SteveC7010

That is alot of words.  I may have skipped reading one or two as i really only use it for family comms.  My official travel channel is whichever one we agree on ahead of a trip.

1) It's allright.
2) It's allright. GMRS can be used for whatever purpose by anyone. Being this kids, cute moms of said kids, ugly angry fathers of said kids, sad hams, road flaggers, valet parking lots, you name it. It's a free country.
3) No, there is not. However, there is sort-of an agreement, explained by gortex2. And there is a certain youtube influenzer pushing something else. It is a free country. But you can always use a scan feature of your radio.

This is like the old joke about how 3 people can keep a secret. It works as long as two of them are dead. 
 
That seems to be the only way it’s going to happen on GMRS, agreement on a travel channel.

dead horse beater
 

I admit to using: a Motorola CDM1550LS+ mobile, a XTS2500 handheld, and a XPR7550e handheld, adding in GMRS to make them more useful to me. 

Yeah, if you are going to be messing with radios to any great extent and your not going to be buying radios and repeaters that are new.  You need to look at an old XP laptop being as necessary as a screwdriver or a Cresent wrench. 
Yes, they are old and not supported.  But while you can do work around's with DOSBOX, and other things on the newer operating systems, then you are getting into needing to understand PC's at a higher level as well to get things done.  And that adds complication to getting things done.
I have a couple old ToughBook laptops that are XP and Windows 7 that I use for programming.  They are rugged and well suited to be taken out and worked with.  Batteries are still available for them so that's the route I went.  As others have said, that stuff is cheap to get and is a good investment. 

They need to explain custom channel. There is no "other GMRS/FRS" channels other than the ones listed. My guess is maybe they use a unique PL or DPL tone on one of the channels to keep it to your group. Ask them what they mean by custom channel. Once you get that info we can help you program your radio. 

Being blunt, there are no "custom channels" on GMRS or FRS radios. A channel can be "customized" by adding tones for receipt and transmission of messages between users. Adding tones means you are requiring a user to have the same tone to use the channel in the same manner as the others but does not guarantee any type of privacy or exclusive access.

?

MURS = Simplex. Period.

I love how folks get on forums and try to change services that have been in place for years to make it do what they want to do vs finding a service to do what they want to do. 

From a regulation point of view there are only 5 MURS allowed frequencies. A repeater would tie up two of them. Add in more repeaters the open simplex channels would be gone.
Then there is the technical issues. For a good repeater system you need to use a split frequency. Currently the Ham 2M VHF band, that's just below MURS, the repeaters use a 600KHz split, which requires some very good cavity filters to achieve it. The only MURS band split that will work is one channel from the 151MHz block and one from the 154MHz block. Then to really screw things up the 151MHz block is restricted to narrow band FM while the 154MHz block is wide band. Also there are NO purpose made MURS specific radios that can even do split frequency operation. That leaves just old Part 90 radios. And it's iffy those can be legally used on MURS, all dependent on on the FCC grant date.

In the first place, we don’t all agree. In my opinion MURS is intended for short distance unlicensed simplex communications. Allowing repeaters drastically changes that and would make it harder to use those five channels for short ranges. 
The fact that a licensed service like GMRS is permitted repeaters doesn’t justify MURS repeaters.  Repeaters aren’t permitted on any unlicensed services that I know of. I’m not sure why anyone would want to spend a couple thousand bucks to put a 2 watt repeater on a tower anyway. 
I just don’t understand what you’re trying to make MURS into.

I wouldn’t do an SO-239 to NMO fitting if it’s going to be exposed to the weather, unless you do an excellent job of weatherproofing.  I would do an N fitting on the outside.  They are a sealed fitting.  And then I would order the right length of LMR 400 with a factory end on each end.
Actually, I would just use a factory cable with an NMO fitting all sealed up on the end of it.  I know it’s going to have more loss per 100’ than LMR400, but for a 13 or 15 foot cable it’s inconsequential.

You are way over thinking this. A standard quality NMO mount will be fine for the vehicle. The Laid mount that has been linked in other posts is perfect for your use and will cost less and perform just as well. There is absolutely no reason to use LMR in a vehicle install. Even in our command posts with many radios we dont run LMR. Its all quality NMO mounts. They are made to go above the headliner and take about 5 minutes to install in most new vehicles. 

Correct!
Cross band repeat is okay because it’s all within the Amateur Radio Service. As far as I can tell, Cross Service Repeat is not permitted for any of the Personal Radio Services. 
Definitely repeaters are prohibited in MURS.

Templeton, you have been given numerous explanations about how repeaters work. By introducing theoretical and ambiguous concepts and situations, you are confusing yourself. Most repeaters do one thing. They receive your weak HT or mobile's signal, they amplify it, and send it out on a different frequency. That's it. The best ones are high up so they have a massive coverage area. 

Clear your browser cache and history. 

Uh, since when is RG58 bad for UHF on a mobile radio ? There are hundreds of thousands of Police, Fire, EMS radios thru out the US that have an NMO with RG58 on them in UHF, 700, 800 Mhz. I have 6 NMO Mounts on my truck and 4 of them are RG58 standard Motorola NMO mounts. 2 are LMR as the new multiband came with it. 

I would take the reviewer's results with a grain of salt.
Nothing against them (and call me jaded if you want), but I also wouldn't put it past the companies making sure the units going out to be reviewed are "healthy" examples, compared to what gets shipped to the average buyer.

One that’s not currently in use if you want to find a quiet channel to communicate with friends and/or family. You have to do some monitoring to determine this  
if you’re looking to reach out to chat with others, you’ll have listen to determine which channel they are using for chat. 

The answer is specific to your immediate area so any info from those of us not in your backyard is not relevant or reliable.
 

You asked a question. It was answered succinctly by @marcspaz and exhaustively why by @Lscott.
You don’t need to worry about the extra thickness of the rubber.
What additional help would you like?

If they are “bubble pack” radios, they are automatically low power on 8 through 14. They are built that way and can not be adjusted by the user. Thus they are totally legal.

There are so many better ways to communicate in an emergency these days so if I am using GMRS for an emergency it is because nothing else is available. In which case the channel I can contact someone on is going to be my emergency channel. 

The FCC stopped issuing paper licenses years ago.
Sign on to the ULS, search for your call sign, and you can access a PDF copy of the license (as I recall it tends to favor "unofficial/reference copies", but there should be an option to download an "official" copy). Print & trim the paper.