Iain Kelly wrote:
Sounds like a scaled up version of an antennas I built from a design
called 'The Mighty Wide 6M Dipole'... The design came from the internet
I think, I seem to recall G0IER published it on his website. I have also
seen the scaling information for other bands...

Thanks, but it led to some questions.

Here is the web page I found for it: http://www.qsl.net/g3pto/6m_dipole.html

From my calculations, assuming his center frequency was 51 mHz, he used
a size factor of 142.494 for the total length of the antenna. This seems
odd to me, as it would translate to 467.5 feet which is number I've
never seen before. Either something is amiss in my calculations, or he
used a different center frequency or just an unusual number.

The shorted length makes perfect sense, the ratio of total to shorted is
..8425 which is a reasonable velocity factor for 300 ohm twinlead.

The length of the stub makes no sense to me at all, but I'm sure he had
his reasons.

Using the proportions he used, I wrote a perl program to calculate the
size for any frequency.

For six meters, it matches his dimensions with a center frequency of 50.1 mHz:

for frequency 50.100 mHz.
total length 9 feet 3 inches or 2.844 meters.
shorted length length 8 feet 10 inches or 2.396 meters.
difference length length 0 feet 8 inches or 0.224 meters.
stub length length 0 feet 11 inches or 0.298 meters.

For 20 meters (14.175 mHz center frequency) I got:
for frequency 14.175 mHz.
total length 32 feet 11 inches or 10.052 meters.
shorted length length 32 feet 9 inches or 8.469 meters.
difference length length 0 feet 7 inches or 0.792 meters.
stub length length 0 feet 5 inches or 1.052 meters.


Anyone have any ideas? Will this work? How do I calculate the stub
length?

The ARRL Handbook antenna (not to be confused with the ARRL Antenna
Handbook, which he used) was slightly different, although this would work too
if my calculations are correct.

Geoff.
--
Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM
IL Voice: (07)-7424-1667 IL Fax: 972-2-648-1443 U.S. Voice: 1-215-821-1838
Visit my 'blog at http://geoffstechno.livejournal.com/