"Elegant" Antenna DIY Design Questions - HF/VHF/UHF

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kingshootr

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As I'm planning out the weekend to finish this project up (yeah, I'm a bit OCD) I had another question:

Does putting a steel plate under this kind of antenna do anything positive (or negative) for me?

I'm talking a 16" steel pizza pan like this:

81CuPdgp-yL._AC_SL1500_.jpg
 

mmckenna

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Yes, it's called a ground plane.

You want it to be 1/4 wavelength radius at the lowest operating frequency. Since this antenna covers the VHF band, you want an 18" radius ground plane under the antenna, sort of like if it was sitting on top of a car roof. If you don't have something that big, no worries, something is better than nothing.

You could do the same thing with some brazing rod. 18" long sticking out from under the magnet mount. 3-4 of them would be fine.
 

kingshootr

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No brazing rod, but a ton of steel TIG ones! Just clarifying - is it 18" out from the center of the mount for each rod, or 9"?

Thank you!
 

prcguy

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I would go with your second choice. Why? Because your utility meter and the ground rod appear to be very close by. You need to ground the antenna, mast and coax (via a lightning protector) to that common ground point. It is your best option to have an effective ground, reduced electrical noise induced into your system. There are many discussions about grounding and bonding on RR if you have more questions, you can look at what has been suggested. One important point, when adding your ground wire #12 or larger to the existing rod, use a clamp to add your wire to the rod or a clamp to add your wire to the existing bare solid ground from the meter can. Never disconnect the ground rod or wire from your meter can, even temporarily.
NEC requires minimum 10ga copper or 8ga aluminum or 17ga copper clad steel for the antenna grounding conductor.
 

prcguy

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True. Please tell Dish Network installers!
DirecTV and Dish installers must go through training and they are taught to use green 10ga copper wire for grounding. Many are or were certified by the SBCA (Satellite Broadcasting and Communications Association) and I was an SBCA certified trainer for instructors at one time. If anyone finds a Dish or DirecTV installation that does not comply with NEC you should contact the installation group and complain, demanding it be brought to NEC standards. I've had to do that many times.

Anyone installing their own antenna should also consider code requirements.
 

MUTNAV

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NEC requires minimum 10ga copper or 8ga aluminum or 17ga copper clad steel for the antenna grounding conductor.
17 gauge copper clad steel seems kind of thin, doesn't it?

Thanks
Joel
 

prcguy

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And another thing... 10ga copper or 6ga aluminum or whatever meets code does not mean it will survive a direct lightning hit. The NEC compliant wire sizes are for human safety grounding so it puts a particular leg of the ground system at a similar enough potential to the main ground so that it will not create a shock hazard. And that has nothing to do with lightning hitting your antenna and your electrical system surviving. That is a completely different topic that will get real complicated and expensive if you choose that path.
 

kingshootr

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Radials installed, ground wire secured, and a couple coats of shiny paint. Tomorrow morning I'll get it up and see if it's any good.

Compress_20230707_181245_5292.jpg

Compress_20230707_193239_9110.jpg
 

kingshootr

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What?

7beb899f6bfc3dde9afbc3d419735626c310d07751cdc94fc36f10305e30e877_1.jpg

Better safe than sorry. You never know when I might stick a 20ft extension on there for a little more reach :cool:.

And any excuse to fire up the tools.
 

prcguy

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What?

View attachment 145051

Better safe than sorry. You never know when I might stick a 20ft extension on there for a little more reach :cool:.

And any excuse to fire up the tools.
Someone should have had an intervention early on in this thread. I would have ditched the mag mount and gone with a Discone or anything else. All you would have needed was the mast and in the end you could have enjoyed better performance.
 

kingshootr

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Haha, probably. I have many faults - cheapskate, OCD, yada yada. I'm getting back into scanning after 20 years - and I already have too many hobbies.

This setup is to see if I'll enjoy it as much as I hope. Can't see throwing a bunch of $$$ on a whim.

If things work out well after this setup (I mean, all I'm getting now is FM, the weather, and a DPS call once in a while) then the mast is well suited for an upgraded antenna.

For $100, I'm cool with where I'm at.

Maybe I can mount an antenna on my totem pole...

Compress_20230707_213152_2755.jpg
 

prcguy

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Haha, probably. I have many faults - cheapskate, OCD, yada yada. I'm getting back into scanning after 20 years - and I already have too many hobbies.

This setup is to see if I'll enjoy it as much as I hope. Can't see throwing a bunch of $$$ on a whim.

If things work out well after this setup (I mean, all I'm getting now is FM, the weather, and a DPS call once in a while) then the mast is well suited for an upgraded antenna.

For $100, I'm cool with where I'm at.

Maybe I can mount an antenna on my totem pole...

View attachment 145053
Wow, hook some coax up to that thing, then rotate the wings for best reception!
 

MUTNAV

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It does but it satisfies NEC.
The reason I'm questioning the 17 guage copper clad steel is that it is probably a poorer conductor than 12 or 14 gauge copper wire, which is a lot cheaper and more available...

Actually I'm having a hard time finding the appropriate section of the code online (any help would be appreciated).

Thanks
Joel
 
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prcguy

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The reason I'm questioning the 17 guage copper clad steel is that it is probably a poorer conductor than 12 or 14 gauge copper wire, which is a lot cheaper and more available...

Actually I'm having a hard time finding the appropriate section of the code online (any help would be appreciated).

Thanks
Joel
The part of NEC that deals with antenna grounding is Article 810. 17ga copper clad steel is a much worse conductor than the other choices but I think its only used as a messenger wire that is molded into various coax cables and its steel for strength to hold up aerial runs of coax. There is no reason to go out of your way to find it, just use 10ga copper.
 
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