Daniel,
I agree with Gary - building and tuning a quad properly is a lot of work,
and perhaps it is better to start with a smaller, 2 element quad and improve
it later?
My antenna is made by Gem
www.gemquad.com , which is a boomless design that
offers optimal spacing on all bands. If you are good at welding and can
build the center spider support, the rest of the antenna is easier. My
antenna began as a 3 band (10, 15, 20) model, then added loops for the 12
and 17 meter WARC bands. Then I added a 2 element 30 meter "U" shaped dipole
beam between the 20 and 17 meter loops. Then I added a D.E. and reflector
for 6 meters. So, although it is only a 2 element quad, is it is now a 7
band antenna!
I use a remote antenna selector switch on the mast of my quad, and select
the bands in 4 groups: 20 meters alone, 30 meters alone, 17 and 15 tied
together, 12 and 10 meters tied together, and 6 meters. Because the base
impedance of a loop calculates at 105 ohms, I use a 1/4 wavelength 75 ohm
feedline in each group of wires to bring the SWR to 1:1 for each band. (The
15/17 group feedline is cut for 15 meters; the 10/12 meter group feedline is
cut for 10 meters. SWR is still excellent on the 17 & 12 meter bands.)
My quad has been in the air for 9 years and gives me very good performance,
but I must tell you that an antenna with this much wire at 70 feet requires
a LOT of maintenance. This quad is mounted on a tilt-over tower which makes
fixing the antenna easier -- I can drop the tower with a motorized winch and
work on the antenna from the ground. I would not recommend that anyone
install a quad on a stationary tower that requires adjusting/repairing at
the top of the tower.
I hope you find my information helpful. Please feel free to email for more
information.
--
-larry
K8UT
"Daniel Ferrato - IK2SGL" wrote in message
...
Since I haven't gotten any reply I'm trying again.
Thnak you in advance
Daniel
IK2SGL
"Daniel Ferrato - IK2SGL" ha scritto nel messaggio
news:...
Dear OM, I would like to build a Cubical Quad multiband and I've found
the site of EI7BA
http://www.iol.ie/~bravo/Cubical%20Quad.htm, I'd be interested in
building up something like that but with 3el. I was thinking about having
the director and reflector opened at pyramid-shape like the EI7BA project
but the radiator at normal crossing like the fixed spacing in the common
multiband version.
Do you have any projects or tips? I'm a newbe in building antennas.
73s
Daniel
IK2SGL
Como - JN45MT
volevo chiedere se esisteva
qualcosa di simile perņ a 3 elementi. Pensavo a qualcosa del genere
riflettore e diretttore posti ad apertura conica e direttore a croce
normale.
Sapete illuminarmi su eventualli progetti?
Salutoni
Daniel
IK2SGL