I have sort of a unique GMRS antenna question.

Charlie_V

New member
I am new to fcc licensed radios and my spouse will barely use one, much less study for an amateur or ham license. So I got a gmrs license and some 5w (I thiygt, they are actually 2w) handhelds. We are often on our 75 wooded acres in the middle of a cellular hole. The rest of the time we are at our city place. Obviously, those handhelds offer great simplicity to encourage her, and they have FM radio so there's that, but the range is not great through the trees.

I'm getting up to speed quick and have learned how to access open repeaters. Time for higher wattage mobile radios (50w).

Vehicle 1 is a lifted Excursion. Ten feet of metal on top. I already have an NMO cell booster antenna smack in the center of the usable space above the roof console/done light. 2 feet behind that is about 5.5 feet of solar panels that sit 3 inches above the roof and have aluminum frames. I'd be glad to explain why I have solar panels but that exceeds the scope of this part of the forum. Solar panels are on a non standard, DIY rack with crossbars constructed of utilistrut. There are no rails in the sides. I was concentrating on making it hard to see what they are and keeping them safe from theft before I contemplated mobile radios. Rack is attached to smittybilt mounts that fit in the Ford roof rack track. I've read all that I can but I am just dumb about antennas at the moment. Presumably, putting a dual band (FRS/GMRS) antenna at 50w next to my cell booster antenna is a dumb idea. Also, presumably putting a bracket on a solar panel frame above the roof, or an nmo mount next to a solar panel, is a dumb idea. So what I am left with is hanging an angle bracket off of a smittybilt mount, an nmo at the back of the truck, or a lip mount somewhere. I'm a little shy about the 50w right in my face, so maybe a lip mount on the rear hatch???

Vehicle 2 is a true billy goat, but with a fiberglass roof and a sun roof. And a moon roof for that matter.

Vehicle 3 is even more of a billy goat, but has a lot more electronics than the others, and has three glass roofs!

Can someone guide me in how to mount antennas that won't cook my brain, ruin the swr, cook the radios, or otherwise make me look like a dummy to my already skeptical spouse?

I should have mentioned, our driveway is an adventure. Half mile requiring constant maintenence, on a hill, with trees barely missing my 7.5 foot tall Exursion (and usually missing my approximately, additional 12 inch tall cell booster antenna). Tall, high gain antennas are out of the question. I have no problems drilling holes in my roofs and have the nerves of steel and appropriate equipment to do so.

Thanks for reading.
 
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Frdmskr

Adventurer
Vehicle 2 and 3 look for an angle bracket off the front quarter panel for an NMO. Run the antenna thru the firewall to the radio when you run the radio power to the battery thru the firewall.

Rig 1 all you need is 6-8” of separation from the cell antenna and you are fine. So you can rig it like the other vehicles or set it forward of the cell antenna.


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Charlie_V

New member
Vehicle 2 and 3 look for an angle bracket off the front quarter panel for an NMO. Run the antenna thru the firewall to the radio when you run the radio power to the battery thru the firewall.

Rig 1 all you need is 6-8” of separation from the cell antenna and you are fine. So you can rig it like the other vehicles or set it forward of the cell antenna.


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Thank you!

So no issues having a 50w antenna in front of the windshield?

I stood on the stairs behind my office for a top picture of rig 1 and here's what I have. Does this change the answer at all? I appear to have more room than I thought in the front area and the new antenna should still fit over the overhead console. I could run it to the back area (still torn over which power system, truck or solar, to hook up to, so I could go either way; truck preferred simply because the solar runs a medical/convenience item that is always on 24/7).

I already have #8 silicon sheathed wire, fuse blocks, and 40 amp relays, and know how to use them. I suppose I need to check what sort of draw these radios will have at 50 watts but surely that's plenty).

If I only need 8 inches I may be able to squeeze it between the booster antenna and the solar panels. Any problem with that if I have 8 inches all around?

Should I put the new one to the side instead of sticking with the centerline?

Thanks again.

526786
 
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Frdmskr

Adventurer
I am thinking that splitting the difference between the cell booster and solar panels should be ok. I’d be more worried about RF noise off the solar panels and will defer to others who have more knowledge and experience with them than I.

As for 50w at the windshield, it’s not ideal but it will be fine. The roof is always the best but adapt and overcome as needed.


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BigDaveZJ

Adventurer
If you're only trying to cover 75 acres it won't be hard at all. We use GMRS for very similar reasons as you do, and the Midland GXT1000 handhelds should be more than sufficient, even on the low power TX setting, even from inside of a vehicle.

I certainly understand the benefits of a base/mobile unit in a vehicle though, and an antenna like this one would get the job done on your Ex: https://www.amazon.com/BROWNING-BR2445-450mhz-465mhz-Pre-Tuned-Low-Profile/dp/B00DIH6HRC/ref=sr_1_4?keywords=gmrs+antenna+low+profile&qid=1562861917&s=gateway&sr=8-4

Here's my thread on my experience with GMRS: https://www.expeditionportal.com/forum/threads/my-experience-with-gmrs-so-far.205826/
 

Charlie_V

New member
Why would you think there would be a problem with a antenna in front of the windshield???
Two reasons: first, blocking the signal since I see GMRS described everywhere as "line of sight"; and second, blasting myself with the signal. I know 50w is not an incredible amount of energy but it is more than I have ever contemplated close to my head than anything previous (cell, CB, etc.).
 

Charlie_V

New member
If you're only trying to cover 75 acres it won't be hard at all. We use GMRS for very similar reasons as you do, and the Midland GXT1000 handhelds should be more than sufficient, even on the low power TX setting, even from inside of a vehicle.

I certainly understand the benefits of a base/mobile unit in a vehicle though, and an antenna like this one would get the job done on your Ex: https://www.amazon.com/BROWNING-BR2445-450mhz-465mhz-Pre-Tuned-Low-Profile/dp/B00DIH6HRC/ref=sr_1_4?keywords=gmrs+antenna+low+profile&qid=1562861917&s=gateway&sr=8-4

Here's my thread on my experience with GMRS: https://www.expeditionportal.com/forum/threads/my-experience-with-gmrs-so-far.205826/
I have read your thread before and didn't realize it was on these forums until just now. I just read it again. In fact, that thread was what finally gave me peace in choosing GMRS. Thanks for that!

We have a similar setup insofar as our rural place is near the top of the area (though nothing like Colorado in altitude). I considered Midland handhelds and base/mobile units but went with double the number of BTECH ones in the end and I recall the coin flip went to BTECH because of the batteries, extended batteries, and 12V adapters. I figured out to the use CHIRP and they are all easy to use now.

I got Tram dual frequency antennas for the vehicles because I wanted to be sure we could get NOAA through those at 162.xx. and, of course, we could run the lower range frequencies through them if we didn't care about FCC rules (which we do... care). We have open repeaters available here but the mobiles have at least the potential to reach each other immediately after leaving the interstate (where cell service begins to be weak) between our city and rural homes even without the repeaters.
 

Charlie_V

New member
I am thinking that splitting the difference between the cell booster and solar panels should be ok. I’d be more worried about RF noise off the solar panels and will defer to others who have more knowledge and experience with them than I.

As for 50w at the windshield, it’s not ideal but it will be fine. The roof is always the best but adapt and overcome as needed.


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That's a great observation. I hadn't considered RF interference from either the mobile or our terrestrial solar setups at all. In fact, your comment was a real show stopper in my mind because I would normally have considered an issue like that and it hadn't even entered my thinking.

So I looked into it.

Based on what I've read, the panels do not introduce RFI, but the associated controllers and inverters most certainly do in a basically unregulated manner. The Excursion has a controller, 200ah battery, and a 3/5000w inverter--the latter two on a diamond plate project board in the cargo area--there is also a DC refrigerator always on.

So I took a handheld GMRS, set the squelch to zero, turned everything on, and in an exceptionally unscientific manner listened for interference inside the truck and then holding the handheld at the likely antenna location and I'll be darned... there was ALOT more interference inside the truck with the inverter on and with a very slight load (work light plugged in, then tried with a grinder plugged in and running) than on top of it. So that's very interesting and also makes me conclude that I need to run the mobiles off of the truck power instead of the solar power.
 

Frdmskr

Adventurer
That's a great observation. I hadn't considered RF interference from either the mobile or our terrestrial solar setups at all. In fact, your comment was a real show stopper in my mind because I would normally have considered an issue like that and it hadn't even entered my thinking.

So I looked into it.

Based on what I've read, the panels do not introduce RFI, but the associated controllers and inverters most certainly do in a basically unregulated manner. The Excursion has a controller, 200ah battery, and a 3/5000w inverter--the latter two on a diamond plate project board in the cargo area--there is also a DC refrigerator always on.

So I took a handheld GMRS, set the squelch to zero, turned everything on, and in an exceptionally unscientific manner listened for interference inside the truck and then holding the handheld at the likely antenna location and I'll be darned... there was ALOT more interference inside the truck with the inverter on and with a very slight load (work light plugged in, then tried with a grinder plugged in and running) than on top of it. So that's very interesting and also makes me conclude that I need to run the mobiles off of the truck power instead of the solar power.
Well that is a good experiment. Look at properly shielding and grounding the controllers to block the noise. There is some stuff out there on home installs but honestly I am Not familiar with anyone doing much with with mobile solar yet.


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Charlie_V

New member
This is the sort of stuff that boggles my mind (re: antenna placement): https://stormtrack.org/community/threads/antenna-spacing.8855/

Totally off topic, one reason we are in a rush is that we are likely to be leaving for Louisiana in the next few days to help rip sheetrock out of a relative's house that is sure to flood, again, this weekend. Last time we had zero cell service the entire week we were there and it was super inconvenient to not be able to reach each other.

And even farther off topic I just found out my best friend has terminal cancer, so I'd like to get this project done and make his last month his best ever. This was earlier today on a happy trip to the vet that turned into a sad trip.

527017
 
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Charlie_V

New member
Well that is a good experiment. Look at properly shielding and grounding the controllers to block the noise. There is some stuff out there on home installs but honestly I am Not familiar with anyone doing much with with mobile solar yet.


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Me, either.

The mobile solar was actually a warm up for terrestrial solar at our country place to supplant our electrical service. When our electricity is out because infrastructure is damaged (full length poles blown out of the ground and dragged twice already this year), it is usually out for at least week during which there is no well water, no nothing unless I spend a gallon of gas an hour in our generator. I am a quick study but solar has never really hit my radar so I just ordered some things from Amazon and gave it a shot. It worked.

However, I also needed a way to keep both myself and medications cool. An amazing side benefit is that we can buy frozen and refrigerated things at Sam's Club or wherever and then eat out or take our time getting home without risking melting and ruining. Adding an inverter so I don't have to move a generator around for small tasks and so we have light everywhere was icing on the cake. It keeps the truck marginally cooler in the sun (panels shade a big part of the roof). The solar system will charge or jump start the truck batteries, tractor, backhoe, etc. It was well worth the expense and general jackasssery of its appearance. Fortunately, I do have a "normal" vehicle to drive when this won't do.
 
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DaveInDenver

Expedition Leader
And even farther off topic I just found out my best friend has terminal cancer, so I'd like to get this project done and make his last month his best ever. This was earlier today on a happy trip to the vet that turned into a sad trip.

View attachment 527017
Man, I know how tough that is to deal with. He's a handsome one, best to you and him.
This is the sort of stuff that boggles my mind (re: antenna placement): https://stormtrack.org/community/threads/antenna-spacing.8855/
There are two things you're worrying about here. Antenna placement relative to other antennas (and ultimately the affect this has on other radios). This is fairly easy to predict.

Something to consider is that mobile there's almost zero chance you can get ideal antenna separation. So you can only do your best. There are few thing IMO you should do strictly, though. Antenna whips shouldn't ever physically touch if you're using them to transmit. If two receiving whips touch it's not going to hurt anything but shorting a transmitting antenna to another whip will be a great risk to ruining one or maybe both radios. So consider how they're going to be flopping around or getting bent over on overhanging branches when you're locating them.

There's been some good discussions and posts before about this, so you might search the sub-forum.


Your other issue is interference. Solar panels won't generate interference but the controllers certain can. This interference can radiate from the cables connecting the panels to the controller or on the output side to the battery, that's hard to predict until you actually test the system. The best solution to interference like this is to make sure all your connections are solid, cables are only as long as they need to be and that you terminate grounds or shields that are available.

Then take care running cables for everything. Keep as much space between the solar system and radio systems, distance is the most effective solution. Don't bundle everything into one single run and when cables have to come near cross them at 90° and avoid having them parallel for long lengths.
 

Charlie_V

New member
Man, I know how tough that is to deal with. He's a handsome one, best to you and him.

There are two things you're worrying about here. Antenna placement relative to other antennas (and ultimately the affect this has on other radios). This is fairly easy to predict.

Something to consider is that mobile there's almost zero chance you can get ideal antenna separation. So you can only do your best. There are few thing IMO you should do strictly, though. Antenna whips shouldn't ever physically touch if you're using them to transmit. If two receiving whips touch it's not going to hurt anything but shorting a transmitting antenna to another whip will be a great risk to ruining one or maybe both radios. So consider how they're going to be flopping around or getting bent over on overhanging branches when you're locating them.

There's been some good discussions and posts before about this, so you might search the sub-forum.


Your other issue is interference. Solar panels won't generate interference but the controllers certain can. This interference can radiate from the cables connecting the panels to the controller or on the output side to the battery, that's hard to predict until you actually test the system. The best solution to interference like this is to make sure all your connections are solid, cables are only as long as they need to be and that you terminate grounds or shields that are available.

Then take care running cables for everything. Keep as much space between the solar system and radio systems, distance is the most effective solution. Don't bundle everything into one single run and when cables have to come near cross them at 90° and avoid having them parallel for long lengths.
Thanks for your thoughts re: Blue. Hes a beautiful dog inside and out and the leader of our small pack. The sort of dog that doesn't need a leash, ever, trusts but doesn't like other humans, trains the other dogs, and seems to know what you're saying and doing. He will be missed.

My solar setup was slapped together and I haven't grounded anything except through what occurs in vehicle attachment. I'll pay attention to that this weekend. My panels should be grounded through the roof setup unless paint prevents it, which is entirely possible.

Renogy panels with Renogy connectors combine the three 100w panels and the panel frames are all connected to each other with bolts to prevent lift. I selected this particular panels for size. I shot for a no drill installation because I was too lazy to mess with my headliner. The combined wires (2) enter the truck by running to the hinges on the back hatch (perfect space to pass them and they are safe from crushing. A small length of eternabond tape keeps them from moving). Around the gasket, to an existing grommet that enters the sheet metal and then the cabin by the spare tire. The project board is 3/4 plywood that I clad in diamond plate by just beating it slowly around the edges and attaching with adhesive and then screws. The project board is attached to the spare tire via long bolts in unused lug holes on the spare tire. The spare tire attaches to the vehicle with a bare, huge, eye bolt, so, theoretically, the entire project board is grounded to wheel, the wheel is grounded to the eye bolt setup, which then grounds to the body. I used a test light and it grounded on the project board. The controller and inverter are both mounted directly to the project board with metal screws. However, I did not make a ground wire from the ground points on those devices to the project board directly, since they are both in physical contact with the metal project board. Do you think more is needed from an RF or ground perspective? I am all ears. I watched a few videos and read some reviews on Amazon... That was the sum total of my research.

I still haven't drilled for the antenna and now I am leaning toward a delta configuration, placing the new hole slightly rearward of the cellular antenna and on the passenger side because it would give me more separation. I can swap the antenna locations if I just adapt the SMA connector on the end of the cellular NMO... The cellular is generally at 700-850mhz so its ground pane needs are small, if I read the confusing articles correctly, and that would put the GMRS antenna in the catbird seat.

Antennas were not a thought when I put the solar panels on.

My thought on placing the antenna passengerward is to get it away from some drive through overhangs. The trees that arch my driveway will just do what they'll do. Antennas are cheap.

Maybe I am overthinking this and just need to drill a danged hole.
 

DaveInDenver

Expedition Leader
Do you think more is needed from an RF or ground perspective? I am all ears. I watched a few videos and read some reviews on Amazon... That was the sum total of my research.
Shielding is good. That means metal that blocks RF. But it needs to be continuous and any openings have to be smaller than the wavelengths will be a place noise can leak out. But remember it works both ways, you can shield the solar but you can also cover coax and radio power cables with metal jackets to protect it, too. There's nothing you can do about antennas, those of course have to be open to the world.

So point is make sure any gaps are pointed away from antennas and important cables.
I still haven't drilled for the antenna and now I am leaning toward a delta configuration, placing the new hole slightly rearward of the cellular antenna and on the passenger side because it would give me more separation. I can swap the antenna locations if I just adapt the SMA connector on the end of the cellular NMO... The cellular is generally at 700-850mhz so its ground pane needs are small, if I read the confusing articles correctly, and that would put the GMRS antenna in the catbird seat.

Antennas were not a thought when I put the solar panels on.
It's an unfortunate byproduct of physics that the roof is the best place for antennas, solar panels and racks. Can't they just all get along? A few inches here or there are probably not critical. On my last truck I had two whips on the roof (a pickup, so a smaller surface). I have not yet drilled holes and my thinking is a triangle like you're describing or if I only go with two whips they'll be across the back rather in line down the middle.

I will say, though, the middle is nice because almost everything is designed to have maximum clearance in the middle. So they rarely hit anything.
My thought on placing the antenna passengerward is to get it away from some drive through overhangs. The trees that arch my driveway will just do what they'll do. Antennas are cheap.
Like I say, lay it out as best you can and don't worry. I've mentioned it before in other threads when installing radios and antennas you have to be able to live with it daily and if the ideal layout irritates you it won't matter at all how it performs. Running into overhangs is one of the most irritating things.
Maybe I am overthinking this and just need to drill a danged hole.
That's usually what I do, so I am the wrong person to give advice... It is most definitely possible to over think and paralyze yourself into inaction. :)

But yeah, probably. There isn't a perfect design or installation. Do your best guesses up front, practice good workmanship (this is really important, clean, solid work helps a lot) and fix any major issues that arise.
 
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