80/40/30M dipole?
 

Hi guys.
Quick question. I have in the past made 80 and 40 meter multiband dipoles
using parallel wires and they worked fine with little 80/40 interaction. My
question is, can a make one with a set of wires on it for 30M also? or will
the 40M and 30M parallel wires interact too much?

Mark W4UDX

"W4UDX" wrote in message . ..
Hi guys.
Quick question. I have in the past made 80 and 40 meter multiband dipoles
using parallel wires and they worked fine with little 80/40 interaction. My
question is, can a make one with a set of wires on it for 30M also? or will
the 40M and 30M parallel wires interact too much?

Mark W4UDX

Hi Mark,
probably it's possible, see
http://w1.859.telia.com/~u85920178/antennas/dipole.htm I personally
haven't tried it, though.

73 Ivan OK1SIP

Mark,

I had 40, 17, and 12 meters all off the same feedline, and it worked great
(SWR 1.5). Trim the antennas from lowest to highest frequency.

I had the 17 on top as a V (17 was the main support), the 12 underneath that
as a flat top, and the 40 as an inverted V about 30 degrees out of plane
with the others.

Tam/WB2TT
"W4UDX" wrote in message
...
Hi guys.
Quick question. I have in the past made 80 and 40 meter multiband dipoles
using parallel wires and they worked fine with little 80/40 interaction.
My
question is, can a make one with a set of wires on it for 30M also? or
will
the 40M and 30M parallel wires interact too much?

Mark W4UDX

For some reason you never see 30m dipoles in parallel with the rest. I
always suspected there must be a reason. Wonder what impedance 7 mhz would
see on a 10.1 mhz dipole?

--
Steve Ellington N4LQ.
"W4UDX" wrote in message
...
Hi guys.
Quick question. I have in the past made 80 and 40 meter multiband dipoles
using parallel wires and they worked fine with little 80/40 interaction.
My
question is, can a make one with a set of wires on it for 30M also? or
will
the 40M and 30M parallel wires interact too much?

Mark W4UDX

On Fri, 26 Sep 2003 23:01:19 -0400, "N4LQ" wrote:

For some reason you never see 30m dipoles in parallel with the rest. I
always suspected there must be a reason. Wonder what impedance 7 mhz would
see on a 10.1 mhz dipole?

The reason why is that 3.5 Mhz and 10.1 interact somewhat the 3rd
harmonic of 3.5 is 10.5 close enough to give tuning problems. at
least that is what i've found here.. you can minimize the interaction
by placing the 10.1 mhz element at Right angles to the 3.5 mhz
element.. and it may take careful tuning of both bands to get it
acceptible.

73 Dave Kc1di

Sure you can. You can make a 80/40 dipole that is the same length as the 40
meter. THis is the basis for the old Mor-Gain dipole. You wrap the 80
meter wire around the 40 meter dipole
almost like a folded dipole that is open at the bottom. Just like Mor-gain
you can add other bands as parallel wires. There is little interaction.
Jim West of Antennas West built a version called the PM Dipole and found the
40 meter lower band portion was broadened ...I have one Mor-Gain and one
homebrew and find the 80 meter is at least 100Khz and the 40 is less than
1.2 across the band. K4TWJ had a more recent version in his column last
fall using ladder line.
I plan to add 60 meters to one of my dual banders.
73 Dave K4JRB

W4UDX wrote in message
...
Hi guys.
Quick question. I have in the past made 80 and 40 meter multiband dipoles
using parallel wires and they worked fine with little 80/40 interaction.
My
question is, can a make one with a set of wires on it for 30M also? or
will
the 40M and 30M parallel wires interact too much?

Mark W4UDX