Ultra Lightweight 2m Yagi Beam Homebrew Plan

[Bug_out_Bag]

This antenna is super lightweight with the elements made from piano wire and the boom made from an arrow shaft. Super lightweight should also read as reasonably fragile. Dependent on the terrain you're moving about in may determine if this is suitable for your requirement. This design taken from Matt, K0MOS, see:


http://www.schnizer.com/SOTAblog/equipme...yagi-sota/

I'm making one of these to use with my Walkie Talkies including the Baofeng UV5R+


   

[Lightspeed]

Good find BoB.

Have you any idea how the elements are attached to the arrow boom?

I'm guessing that the arrow is drilled and the elements passed through it, making a contact fit with the insulation?

There is a very nice commercial version of this antenna called the arrow antenna. It has 2m and 70cm elements arranged at 90 degrees to one another, and a rubber bicycle handlebar handle behind the reflector. Its very effective too.

[Bug_out_Bag]

I forgot to mention that the elements are transported inside the empty hollow of the arrow shaft which makes it really nice and portable. Yes elements pass through drilled holes in boom. You can of course buy the Arrow Antenna! Personally I prefer to make mine and use my hard earned cash on things that can't be quite so easily conjured up.

This antenna is to be tested at altitude locally prior to some SOTA activation and then after November it's main use will be for communicating with ISS, The International Space Station again. 73

[Steve]

I have a few questions, I'm guessing Lightspeed will be answering.

Is this primarily a "line of sight" system, and therefore of little use unless you live on a tall hill or want to talk to a satellite ?

How much is reception improved over the standard "rubber duck" type ?

Where exactly do the wires from the coax have to join the driven element ? How critical is it ? How long should the "un-coaxed" parts of the feeder cable be ?

How much improvement will extra director elements give ? And what is the spacing for them ? Given room for a loooonnnggg version, an accurate alignment method and a hilltop location, what number of elements will give a useful gain before the law of diminishing returns kicks in ?

Does the element support have to be metallic ? The length is specified to 1/10th m/m which suggests it plays an active part, but I don't know how.

How long can the coax between my Baofeng and the Yagi be ?

If I decided to build one for a frequency of my choosing, for a more private link, does anyone have the formulae to calculate the sizes ?

Ta.

[Bug_out_Bag]

Steve wrote:"I have a few questions, I'm guessing Lightspeed will be answering."

You cheeky little fucker! Go swivel!

[Steve]

Sorry BoB, that didn't quite read as it was meant to.

Feel free to answer my questions yourself

[Bug_out_Bag]

No, both replies read as passive agressive Steve.

[Lightspeed]

C'mon BoB. To be fair, I do tend to jump in quick with answers to questions like this.

Its your thread, can you give Steve the benefit of the doubt and answer his Qs?

Cheers LS

[Bug_out_Bag]

Oh dear! I don't think you're hearing me sunshine!

[River Song]

BoB - unless one is well trained, it's difficult to decrypt the language :-)

It's like when my OH, says "Thats a nice dress you're wearing today darling and I respond "What was wrong with the one I was wearing yesterday"

:-)