Antenna guidance needed.

[Caryt]

I have a Jeep Gladaitor with a AluCab canopy Camper with 2ea 200w solar panels.

They are mounted on 3 rails, rails are Alumnum as is the camper and frame work of the ridged panels.

I have a Midland MXT 575 and will be using this to talk to others on overlanding trips from desert to mountains. 

I would like a antenna no taller than 18" and would like it mounted if possible on the middle rail or the rail closest to the cab. Note the Jeep tops are fiberglass so not mounting their..

I also will be runing a Kenwood TM-V71A so if anyone has knowledge on it ..same location for its antenna. 

I won't be using both at the same time and don't want just 1 antenia for both. 

I would rather not mount anywhere else.

Antennias will be permanently mounted.

 

Thanks!

[BoxCar]

You only need to post the query once. Having the same question in multiple places makes it difficult for you to learn of good suggestions/answers to you issue.

[tcp2525]

On 7/16/2025 at 2:05 PM, Caryt said:

I have a Jeep Gladaitor with a AluCab canopy Camper with 2ea 200w solar panels.

They are mounted on 3 rails, rails are Alumnum as is the camper and frame work of the ridged panels.

I have a Midland MXT 575 and will be using this to talk to others on overlanding trips from desert to mountains. 

I would like a antenna no taller than 18" and would like it mounted if possible on the middle rail or the rail closest to the cab. Note the Jeep tops are fiberglass so not mounting their..

I also will be runing a Kenwood TM-V71A so if anyone has knowledge on it ..same location for its antenna. 

I won't be using both at the same time and don't want just 1 antenia for both. 

I would rather not mount anywhere else.

Antennias will be permanently mounted.

 

Thanks!

Smart man! That's a really nice setup you have. You bought a V71a, the best dual band radio in the history of amateur radio. As for antennas, get the PulseLarsen NMO2/70BLarsen for the V71a and a simple 1/4 wave NMO mount for GMRS and you will be extremely happy.

https://www.hamradio.com/detail.cfm?pid=H0-000565

[SpeedSpeak2Me]

You'll have issues trying to accomplish this with a single antenna that is limited to 18" (or so).  You can use the location for a GMRS antenna, but the 2m/70cm antenna for the Kenwood will be much taller.  Reason being is that you don't really have a good ground plane.  With GMRS you can get away with using a 1/2λ (wave) antenna.  It won't require a ground plane to be efficient, and they easily meet your height requirement (about 10-11" tall).  For the 2m/70cm antenna to get one that's 18" it's going to need a ground plane.  A model like the Comet SBB2NMO will actually cover* the 2m/70cm and GMRS (both simplex and repeater inputs), but it is a 1/4λ for 2m, and 5/8λ for 70cm.  Both of which need a good ground plane.

For the 2m/70cm if you went taller (40") you could get something like the Comet SBB5 or Diamond NR770HBNMO (basically the same antenna), which for 2m is 1/2λ and for 70cm it is 5/8λ over 5/8λ, so no ground plane required.  However it is 40" tall (with a fold-over mount).

*This is speaking from personal experience, as I have both the Diamond and the Comet SBB2NMO.  The Comet is on the trunk of a car, close to the edge where it meets the rear window, but I am directional to the sides and rear of the car.  It is fine for population dense areas with lots of repeaters, though its performance is compromised going towards the front of the car (no ground plane).  When traveling (road trips) I swap in the Diamond and being directional is no longer a factor.

[nokones]

You will need to use two antennae, one for the 70cm freqs and one for GMRS. You should mount each antenna on the side of each cowl near the "A" Pillar using the Rugged Radios mounting brackets and NMO mounts. Don't use the cheap stuff get the Laird Mount and Cable from a reputable Radio Electronics Dealer. As for the GMRS antenna since it appears you are only concerned with GMRS for the trail, you should get thd Midland MXTA25 or the MXTA26.

Attached is a picture of my Highband VHF antenna on the side near the cowl and "A" Pillar. Also attached is a Laird Lip Mount NMO mount I use for my UHF DMR freqs. The Phantom antenna is a Laird.

Just make sure that the mounts have chassis ground continuity without the coax cable connected to the radio.

[Caryt]

Sorry I didn't get a notice of a reply. Yes I plan on 2ea Antenna's. GMRS will be used trails and desert exploring. 

 I assume since the solar panels are mounted above the alumnum roof is the reason it will not work to provide a ground plane.

So..Could I add this http://Nagoya GPK-01 to gain the ability to mount on the crossbars? https://www.youtube.com/watch?v=CUV6p5nfK3c&t=191s

Would the Nagoya also work for the 2m?

 

 

[dosw]

6 hours ago, Caryt said:

Sorry I didn't get a notice of a reply. Yes I plan on 2ea Antenna's. GMRS will be used trails and desert exploring. 

 I assume since the solar panels are mounted above the alumnum roof is the reason it will not work to provide a ground plane.

So..Could I add this http://Nagoya GPK-01 to gain the ability to mount on the crossbars? https://www.youtube.com/watch?v=CUV6p5nfK3c&t=191s

Would the Nagoya also work for the 2m?

 

 

I have the GPK01, and really don't use it. First, you wouldn't drive with that thing. Its radials wouldn't stand up to highway speeds, or if they do, they would thrash wildly, destroying the finish of everything within their reach.

Second, I had pretty limited success with it providing an adequate ground plane. With my Comet CA2X4SR-NMO it worked alright for UHF but was no use for 2m. With my others antennas it lowered SWR only a little. With my Laird TE B4505CN "no ground plane" antenna it seemed to make things a little worse. 

Third, it doesn't provide a good weather seal for NMO mount antennas unless they have minimal bases like the Comet.

 

You're better off getting a no ground plane antenna such as the Laird TE B4505CN (for GMRS), or the Larson NMO-2/70 (for 2m, 70cm, and adequate GMRS), if you're ground plane challenged. 

[Lscott]

On 7/16/2025 at 2:05 PM, Caryt said:

I have a Jeep Gladaitor with a AluCab canopy Camper with 2ea 200w solar panels.

They are mounted on 3 rails, rails are Alumnum as is the camper and frame work of the ridged panels.

I have a Midland MXT 575 and will be using this to talk to others on overlanding trips from desert to mountains. 

I would like a antenna no taller than 18" and would like it mounted if possible on the middle rail or the rail closest to the cab. Note the Jeep tops are fiberglass so not mounting their..

That could be a rather interesting install. The solar cells are basically diodes so I'm not really sure how that would affect any RF that would reflect off them, if at all. Then there is the issue about any RF getting into the charge controller, oops.

The cells might tend to rectify the RF. The rectified waveform would be rich in harmonics so there is a remote chance the installation would be a rolling RF interference generator. I know some have tracked down very strange RF noise issues which were later found out to be caused by rusted metal junctions, again acting like a diode, on a tower generating the harmonics.

Yes this can happen. In WWII GI's made "Fox Hole" crystal radios using a razor blade for the diode detector. The metal "cat whisker" on the blue coating, which is really an oxide of iron, formed the PN junction.

 

[Caryt]

OK guess I'll have to mount them up front hood area..darn. Or I could get a rack for the area in front on the roof  and mount the antenias and my starlink. 

Or could that possibley cause a issue with the solar panels? Don't think it would bother the Starlink?

Thanks for bearing with me on this..

[Lscott]

1 hour ago, Caryt said:

OK guess I'll have to mount them up front hood area..darn. Or I could get a rack for the area in front on the roof  and mount the antenias and my starlink. 

Or could that possibley cause a issue with the solar panels? Don't think it would bother the Starlink?

Thanks for bearing with me on this..

I can't say with any degree of certainty that mounting the antenna over the solar panels will result in any negative effects. My point was to mention there could be some. The sure test is try out a temporary installation. That could be as simple as a magnet mount sitting on the cross bar while parked. If there is any issue with the charge controller it should show up as soon as you key up the radio at high power. You would monitor the output of the charge controller for any anomalous behavior.

I have a couple of these to monitor the output of some panels I have and the charge going into the battery bank, or discharge out of it. If you don't have one I highly recommend you get it for testing and monitoring. I got the version with the Anderson Power poles. They also have them with the MC4 PV panel connectors too.

https://powerwerx.com/watt-meter-analyzer-inline-dc-bare-wire 

https://powerwerx.com/watt-meter-analyzer-inline-dc-powerpole

https://powerwerx.com/watt-meter-analyzer-inline-dc-mc4

[Caryt]

I have a Redarc Redvision system so can keep track of the system.

With the unknows, rack over the removable panels may be the best answer. 

Looking at this one, Sherpa Moonlight shorty. I'll plate the bottom rack to creat a ground plane about 24x54+-.

If I go this way plate out of Alumnum or Steal? I'll powder coat either way.

[SteveShannon]

9 minutes ago, Caryt said:

If I go this way plate out of Alumnum or Steal?

It doesn’t matter as far as a ground plane, but if you use steel you can use a magnetic mount. 

[Caryt]

10-4, Thanks for your guidance.