Help me choose a GMRS antenna

[rnArmy]

I'm looking at this little Midland MTX115 GMRS radio for an upcoming trip:

https://midlandusa.com/product/mxt115-micromobile-2-way-radio/

I've already got a small Comet dual band HAM antenna mounted on the side-view mirror of my Jeep TJ, but it doesn't cover the GMRS frequencies. So I'm looking at two different GMRS antennas (or antennas that cover GMRS frequencies) unless someone has a better suggestion. I've read good things about both of these.

This 40" one by Comet: https://www.hamradio.com/detail.cfm?pid=H0-011146&oi=0

And this 6db gain 27.5" one by Midland: https://midlandusa.com/product/micromobile-mxta11-6db-gain-antenna/

I don't plan on mounting an antenna on my Jeep's roof.

 

[Billoftt]

I would check to see if you are resonant on your current dual band antenna. Out of the two, I have confirmed that the Midland is a 5/8 over 1/2 so it shouldn't give ground plane issues.

I also bought that same radio and I experienced bad picket fencing while moving above 10 mph. Midland replaced it without issue. I would be very interested to learn of your experience.

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[rnArmy]

This is my current Comet dual-band antenna. It is 144 / 440 MHz range antenna.

COMET SBB-5NMO

144 / 440 MHz Black Mobile Antenna - 38 Inches Tall - NMO Mount

www.hamradio.com

This other Comet CA-2x4SR dual-band antenna is a little taller, and has a range of 140 - 160 / 435 - 465 MHz (which better covers the GMRS frequency range of 462 - 467).

COMET CA-2X4SRNMO

2 Meters / 440 MHz 40 Inch Broadband Mobile Antenna 140 - 160 / 435 - 465 MHz NMO

www.hamradio.com

Folks seem to love both antennas (and I am so not the expert). The Midland 6db-gain antenna is only about 28" tall, and with my antenna being mounted on the side-view mirror, it won't stick up higher than the roofline. This Comet CA-2x4SR antenna is 40" tall, so I'm wondering it that extra foot will make a difference.

 

[dreadlocks]

I use the CA-2x4SR for GMRS and APRS, it performs quite well.. I've conversated simplex w/people on top of a mountain 30 miles away w/5w using 2m..

I'm also using it for my mobile GMRS repeater and APRS Digi in the trailer, and it does well enough for what it is.. both have springs and are mounted on a frontrunner mount that falls over on impact.

 

[DaveInDenver]

Have you swept that antenna @dreadlocks to verify their bandwidth claims? I know Comet and Diamond do some interesting stuff so I don't necessarily disbelieve but 30MHz 2:1 bandwidth on 70cm for a dual-band antenna with a claimed gain of 6.2 dBi is pretty dang wide. That's not too much worse than the performance of a plain 1/4λ (normally around 12% or so) and that won't have any gain.

 

[DaveInDenver]

FWIW, ran VHF and UHF sweeps across my standard Larsen NMO2/70B. Claimed specs are 144-148 with 3.8 dBi and 440-450 with 5.2 dBi. I have my coax terminated with a PL259 so some of the artifacts on UHF are probably due to that.

Actually looks like it would be ideal for 2m ham and GMRS to be honest.



Between cursor 7 (438MHz) and 4 (471MHz) looks to be where the antenna is best with a slight excursion just over 2:1 at 455MHz). Looks long, I think I could trim a bit off.



It's mounted at the base of my windshield on the left side. Terrible location, no question.

 

[dreadlocks]

I dont have the equipment to sweep bands like that, I do have a nice external SWR meter tho I should go check what it says for GMRS.. I believe its got some good gain even in GRMS range, I was communicating simplex w/handhelds over about 10-20 miles on our Labor Day Caravan back into town... one memeber of our party got stuck in traffic and ended up WAAAY behind us, every time I started climbing a pass I was able to raise him 20-30 mins behind us and he had one those cheap $16 china handhelds inside his car.. I dont believe the vehicle that managed to keep up w/me was able to hear him at all on his china handheld.. so it was all dependent on my superior antenna and radio.

 

[Billoftt]

The only equipment you need to plot a graph is an SWR meter, a pencil and some graph paper. It just takes a wee bit more time.

 

[rnArmy]

I use the CA-2x4SR for GMRS and APRS, it performs quite well.. I've conversated simplex w/people on top of a mountain 30 miles away w/5w using 2m..

I'm also using it for my mobile GMRS repeater and APRS Digi in the trailer, and it does well enough for what it is.. both have springs and are mounted on a frontrunner mount that falls over on impact.

Yeah; this is probably the route I'll go.

 

[Billoftt]

[/QUOTE]
The Midland 6db-gain antenna is only about 28" tall, and with my antenna being mounted on the side-view mirror, it won't stick up higher than the roofline. This Comet CA-2x4SR antenna is 40" tall, so I'm wondering it that extra foot will make a difference.
[/QUOTE]

Not too much difference, I imagine. It would be more of a difference on my Xterra because I have a metal roof and metal A pillars and metal B pillars and metal C pillars, etc. But on your TJ, both the vinyl soft top and the fiberglass hard top will be invisible to the RF, so being above to roof line will not be as important as it would for me. The only metal you have to worry about is the windshield frame and the roll-bar and that is a lot less.

 

[Joey G]

FWIW, ran VHF and UHF sweeps across my standard Larsen NMO2/70B.

Nice. What hardware did you use for that? I’ll buy an antenna analyzer one day, just curious what people are using.

 

[DaveInDenver]

Nice. What hardware did you use for that? I’ll buy an antenna analyzer one day, just curious what people are using.

I used a DG8SAQ network analyzer. I own a VNWA3E model, handy little tool.

DG8SAQ VNWA 3 and 3EC Models

DG8SAQ VNWA 3 and 3EC models and packages available.

www.sdr-kits.net

 

[dreadlocks]

man why does all the cool ham crap require windows..

 

[DaveInDenver]

man why does all the cool ham crap require windows..

Yeah, in this case there's really no way around it for their tool. They do have Linux software although I have not personally tried it. I think it just uses WINE, though.

If I was buying one now it might something like a pocketVNA, which also has Linux and Mac software.

pocketVNA - portable Vector Network Analyzer - home

portable vector network analyzer Ghz 2-port

pocketvna.com

But I gots what I got and spending $500 again isn't happening. Unless someone with Windows wants to buy my VNWA...

 

[Billoftt]

But I gots what I got and spending $500 again isn't happening. Unless someone with Windows wants to buy my VNWA...

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