WRXB215

Adding a larger, correctly tuned and well-placed external antenna will almost always certainly perform better than the stock antenna, but depending on your terrain, and 3million other variables, you may or may not notice. With good line of sight, you might get 20 miles of farz on the radios using the stock antennas, but if you have a mountain at 21 miles, then no big antenna is going to get you 22 miles of farz.
Dont overthink it.. If you are getting the farz that you need with the stock rubber ducky antennas, then use them. If you need more farz, then connect to a correctly tuned and well-placed external antenna.
Queue the overly complicated, 10 paragraph responses that don't really address or answer the question:

Not planning on doing any super tight winds; I just spent two hours writing up a Quality Assurance report to Engineering on a landing gear harness with excessive bend radius.  As anal as we have to get with the fiddly bits on jets, I see no reason to not take the same precautions on my rig...and we run loads of coax in stacked runs.

Magnet mounts on 6M and HF don’t couple very well to the body of the vehicle. The cable ends up being part of the ground plane. On a 1/4 wave 6M antenna I ended up using a ferrite toroid near the magnet mount base to decouple the antenna. Otherwise moving the coax around resulted in significant SWR changes. 
 
I also paid a few bucks, at a flea market, for some magnet mount CB antennas, Little Wilson, with the idea of cutting them down for 10M. Finally gave up since the bandwidth was very narrow and the SWR jumped around every time I moved the coax a bit while adjusting the antenna.

This isn't a problem in the 400-500 MHz range. Both Randy and I have shared test results for this. Unless you plan on winding the coax to less than an inch in diameter while using some super cheap (unshielded) coax, it won't matter. 
Now, when you start getting down to 50 MHz to about 21 MHz, 8 inch to 25 inch coiled coax just spooled up and tossed aside becomes an issue with SWR.  That's why when we do CB installations, we use either a 9 foot or 18 foot cable and just snake the extra cable around the interior, trying to avoid half or full loops in the cable. The lengths are balanced 1/4 or 1/2 wave.

Around here 1 to 3 miles is normal in the city because of buildings, low elevation change and the curve of the earth. Normal distance in a flat area is 3.1 miles to the RF horizon. It's very unlikely you can send enough energy into the atmosphere to make up for those obstacles. And those same obstacles will defuse the signal you're trying to receive. 
 
Then there is the issue of RFI, which tends to overload your receive front-end, desensing it. So you can't hear the desired signals due to the radio trying to stop the RFI from over-driving the receive. 
 
Out in the burbs and countryside, I get 14-15 miles with just 5 watts. In town, it's anywhere from less than a mile to about 2.5-3 miles with 50w.
 
Significant elevation for a less obstructed signal path is your only hope of getting ant range in a typical city.

A good way to see the terrain between you and your friend is a line-of-sight tool like link below.  Scadacore.com had a better one, but their site seems to be down as of this post.  Our cabin in up by Alpena has some serious elevation changes (300') depending on the direction.  We can get anywhere from 4-10 miles using simplex with a vehicle mounted MTXA26 Midland MTX400 (SWR 1.1) and 15' tower mount MTXA26 Baofang HT (SWR 1.5).  I have done some testing and agree, its all about antenna height and terrain.  
https://www.solwise.co.uk/wireless-elevationtool.html

Power output is much less important than antenna and antenna placement. I easily get 20 miles to a repeater with a 5 watt handheld and rubber ducky because the repeater and antenna are on a mountain. 
I use the same antenna and mount as you on my vehicle. 
Are you in a vehicle or using this hardware in a house? You and your buddy should find a couple hills and see if things get better.

Welcome!
Rule #1: Have fun and don't get too hung up on the small stuff.

This kind of crap doesn’t belong here.

With ham radio you BYOR “bring your own radio” and there will be other people to talk to if that’s what you want.
With GMRS you have to BYOOP “bring your own other people.”
That’s not to say that you’ll never talk to complete strangers in distant and exotic neighborhoods not so far away, but it’s not really why GMRS exists.
 

Post the zip file. 🙂

Hello folks, here’s my long but complete sales post:
 
I recently scored an “open box” Motorola XTL5000 UHF system on eBay. It was advertised as open box, as new never installed. My original plan “may” () have been to program and install, but other projects have intervened and it will just sit in the box, so I think this unit is better put to use by someone.
 
This one has the new “5” remote head unit in black, which is apparently more desirable. It appears to include all the wiring cables, brackets, mic, external speaker, etc. It’s all wrapped up and appears new to my eye.
 
I also picked up a programming cable.
 
In researching the Motorola programming software, I came across some semi-recent posts that indicated - since these radios are no longer in production - Motorola would provide the software at no cost. It took some time to navigate Motorola customer support, but the did in fact provide a link to download the genuine software from them at no cost. When I sell the radio I’ll forward that link to the buyer. [edit: it is not a link, but a copy of the actual software, sent to me by Motorola].
 
Now since I haven’t installed or connected the unit, I can’t confirm it’s status, but it appears as new and based on the sellers comms, how it’s packaged, and how it looks I have no reason to doubt that all is well.
 
The unit is MOTOROLA UHF XTL5000. 380-470mhz - model M20QSS9PW1AN
 
I’ve attached the sellers photos as it’s wrapped up and ready to roll. I have all outstanding feedback on eBay and several forums; watches, firearms, and vehicles. I’ll gladly speak by phone, FaceTime, etc. to ensure you are comfortable. I’m too old and my reputation too good to mess around.
 
Edit: SOLD!
 
Thanks for checking out my ad.
 
Ed
 

That's what Amateur Radio bands are for. 

I think your forgetting one important factor:  they were all BELOW GROUND.  The EM burst was strongly attenuated and dissipated by, well, the ground.  That was by design...the NORK government doesn't go out of it's way to piss off it's sole sponsor, the PRC.  Our government  learned from Starfish, and applied those lessons to future testing.
 
Exoatmospheric detonations won't be so attenuated, at least for some distance.  

@Blaise,
So, I finally installed Rattlegram. Everything you said is exactly what they represent. I don’t understand how the speakers and microphones in smartphones can transduce ultrasound, much less the speakers and microphone in a two way radio. I also don’t understand how the radios modulate signals in the ultrasonic range. 
I’m intrigued. 

I'm happy with this install.  The remote head mount fits in the bottom front console box with no fasteners.  Radio is mounted under the passenger's seat.  No wires are showing anywhere except what you see here and the coax from the bumper to the antenna. Antenna coax and direct power from battery thru floor drain grommet. Antenna on spare tire mount. Remote speaker wire plugs into Uconnect radio aux input ⅛" socket and functions thru the Uconnect to the Jeep's factory speakers that can BOOM the audio.  Ran the coax along the frame and behind the passenger's rear tire skirt to get to the bumper.  The radio is programmed to recieve tons of stuff outside the ham bands for monitoring: CB, GMRS/FRS, marine, air, business vhf,  and TV alternate sound. 

Because arguing about it here generates over 20 responses in 5 hours. You can't get action like that from the FCC.

GMRS is not a "hobby" GMRS IS intended for people to bring their own audience (ie; your group while off-roading) GMRS is NOT for people that "want to make contacts" It seems you have been misinformed about what GMRS is for, and what its primary purpose is.  It sounds like amateur radio or the Grindr app are more of what you are looking for.

The more I hear, the more it sounds like your coax is somehow jacked up and your antenna is now possibly too short. Antennas that are slightly too short or too long, (which is unlikely with an out-of-the-box MXTA26), shouldn't generate a 10:1 SWR reading. Bad coax, bad grounds, even one tiny wire from the braid or center conductor shorting out at the connector will jack up your SWR that much. If you can take the coax completely out so it is not connected to anything, there should be no continuity between the center pin and the outer shell of the connector on either end of the coax. It should be an open circuit.

Welcome! With a GMRS license and a new radio, you are well on your way!

Hello, new guy checking in. I received my license on 09/21 and my starter Baofeng the next day. New to the GMRS world but been using radios for over 30 years as a LEO and .Mil. Happily retired from both now. Looking forward to going down this rabbit hole. 

I've said this before. As much as sending text messages over GMRS sounds like a neato idea, (which it kinda is), it's yet another example of trying to make GMRS something it was never intended to be. As much as amateur radio gets maligned on this site, the list of ways GMRS wants to be like amateur radio keeps growing. Linked repeaters carrying transmissions into other states, internet setups like Zello, and texting apps like Ribbit. The problem is that GMRS has a very limited 5 mhz slice of the UHF band, and it's channelized. Cramming more and more into it is eventually going to overload it. I'm a bit of a purist, so in my humble opinion, leave it alone and use it for, as the sum of all human knowledge, Wikipedia, says, (I say that with tongue firmly planted in cheek), "short-range two-way voice communication and authorized under part 95 of the US FCC code".

Don't let the CDC find out. 🤣

Cheater! 😉

Anecdotal, I know, but in my own experience there are very few people I wheel with that are amateur radio operators.  All of them use FRS or GMRS when they wheel anyway.  Moving to amateur service for offroad is seriously going to limit who you talk to on the trails.
If you are not worried about that or don't trail ride, I suppose it's a non-issue.
 
 
If you are planing on using VHF and UHF, the same limits apply as in GMRS.  While you can run 1,500 watts on amateur bands, the extra power doesn't do much if the LOS isn't there.  Most of the time, VHF simplex around me, is limited to between 3.5 and 20 miles depending on terrain.  However, I few days ago, from a mountain top I talked to someone almost 250 miles away.  GMRS works the exact same way.
The only thing that gets you more range without repeaters and mountain tops is HF.  You can work the world with just a few watts... but you won't talk any further locally there either, as LOS still limits local comms.  Usually once you hit the LOS barrier, either you need 40m, 80m or 160m NVIS to talk, say 20 to 350 miles.  Otherwise, you aren't talking to many people inside the 350 mile radius there, either.
 
 
What specifically are you looking to do.  Myself and many others have a ton of experience over many decades in different areas.  There is a good chance we can help if we know what you want to do.