Painting an antenna? Bad idea?

I'd ask in a Ham Radio group. Be prepared for a _very_ long thread with your answer maybe buried if you're lucky.

Dave "Learned long ago to be careful asking a Ham for antenna advice" Hinz

If it's a fixed antenna like a J-pole then painting it with something nonconductive would probably help in the long term.

As long as you don't use a conductive paint over insulated portions I don't see any reason why it should affect it except in a positive sense...if it's outdoors, it'll forstall corrosion of the metal parts.

I just noticed GM is back to putting the car radio antennas in the windows again. SWMBO's latest "new to her" '03 Buick has the antenna in the back window, IIRC they were part of the windshield a while back. Haven't studied it to see if they got dual usage out of the defroster heater elements by making the antenna out of that, but rest assured my curious mind will have me doing that before long.

Jeff

Non conductive paints, no. If you're painting it, you might want to make sure you go back after it's up and paint over the terminals too, might make it a pain to disconnect, but would prevent corrosion. Spar varnish works well too.

Stryped

If you want to *discuss* the properties of antennas, there is a wonderful news group named Rec Radio Amatuer Antennas. There are alot of really well informed antenna guys there. My advice would be that you build the antenna from EMT and try it. Isnt thats what HAM is 'all about'??

Jerry (who made his living as an antenna design engineer)

No problem. Krylon, Rustoleum.... paint away.

-Spencer

STRYPED

I just went to the antenna news group to read their 'latest' and see that you already posted questions there. I feel like I just stepped in a "pile"when I see that you ask for antenna advice in RCM *after* discussing it on the ANTENNA group. It becomes obvious to me that you are interested in discussing rather than actually building an antenna. There are world class antenna experts available to answer *any* antenna questions in the Antenna News group. Take their advice.

Jerry

How do you expect the signal to get in or out of the metal antenna if you cover it up with paint?

John W7JDA

Why would conductive paint hurt it? It shouldn't change the wave length. Assume nothing shorted with the paint.

Antennas of the type used on large antenna sites such as building tops and mountian sites are generally gain arrays, vertically oriented and housed in a plastic-like radome. They are several feet tall and only a few inches in diameter. Paint would not be a good idea for obvious reasons on this type of antenna.

Bob (ex-antenna site manager) Swinney

Styped

I see that there are posts on the Antenna Group that reguard you to be a TROLL. Is that true?? Is this antenna questioning on RCM a way for you to have fun with the helpfull guys on RCM?

Jerry

RF current flow is confined primarily to the outer edge of a conductor ("skin effect"). So you can have the highest-conductivity material in the world for the antenna, but if you use conductive paint your RF power will be flowing through -- and being consumed by -- the paint.

So unless the paint has a higher bulk conductivity than the metal, use nonconductive paint.

painting it

I honestly plan to build one. I am going to my first ham event Saturday and hope to pick a radio up. I just ask alot of questions because I want to be educated. Some people get tired of my questions but they are legitimate questions.

Right now I cant decide whther to build a ground plane or j pole and what materials. I would also like to build a scanner antenna for airplane frequencies. But 108 139 mhz is alot of ground to cover. I am not sure one j pole or ground plane would work in that situation.

Please understand just because I ask alot of questions does not make me a troll. I just want to learn and build this the right way.

Thnx Jerry for the poss. Troll Alert. That's all we need: A HAM wanna-be loose on RCM.

Yeah, and what's with the hotmail address?

Jim

Well now, not _every_ person posting from hotmail is a troll.

Dave "It just seems that way..." Hinz

A side note to the viewers...Jerry has forgotten more about antenna design than most of us will ever know. And the military loves his work...they keep sticking them up.

Gunner

"At the core of liberalism is the spoiled child - miserable, as all spoiled children are, unsatisfied, demanding, ill-disciplined, despotic and useless. Liberalism is a philosphy of sniveling brats." -- P.J. O'Rourke

Metal content to follow under the discone topic (I had to reach to get it in there ;-))

Ground plane first. Just get something working to start with.

J poles are a blast but a bit 'fiddley' as a first antenna in my opinion. That's what makes them a kick to play with.

Do your scanner as a separate antenna for now. (just get something working). A home brewed discone might be fun. but for now, how about another ground plane? A look at a discone will give you any number of ideas on how to get the ground plane elements at the right angle. An indexing jig on an angle table in the drill press would make a nice looking start.

I'm doing a bad thing and not getting involved in the rest of the discussion, but what you need is an antenna you can listen with while you're building the ultimate loaded happy hoohaa bedspring grounded gopher catcher. At least that way you have something to listen to, and compare the results of each of the new antennas with.

When you get your ticket, inverted V if you're on HF, and a ground plane for vhf. You'll find you end up hanging out on mostly the same area of a band, just tune them up, get em running, and build the ultimate wave catcher next weekend. in the mean time, you'll have something that you can listen to.

Humm,,, I guess from my stand point, just get something in the air, even if it's just a long wire into the trees. It's a lot easier to work on an antenna, or other project (even in the lathe) if you've a good receiver running in the back ground.

Now for all the other guys,,, just get something up for now, then as soon as you get your super special rig running you can always take the ratty old thing down.

Did I say just get something working? Good luck, have fun, and it's a hobby,,, it's supposed to be fun!