Friday, March 05, 2010

DIY helical antenna for 2m

A few weeks ago I made a rubber duck helical antenna for my TH-F7E. I didn't get around to writing about it at the time, plus it took a while to get some reports of its performance.

Well, it works extremely well, and I have just added a description of how to make it to the main G4ILO's Shack website. See A DIY Ducky for 2m.

2 comments:

Steve GW7AAV said...

Nice description of how to make a helical for 2m. Fits in well with the letter I had published in RADCOM about how you can improve performance of hand held radios by tuning the supplied aerials or making your own. It is available on CQHQ here…
http://www.cqhq.co.uk/2009/05/peking-ducks.html
Maybe you could have included how you worked out how much wire to use so others can maybe do the same thing for other bands.
When I made mine (many years ago) I wound the wire around some threaded bar to get a nice neat coil. I have used the inner insulator from coaxial cable as a former but found hard nylon airline was better as it slid nice and tightly over BNC plugs that were designed to be crimped.

g4ilo said...

Thanks Steve. Good point about the length. Actually I just didn't want my lack of technical erudition to be too obvious. Doubtless there is an impressive looking formula for it. But what actually happened was I came across a post on QRZ that said you need about 5/8 wavelength of wire, so I measured off just a tad on the long side of that and to my amazement (considering the way things usually work out at G4ILO) it worked!