Dual band and GMRS antenna in one?

[VETCOMMS]

Is there such a thing for mobile radios?  I know hams have the dual band antenna but do they have an antenna that covers 2m, 70cm AND GMRS?

[BoxCar]

Yes and no. Check the bandwidth listed for the UHF portion of the antenna. If the bandwidth covers the frequencies needed then yes, it will work.

[VETCOMMS]

Ok, I think I saw a Bridgecom mag mount that covers it.  I'll keep looking.

[Lscott]

1 hour ago, WRTZ750 said:

Is there such a thing for mobile radios?  I know hams have the dual band antenna but do they have an antenna that covers 2m, 70cm AND GMRS?

As @BoxCar mentioned it's yes and no. Some antennas might work just fine even if the manufacture's specifications don't cover the frequency range. You'll need to test it.

I have an old, like 20 years, dual band Comet antenna that works great on both Ham bands, MURS and GMRS. Unfortunately they don't make it any more. I had purchased two at the time. One I used strictly indoors, never saw the outside and looks like new. If the one I have on the vehicle ever fails completely or gets destroyed I have a back up.

I did an SWR scan using a RigExpert AA-1000 antenna analyzer.

https://rigexpert.com/products/antenna-analyzers/aa-1000/

I was curious to see how it performed verses the manufacturer's spec's. See the attached files. The scans are the antenna as mounted on my old Jeep's roof rack cross bar.

CA-2x4MB Manual.pdf

[wayoverthere]

Yes...some antennas are more forgiving (wider range covered) than others. One example is the comet 2x4sr. Covers 2m, MURS, 70cm, and GMRS. On the downside, it's ~36" long.

Still available, as far as I know, in both nmo and uhf bases. (I'm partial to nmo for its wide availability, so I can swap whips at will.)

[marcspaz]

I use the Comet 2x4SR. I have one in UHF and one in NMO.

 

It works great in 2M, MURS, 70CM, and it has a 2.6:1 SWR or better on all GMRS channels, including the repeater inputs.  It has about 4dB of 'real' gain on the GMRS channels.

 

It is a compromise across the board to have it all on one antenna. 

 

UHF 

https://www.hamradio.com/detail.cfm?pid=H0-001424

 

NMO

https://www.hamradio.com/detail.cfm?pid=H0-011146

 

I also have a Comet M-24m that I use when clearance is an issue.  It woks better on GMRS than the Ham bands. But, as I mentioned, there is going to be compromise. 

 

 

[Lscott]

10 minutes ago, marcspaz said:

I use the Comet 2x4SR. I have one in UHF and one in NMO.

 

It works great in 2M, MURS, 70CM, and it has a 2.6:1 SWR or better on all GMRS channels, including the repeater inputs.  It has about 4dB of 'real' gain on the GMRS channels.

It's 2.6:1 on GMRS? That's high. I'm guessing you mean 1.6:1.

The antenna is a good wide band design, but it's a bit sensitive to the mounting location. Being a 5/8 wave it needs a good ground plane.

[marcspaz]

Just now, Lscott said:

It's 2.6:1 on GMRS? That's high. I'm guessing you mean 1.6:1.

The antenna is a good wide band design, but it's a bit sensitive to the mounting location. Being a 5/8 wave it needs a good ground plane.

 

No... it's 2.6:1 on the 467mhz channel.  I don't see a 1.6 on any frequency with that antenna. I think the best I get is on 2m, it's 1.7.

 

The advertised range stops at 465mhz and it's used in very limited circumstances. So, I'm not too worried about it. The UHF and the NMO are mounted in very different locations, but have near identical performance.  I also mo Ed them to a few different vehicles with the mag mount and there was very similar performance. 

 

As I mentioned, it's it's compromise to use it, but I don't worry about SWR until it's at 3:1. Then I consider tuning are replacing the antenna. 

[wayoverthere]

42 minutes ago, Lscott said:

It's 2.6:1 on GMRS? That's high. I'm guessing you mean 1.6:1.

The antenna is a good wide band design, but it's a bit sensitive to the mounting location. Being a 5/8 wave it needs a good ground plane.

I'll have to recheck mine, but I want to say it was 1.4 or less everywhere I tested. I have the spring kit, and it's mag mounted dead center on the roof of a single cab compact truck, so decent ground plane.

I also remembered I have a small diamond (nr72b, maybe?) that's advertised as dual band...grabbed it for it's small size (trying to to find a better performing dual band/limited clearance option than the Comet SBB1), and it's near 1:1 on uhf, and maybe 1.3 on gmrs. I say "advertised", because it's like 2.5-3 on 2m on the truck, but decent on a piece of sheet metal indoors. Haven't gone back out to see if it likes an "edge" in the ground plane like the compactennas apparently like, still waiting for a break from triple digit highs (they're saying 115 on Tuesday )

[marcspaz]

Dang... that's hot.  I'll have to show you guys what mine is doing when I'm back in VA. I don't have any of my gear right now, but Monday or Tuesday I'll shoot some video.

[gortex2]

I run the Larsen NMO 150/450/700/800 on my work trucks. Additionally the MSI Tri Band antenna sweeps pretty good on both 2M and 440 and GMRS. I'd use a commercial antenna before a HAM antenna most days. Just like the performance and quality better. JMHO

[VETCOMMS]

Thanks for all the good antenna options.  I think I'll stick with just the GMRS antenna like that Midland one with the 6db gain for now, I can't recall the model number.  Once I get my HAM license I'll think about these dual band antennas you mention.  Then again, I might be able to listen/monitor more frequencies with the dual band antennas as opposed to the Midland GMRS mobile antenna?

[BoxCar]

The best antennas for bandwidth are the ones designed for single band, commercial use. Dual  and tri-band antennas are all compromises made to tweak the antenna to work acceptably.

[KAF6045]

58 minutes ago, WRTZ750 said:

Thanks for all the good antenna options.  I think I'll stick with just the GMRS antenna like that Midland one with the 6db gain for now, I can't recall the model number.  Once I get my HAM license I'll think about these dual band antennas you mention.  Then again, I might be able to listen/monitor more frequencies with the dual band antennas as opposed to the Midland GMRS mobile antenna?

For receive, the main criteria is length -- longer antenna "captures" more input signal; tuning for frequency/SWR is less critical unless you are really into weak-signal work.

Transmit, OTOH...

[wayoverthere]

2 hours ago, WRTZ750 said:

Thanks for all the good antenna options.  I think I'll stick with just the GMRS antenna like that Midland one with the 6db gain for now, I can't recall the model number.  ?

Mxta26. I wish they still sold their 3db whip rather than the ghost, that worked well without being too tall.

1 hour ago, BoxCar said:

The best antennas for bandwidth are the ones designed for single band, commercial use. Dual  and tri-band antennas are all compromises made to tweak the antenna to work acceptably.

This. I've had very good results out of a single band Laird for 70cm.

[WRTH549]

 Yes & No, the accuracy of a true GMRS antenna, will do a better job, than trying to use three different frequencies accurately with one antenna. That's my finding.

[WRTH549]

I have a question, I made a J-pole antenna for my handheld GMRS radio, and used a Micronta 144/440 SWR/POWER METER, Radio Shack Cat.# 19-320, now this was a total experiment, and I went off from another J-pole design for a GMRS, and modified the antenna, having no idea if it would even work. low and behold, on the above mentioned, SWR meter, I got a reading 0n the Range side set @ 15 W of about 6 watts, and on the function side, set at SWR, I got a reading of 1.5, I roughly cut the wires, and had no idea if it would even come close to a match. I have not trimmed the wires for a final reading, almost don't dare to.....could I have done anything wrong, of is it possible I nailed it first time out?  ( See pictures below )  Long wire, after soldering into the SO-239 ends up 12" long, measuring from top of SO-239 to tip of wire. Short wire, after making loop for small bolt, washers & nut, is 3.5" long, from the bend to the tip. I also used 14ga wire, solid copper.  Measurements, are before final "trim-to-match."  Spacing between wires is 5/8".   Radio is a Baofeng UV-5G.    Thanks for any and all advice. Mike-KI4TOL / WRTH549

[KAF6045]

1 hour ago, WRTH549 said:

I have a question, I made a J-pole antenna for my handheld GMRS radio, and used a Micronta 144/440 SWR/POWER METER, Radio Shack Cat.# 19-320, now this was a total experiment, and I went off from another J-pole design for a GMRS, and modified the antenna, having no idea if it would even work. low and behold, on the above mentioned, SWR meter, I got a reading 0n the Range side set @ 15 W of about 6 watts, and on the function side, set at SWR, I got a reading of 1.5, I roughly cut the wires, and had no idea if it would even come close to a match. I have not trimmed the wires for a final reading, almost don't dare to.....could I have done anything wrong, of is it possible I nailed it first time out?  ( See pictures below )  Long wire, after soldering into the SO-239 ends up 12" long, measuring from top of SO-239 to tip of wire. Short wire, after making loop for small bolt, washers & nut, is 3.5" long, from the bend to the tip. I also used 14ga wire, solid copper.  Measurements, are before final "trim-to-match."  Spacing between wires is 5/8".   Radio is a Baofeng UV-5G.    Thanks for any and all advice. Mike-KI4TOL / WRTH549

Main point of concern... That RatShack meter may only be spec'd for 2m and 70cm bands, so could be giving widely incorrect readings outside of them. Not sure if it is the same model, the page shows 190-0320

Quote

MHz Ranges:
2m: ....................................................... 140 - 150 MHz
70cm: ..................................................... 430 - 450 MHz

In contrast, my MFJ-847 is listed for 125-525MHz.

If you intend to do much antenna home-brewing, you might want to consider EZ-NEC https://www.eznec.com/

 

[MichaelLAX]

1 hour ago, KAF6045 said:

Main point of concern... That RatShack meter...

 

Next you'll be calling their computer, the Trash-80! 

[MichaelLAX]

2 hours ago, WRTH549 said:

 

I have a question: Is that a Telecaster?!

[marcspaz]

5 hours ago, MichaelLAX said:

Next you'll be calling their computer, the Trash-80! 

 

Man, I had a TRS-80 model 1 from 78 to 82 until.  It launched my career as a computer scientist.  Love that system.

[Lscott]

So did I. Also had the matching printer that used the aluminum coated paper.

[KAF6045]

3 hours ago, MichaelLAX said:

Next you'll be calling their computer, the Trash-80! 

The Model-I deserved that appellation (processor in keyboard, memory expansion external using ribbon cables, monitor was a Sony [as I recall from my time working Sears pick-up desk] TV with the tuner board removed).

The Model-II (first attempt at a business machine using 8" floppies) was a bit of an improvement, but needed a bigger power supply or more shielding -- every time one made a read/write to the floppy the screen image would shrink/jitter.

Model-III was reasonable, especially once one installed LDOS (originally Lobo Drives OS) rather than the Mod-III TRSDOS. Model-4 was likely the epitomy for the Z-80 line -- coming with a licensed copy of L(S)-DOS (Logical Systsms DOS, after Lobo Drives fell off the map, as TRSDOS 6 I believe) I still have a Model-III/4 (upgraded CPU board, but original display and /larger/ power supply) in storage. I'd have to patch the OS disks to handle a new date range, and hope the drive heads don't snap off when spinning up

[MichaelLAX]

1 hour ago, marcspaz said:

 

Man, I had a TRS-80 model 1 from 78 to 82 until.  It lunched my career as a computer scientist.  Love that system.

Are you sure it didn’t dinner your computer career?! 

[marcspaz]

2 hours ago, MichaelLAX said:

Are you sure it didn’t dinner your computer career?! 

I was eating some Wendy's chicken nuggets when I was typing.  LOL

[MarkInTampa]

19 hours ago, KAF6045 said:

The Model-I deserved that appellation (processor in keyboard, memory expansion external using ribbon cables, monitor was a Sony [as I recall from my time working Sears pick-up desk] TV with the tuner board removed).

The Model-II (first attempt at a business machine using 8" floppies) was a bit of an improvement, but needed a bigger power supply or more shielding -- every time one made a read/write to the floppy the screen image would shrink/jitter.

Model-III was reasonable, especially once one installed LDOS (originally Lobo Drives OS) rather than the Mod-III TRSDOS. Model-4 was likely the epitomy for the Z-80 line -- coming with a licensed copy of L(S)-DOS (Logical Systsms DOS, after Lobo Drives fell off the map, as TRSDOS 6 I believe) I still have a Model-III/4 (upgraded CPU board, but original display and /larger/ power supply) in storage. I'd have to patch the OS disks to handle a new date range, and hope the drive heads don't snap off when spinning up

I had a job in high school at the local Radio Shack demoing Model-1's. Wrote a spreadsheet in VisiCalc for a local golf course to keep track of handicaps. We ended up selling over 50 Model-1's with that spreadsheet to golf courses all around the So Cal area.

I've still got a kinda rare Model-4P and a few others including a Osborne, Kaypro and a ultra rare Fujitsu Micro 16S in the closet.