Need info for antenna build

[Broke Spoke]

I have a few questions for a project antenna build. First, I'm going to build a two element beam using 13 ga. wire on a pvc frame. When using wire, is it necessary to remove the shielding from the whole wire? If so, would a clear enamel be a good choice to coat the wire for protection? I will also use a balun for the feed point. Is the balun calculated as part of the wire length to keep the correct frequency? Last question, how is the swrs adjusted when using a balun? Any info will be greatly appreciated. Thanks.

 

[binrat]

I have a few questions for a project antenna build. First, I'm going to build a two element beam using 13 ga. wire on a pvc frame. When using wire, is it necessary to remove the shielding from the whole wire? No, I would recommend keeping it on as much as possible.
If so, would a clear enamel be a good choice to coat the wire for protection? I will also use a balun for the feed point. Is the balun calculated as part of the wire length to keep the correct frequency?No Last question, how is the swrs adjusted when using a balun?ry adjusting the wire length first Any info will be greatly appreciated. Thanks.

If you plan to use a balun always try and get the lowest swr by adjusting the length of the wire.

 

[Captain Kilowatt]

Binrat has all the answers on this one and I agree with all of them.

 

[Broke Spoke]

Thanks guys. Once I get the material for the build, I will post pictures and keep you updated.

 

[binrat]

Remember to start with the wires too long and fold back along itself as need. Makes life easier if by chance they are too short to start. Don't get frustrated and have fun with it.

 

[Watergate]

Ok, Binrat. Help me understand this then. I'm looking at building a 4 element quad as my first homebrew beam. I found this site with the plans.

http://signalengineering.com/ultimate/4_element_quad.html

To save you the trouble of reading the whole page, this is the part I have a question about as it references your reply to the OP.

" If you are wondering. why can't I keep the insulating jacket on the wire, instead of getting bare wire...won't that protect it better? Yes it will but the wire will be heavy and you really do not want that, it will sag too much. Also, if you do use wire with insulation (don't!) the element lengths calculated above will not be valid, you will need to re-adjust the formulas I used to take into account the insulation on the wire."

So if I were to peel apart some 2/10 romex I have here and use the 10 gauge wire from it, would leaving the insulation on the wire really have that much of an effect on the element length?

 

[binrat]

Watergate,
My reference to the Op about longer wire was regarding tuning it. I took it as he was going to build a yagi style antenna with wire supported. Simply folding the ends back on itself makes life easy for tuning.
From my experience when you use a wire with the insulation on its slightly longer in length for the freq. The author of that site calculated for bare wire so that is what he recommends. If it was me, I would build a loop antenna first and adjust it to the freq that you want, then compare the actual length to his calculator calculated length. He does state that insulated wire is heavier than bare wire with lacquer on it .

 

[Watergate]

Ok. Thanks. Not to hijack the OP's thread here, but one more quick question. If you were to build the quad shown on that site, would you leave the insulation on the wire, or would the lacquer be a better way to go, protection wise?

 

[binrat]

Ok. Thanks. Not to hijack the OP's thread here, but one more quick question. If you were to build the quad shown on that site, would you leave the insulation on the wire, or would the lacquer be a better way to go, protection wise?

Personally if I had wire with it on and there is no breaks in the insulation, I would use it. I'm thinking its a long process to strip it all off. If its old wire then knowing me, I would strip it off and once done lacquer it up real good. I have a few miles of 14 guage fencing wire here so I would use it and lacquer it once done. For me, with antennas, have the fun is to make as cheap as possible.

 

[IRock817]

I'm building a four element in two weeks and using 14 gauge galvanised stranded from the hardware store!! Works well and lasts a long time in the Oklahoma wind! Copper has a tendency to brake from all the flexing and ice.
Take pics!
Have fun

P.S. You should pre stretch your copper wire or it will end up longer and saggy!!

 

[Broke Spoke]

I will actually be building a moxon beam. Once I test it on the air, I will probably modify it to be a dual polarity antenna. Basically two beams on one boom. I posted earlier that I was using a balun at the feed point. I'm curious if a direct feed would be a better way to go. Any suggestions?