[amsat-bb] Helical Antenna for 2-meters

Michael Fletcher oh2aue at kolumbus.fi
Fri Feb 24 10:21:32 UTC 2017



> I just did some calculations from the ARRL Antenna Handbook.
> I came up with a 6-turn helical with a diameter of 25.826" and
> a length of 121.65".   My first thought was "whoa, dude, like OMG!"
> (I'm a high school teacher, ok?)   I rechecked my calculations and
> came up with same, plus an impedance of 150 ohms.
>
> Years ago I used a Fritzel Helical for 2m when I was DA1BB and VP2EHF
> (during Hurricane Luis in 1994 it ended up someplace out in the
> Anagada Straights between Anguilla and Sombrero Island).
>
> What say, you all?   Advice, comments welcomed
>
> 73
> Dave, N4CVX

Nah Dave,

that's not big, just a scaled down version of e.g. this one (for
~22 MHz, reception of Jovian storms, built by OH8PX, SK):

http://www.rfshamaanit.fi/hf_helix_1.jpg

Your impedance is about right too, but there are several neat ways
of getting this matched to 50 ohms in a fairly broadband manner,
easily googled.

73 Michael OH2AUE


More information about the AMSAT-BB mailing list