my experience with GMRS so far

[BigDaveZJ]

Yeah I've seen the 3rd brake light mounts. They're pricey for what they are. I could put a short GMRS up there, but it just seems cheaper and easier to put a longer one in stake mount. I need to keep my overall height down too so I can fit the truck in my shop without smacking the antennas.

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[Billoftt]

Those brake light mounts are more expensive than my Kenwood TM-V71.

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[BigDaveZJ]

This looks like it would work: https://baofengtech.com/nagoya-tb-320a-38.5-fold-over-tri-bank-antenna

 

[Billoftt]

That isn't tuned for GMRS.

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[BigDaveZJ]

From the product page:

Optimal Frequency Range: 140-160MHz, 220-225MHz, 420-470MHz

While not tuned specifically for GMRS, GMRS is within it's optimal frequency range.

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[Billoftt]

I don't quite understand your goals here. You did say that you currently run the Midland antenna, are you having issues with it? How does it currently perform?

 

[BigDaveZJ]

It performs well enough, but it doesn't reach very far above the cab, hence me looking into longer antennas. The one I posted would reach farther over the cab, which would in theory perform better, and I wouldn't have to drill a hole in the roof of my truck and still be able to pull the truck in my shop.

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[Billoftt]

Just stick with what you have. Although an NMO drilled into the center of the roof is the "ideal" setup, we all have to deal with compromises on occasion, and this is your compromise. Will that extra two feet of height squeeze a bit more range? Yes. Will having all of your antenna above the metal roof and cab make the ideal RF pattern? Yes. Will how you have it now degrade both characteristics slightly? Yes, but if it is working well enough for your needs now, I wouldn't get too wrapped up about it and keep it the way it is for now IF that mounting placement is the compromise you have do deal with for now.

I have conversations like this a lot. I usually end up convincing people I know in person to go ahead and pull the trigger on getting their Amateur Technician License and sometimes they get wrapped up in antenna placement, gain, ground plane, etc. all the time. I just tell them for the most part, you will either be using repeaters or simplex when we are all in a close group within a few miles of each other. Just get a good quality 2m/70cm dual band antenna that is 1/2 wave on 2m and 5/8 over 5/8 on 70cm and put it on a fender or a stake pocket or a roof. A 1/2 wave doesn't need a ground plane and the 5/8 over 5/8 would need only 6 inches on metal for a ground plane and you probably won't ever use UHF to worry about it. The extra height from going from a fender to a roof on a truck won't matter too much when talking through a repeater that is 800 feet high anyway.

Likewise, high gain antennas do not benefit much on a mobile application on line-of-sight frequencies. GMRS has a LOS of around 3ish miles on a 6 foot tall roof. All the gain in the world still can't defeat the curvature of the earth. High gian antennas hav emore to gain when mounted higher as a base station or on a repeater station. This is not to say that you did not make a wise purchase with your Midland high gain antenna. I did verify through MidlandUSA that that particular antenna is phased at 5/8 wave over 1/2 wave and the extra length of your antenna does help get the signal over your roof-line and through your windows better what a 1/4 wave would have.

Just like Occam's Razor, with radios usually the simplest answer is the most likely answer.

 

[colodak]

I tell ya', that first time you drill a 3/4 inch hole in an otherwise perfectly good roof is quite a liberating experience. However, I do understand your apprehension.

If possible, see of you can find a local radio shop, i.e. the place that does the installs for the police/fire/EMS vehicles in your area and have them put an NMO on the roof for you. NMO mounts are very mechanically and electrically reliable with minimal insertion loss and a properly installed NMO will never give you any issues with leaking or anything like that. Plus, that form-factor is available on a plethora of different antennas for various bands. A few of the reasons why NMOs are widely used on service vehicles in Police, fire, EMS, Forest Serserv, DNR, etc.

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If the OP is wanting to go this route, since I know this thread is in Colo., he could contact AVTECH in Wheatridge, on 44th Ave just west of I-70, I'm not sure if they will work on non-police/fire vehicles, but he could try them.

 

[BigDaveZJ]

If the OP is wanting to go this route, since I know this thread is in Colo., he could contact AVTECH in Wheatridge, on 44th Ave just west of I-70, I'm not sure if they will work on non-police/fire vehicles, but he could try them.

Still not mounting it on the roof, and certainly not paying anyone to do it for me! ?


Got some good use out of the GMRS over the past week down in Silverton. Several members of my wheeling group are already planning on adding/switching to GMRS after seeing the performance and clarity gains over CB, especially with the handheld. For those familiar with the area, I was easily able to communicate with my wife in her JK in Silverton from our camper at the north end of Eureka campground. MXT115 with the antenna mounted on the ladder of my 5th wheel, and the MXT275 with magnet mount shorty antenna on the JK. 7.65 miles as the crow flies and no real LOS as the canyon up to Eureka has a decent curve to it. A buddy of mine kept having CB problems on the trail as well, so we lent him one of our GXT1000's so we could reach him via GMRS. The clarity, simplicity, range, everything just dwarfed the CB's.

I am getting some intermittent picket fencing out of the MXT275 in my truck. Not sure if antenna placement is playing a role in it. With the 5th wheel hooked up, the antenna is basically between the cab of the truck and the camper, so not ideal. But I'm still not drilling a hole in my roof!

EDIT: Also had an RTFM moment with the 275 in my truck and trying to use an external speaker. I have one in the truck already for my CB, and switched the cord over to the 275 for the drive down since my wife and I were only going to be using GMRS. Ended up using the CB to listen in to some truckers hauling wide loads that we were stuck behind for 30 miles, but that's another story. Anyways, the ext speaker didn't seem to work on my 275. I noticed there was a jack on the mic itself, but that would be annoying as all get out having another wire coming from the mic. So I read the manual when I got home and found out you have to actually turn on the ext speaker jack using the controls on the mic. You can have both the handset speaker and ext speaker on, or select just one of them. Cool feature I thought, should have read the manual better I guess.

 

[Billoftt]

I have a 115 and a 275 and I get some picket fencing out of both of them. It happens with the 1/4 mag mount and it happens with both a unity gain phantom antenna and a 5/8 wave antenna mounted to a grounded and bonded NMO mounted in the roof. I think it's just inherent to these less expensive models that use those cheaper all-in-one solid state components opposed to the separate components on the higher end radios. I am willing to bet the 400 probably doesn't do it as much.

Picket fencing is the one thing that AM has over FM, but it's a big enough thing that aviation decided to use AM.

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[BigDaveZJ]

When I turned off the 275 in my truck and used one of the GXT1000 handhelds, there was zero issue in talking with the 275 in my wife's JK. Kinda strange. Loaned one of the GXT1000's to a buddy of mine with a JL though and it was darn near impossible to understand him at all, even with him being within 1/2 a mile or so. So I don't know, lol.

I did get an NMO mount for my ZJ today. Have a Browning low-profile antenna showing up in a couple days. Going to mess around with that a bit and see if I can see a difference between the Midland 6db gain whip and the Browning, and will properly mount the NMO in the middle of the roof of my ZJ. If I like the performance of the low-profile unit I will probably just use that on my ZJ and then order an identical setup for my DD 5.9 ZJ so that I have GMRS there too. That'd put me at 7 GMRS radios, and I still need one for out in the shop.

 

[BigDaveZJ]

A wheeling buddy of mine was impressed with the GMRS on a recent trip and bought a couple GXT1000 handhelds and an MXT115. Got his GMRS license already too. Tried out the radios tonight. I had to get a little higher ground from my house but using the 275 in my truck with the 6db gain Midland whip in a stake pocket mount we were conversing easily at just shy of 12 miles across Metro Denver. I had great LOS from my position so I was kind of expecting it, but still super impressed.

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[dreadlocks]

Ive got a great view of Metro Denver at my place, if you wanna do some testing sometime hit me up.. I hear folks from all over the place from my vantage point.

 

[BigDaveZJ]

That'd be kinda cool, see if we can make it work. I'm in the vicinity of Arapahoe and Colorado, used the church parking lot just north of there to get great LOS over most of western Denver.