"John Smith" wrote in message
...

"Richard Clark" wrote in message
...
On Fri, 09 Jan 2004 12:46:24 GMT, "Marvin Rosen"
wrote:

In reference to a previous post concerning
the construction of a center-fed 10 mtr vertical.
Is it posible to construct a 10, 6 & 2 mtr all-in
one center fed vertical using coax as the feed line?

Hi Marvin,

Sure, merely more elaborate, and with elaboration comes the pain of
implementation. By rough math, it could end up as 5 sections at 2M,
and something under 2 sections for 6M - all in terms of quarterwave
length elements.

The trick is in that "partial" second element for 6M - not to speak of
the interactions of tuning to three bands. Perhaps a 5/8ths for 6
instead and a quarter and two halfwaves for 2M. This all depends on
how gracefully the three bands can be made to resonate with the same
fixed sections of wire. Then the question becomes, can you do the
same trick for the lower half (tubing) the line is coming up through
(if you choose that feedline path)? Would it be worth it (simply take
what you got and juggle the tuning in the upper element)?

For the side fed vertical dipole, rummage through the adds or online
designs for a similar horizontal dipole. Turn 90°.

73's
Richard Clark, KB7QHC

In the ARRL Handbook (and probably other ARRL publications), there is
shown
a multiple-band dipole. It consists of half-wave elements all attached to
the same feed line but the dipole for each band is slightly separated from
the others. It is essentially multiple dipoles in parallel.

So, couldn't this work, as you say, just turned vertically?

John
KD5YI


My experience is that several dipoles may share the same feed line, but to
get the least interaction they should fan out at about 15 degrees, but only
for a fraction of the length of the dipole. I used a ring to spread the
elements out to about 6 inched from the centerline, and had five separate
dipoles on a single feed. The first ring was 20 inches from the feed, and
there were additional rings about every five feet.

When you trim the elements you will notice slight effects of increased
capacity, but not a major change.