[amsat-bb] Helical Antenna for 2-meters
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
> Dave, N4CVX
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):
Your impedance is about right too, but there are several neat ways
of getting this matched to 50 ohms in a fairly broadband manner,
73 Michael OH2AUE
More information about the AMSAT-BB