we'll be using channel 18 on narrowband when 2-watt FRS handsets are in the mix. It is good to hear that range shouldn't suffer dramatically with narrowband.

@73blazer One additional question: did you get a chance to compare narrow versus wide band?

@Blaise I wish you the best for your group. I have put up our new web page here: Trails Adventure Team perhaps there will be useful information and ideas.

Sure, go ahead. I'd like to give you Excel, ODF, and CSV formats as well so that you can modify or convert it. GMRS and FRS radio regulations matrix - Main operational regulations.csv GMRS and FRS radio regulations matrix.ods GMRS and FRS radio regulations matrix (3).xlsx