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DRAX

Rank I

Enthusiast I

261
Monticello, IL
First Name
Hogan
Last Name
Whittall
Ham Callsign
W9DRX
First “galvanic corrosion”... it wasn’t improperly installed, I would say improper mount used... I used chrome mount and the supplied screws... not realizing they weren’t stainless steel... problems started arising after the corrosion was present. By the time I figured it out, I had to patch my roof... after lots of thought, I ended up getting a NGP antenna so I could glue my mount to the patch. I think I made it sound like it was a ground plane issue when it’s not... if you go read back to the Ford document you linked, fasteners need to be aluminum or plastic... hence used a plastic boat mount and a NGP antenna because bonding the connector back to the roof was going to make matters worse.

next you mention power source... I’m running 8” of 4 gauge wire between my power supply and radio... and 12” of wire between power supply and battery. I’m running 12 turns of both the positive and negative wires through separate T240-43 toroid. 1/2” ground strap bonds my radios, atu, and power supply to a common ground bus. From the ground bus I am running 000 welding cable to a grounding Rod array of three 8’ grounding rods buried 6’ deep bonded with the same 1/2” grounding strap.

Now back to the RFI issue... it was a two fold broblem as well.. first the galvanic corrosion caused a bad grounding connection which made The antenna more susceptible to RFI interference... second problem was once the corrosion started it ate its way back along lines under the roof where the electrical wires and coax cables ran (probably more due to water leaking than due to electrical problems.

So my solution to all these problems was very simple... use a piece of plastic to isolate the antenna mount away from the aluminum, glue the plastic and rivet using aluminum buck rivets, and use a NGP J-pole antenna. All of this is documented very well in my hamshack thread.

btw... I must be doing something wrong... I made a 2 meter voice contact last week at 110 miles at 10 watts with a 5200 foot mountain between us.
Again, I'm not saying you're doing anything wrong if you're getting the results you want. I think you're misunderstanding some basics and forgetting that correlation isn't causation which is causing you to do some unnecessary work or make some false assumptions. It feels like you still think the ground plane has something to do with electrical grounding. It doesn't. Or the discussion about having to bond the body to the frame (already done at the factory) and creating a ground plane because aluminum doesn't work as one (it does). Or that the galvanic corrosion caused RFI due to a "ground problem." The ground plane is only for transmitting, it has nothing to do with receiving and it has nothing to do with electrical grounding.

Do what works best for you and your vehicles. Just trying to clear up some misconceptions about ground planes vs electrical grounds and what works as a ground plane. The antenna size (1/4 wavelength, 1/2 wavelength) also determines if a ground plane is needed or not. Don't mistake not needing a ground plane with it being a NGP antenna. They are two different things.

Sorry to be pedantic, I just don't want people to go around thinking a ground plane has anything to do with electrical grounding or RFI. Totally unrelated.

Anyway, not here to argue or talk in circles, I was just trying to clear up what appeared to be some misunderstandings. Take care!
 

M Rose

US Northwest Region Director
Member

Traveler III

4,756
La Grande, Oregon, USA
First Name
Michael
Last Name
Rose
Member #

20990

Ham Callsign
KJ7MFV
Again, I'm not saying you're doing anything wrong if you're getting the results you want. I think you're misunderstanding some basics and forgetting that correlation isn't causation which is causing you to do some unnecessary work or make some false assumptions. It feels like you still think the ground plane has something to do with electrical grounding. It doesn't. Or the discussion about having to bond the body to the frame (already done at the factory) and creating a ground plane because aluminum doesn't work as one (it does). Or that the galvanic corrosion caused RFI due to a "ground problem." The ground plane is only for transmitting, it has nothing to do with receiving and it has nothing to do with electrical grounding.

Do what works best for you and your vehicles. Just trying to clear up some misconceptions about ground planes vs electrical grounds and what works as a ground plane. The antenna size (1/4 wavelength, 1/2 wavelength) also determines if a ground plane is needed or not. Don't mistake not needing a ground plane with it being a NGP antenna. They are two different things.

Sorry to be pedantic, I just don't want people to go around thinking a ground plane has anything to do with electrical grounding or RFI. Totally unrelated.

Anyway, not here to argue or talk in circles, I was just trying to clear up what appeared to be some misunderstandings. Take care!
You’re the one who keeps bringing up the ground plane.. I keep saying my problem was and is with dissimilar metals.

I also stated that the water leak caused by the dissimilar metals then fallowed my wiring and other things under the roof to cause more issues... also as Mike stated and so does one of those links posted earlier by you, the body doesn’t form the GP, but the lowest metal structure... so again the easiest way to properly set up an antenna on an aluminum bodied vehicle is to isolate the antenna from the body and bond to the frame so that no Galvanic Corrosion occurs...

you’re also misinformed if you think the GP doesn’t in fact have eclectically characteristics. Take a light bulb center conductor and place it on bare metal in the car body and run a jumper wire from its housing to the tip of your antenna... key up the mic and see what happens.
 
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BCNP4runner

Rank V
Member

Off-Road Ranger I

1,642
Los Alamos, New Mexico, USA
First Name
Jeff
Last Name
K
Member #

20371

Ham Callsign
KI5FGO / WRFH471
You’re the one who keeps bringing up the ground plane.. I keep saying my problem was and is with dissimilar metals.

I also stated that the water leak caused by the dissimilar metals then fallowed my wiring and other things under the roof to cause more issues... also as Mike stated and so does one of those links posted earlier by you, the body doesn’t form the GP, but the lowest metal structure... so again the easiest way to properly set up an antenna on an aluminum bodied vehicle is to isolate the antenna from the body and bond to the frame so that no Galvanic Corrosion occurs...

you’re also misinformed if you think the GP doesn’t in fact have eclectically characteristics. Take a light bulb center conductor and place it on bare metal in the car body and run a jumper wire from its housing to the tip of your antenna... key up the mic and see what happens.
Looks like this might be a common enough issue for the F-150 to support a commercial solution - an aluminum antenna mount bracket for the 3rd brake light on the back of the cab... Would this address the issues and allow the use of both GP & NGP antennas for the original poster?

Larson Electronics - 2019 Ford F-150 Aluminum Body Truck No-Drill Antenna Mounting Bracket - (4) 3/4" Holes - LED 3rd Brake Light Mount
 
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DRAX

Rank I

Enthusiast I

261
Monticello, IL
First Name
Hogan
Last Name
Whittall
Ham Callsign
W9DRX
You’re the one who keeps bringing up the ground plane.. I keep saying my problem was and is with dissimilar metals.
I brought it up in reference to your post about another poster needing to create a ground plane because they have an aluminum F-150 and I was telling you that aluminum makes a fine ground plane.

I also stated that the water leak caused by the dissimilar metals then fallowed my wiring and other things under the roof to cause more issues... also as Mike stated and so does one of those links posted earlier by you, the body doesn’t form the GP, but the lowest metal structure... so again the easiest way to properly set up an antenna on an aluminum bodied vehicle is to isolate the antenna from the body and bond to the frame so that no Galvanic Corrosion occurs...
Gotcha, misunderstood that the leak caused electrical issues. That said, you're still confused about bonding the body to the frame, its purpose, and if it needs to be done. It doesn't need to be done because Ford already did it. The body and frame are (or should be) isolated from each other to prevent galvanic corrosion, by way of the metal being sealed and isolators being used between any metal fasteners and body or frame parts, and the bonding straps are to provide a clean electrical path that doesn't have to find its way through where it's not supposed to, both to help avoid galvanic corrosion as well as prevent/fix ground loops. It doesn't improve the ability of the horizontal body surfaces of the vehicle from acting as a ground plane.

Not sure where you get the idea that the lowest metal structure is what forms the ground plane. That is absolutely not the case. The metal under the antenna is what forms the ground plane. Not the lowest metal, the metal directly under the antenna. This is why the antenna should be mounted in the center of your roof and, if you have a sunroof, positioned to the rear so there is generally an equal amount of metal roof in all directions under the antenna. The roof (and other metallic surfaces. Not parts. Surfaces, specifically the horizontal ones like the hood, bed, or trunk lid) reflects the signal transmitted by the antenna. If your antenna is a 1/4 wave it has to have a ground plane or your SWR will be way off and could end up damaging your radio. You're also still conflating DC and RF ground, they are not the same and improving or changing one isn't how you improve the other. A perfect example of a product for folks that want a no-drill solution for their F-150 is the 3rd brake light antenna mount. You can either slap a mag mount antenna on it or directly mount antennas to it and then the antennas will use the body as the ground plane.

Think about a magnet mount antenna that requires a ground plane. What makes up the ground plane? The piece of metal the magnet is attached to or DIRECTLY above. That could be anything, either a vehicle's roof, a baking sheet, etc. You could just attach radials to the base of the antenna to form a ground plane, but when you have a nice, big metal body for your ground plane they're not necessary.

you’re also misinformed if you think the GP doesn’t in fact have eclectically characteristics. Take a light bulb center conductor and place it on bare metal in the car body and run a jumper wire from its housing to the tip of your antenna... key up the mic and see what happens.
Sure, and RF can "power" a fluorescent bulb without any electrical connection. Nobody ever said RF doesn't have electrical characteristics. I said DC and RF ground are two entirely different things. You keep talking about doing things for DC grounding and galvanic corrosion as if it's going to help create or improve the ground plane. It won't. Because the ground plane has nothing to do with DC/electrical paths within the vehicle or its chassis components.

Also, keep in mind that electrically isolating the antenna/mount from the roof doesn't prevent the roof from acting as a ground plane nor does it necessitate the use of an NGP antenna. The isolation is purely to prevent galvanic corrosion because, again, it's not DC ground that is used to "create" the ground plane.

For the last time, aluminum makes for an excellent ground plane because it is a better conductor than steel. Tell any seasoned amateur or professional radio operator that aluminum doesn't work as a ground plane and you'll either get a funny look or be laughed at.

Every precaution about proper sealing/isolation with the aluminum body has to do with preventing galvanic corrosion and has nothing to do with the ground plane.

In any event, I'm not going to keep repeating myself. If you're still confused or conflating things at this point I don't think there's anything that I can do to fix that because I get the feeling you're simply not reading or grasping what I'm saying. Maybe this video will help?


And again, RF return path doesn't have anything to do with DC/electrical current flow and trying to improve the body to frame ground paths by adding (more) bonding straps is not going to create or improve the ground plane. Saying that people need to add bonding straps to their aluminum F-150 trucks to create a ground plane is simply nonsense because RF ground doesn't give a crap about DC current paths.

Take care and good luck, I'm out of this one.