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