Date: Tue, 9 Jul 2013 08:26:48 -0700
From: "Jim Thomson" <jim.thom@telus.net>
To: <towertalk@contesting.com>
Subject: [TowerTalk] m2 40M4LLDD + 20m add on
I see that m2 offers a optional 4 els for 20m to add onto their 40M boom.
This is for their 40m4llDD yagi..which is their 4 el 40m yagi, with dual
DE..and on
a 42? boom.
Is this option something new ? All as I?m interested in is 14.1 to 14.30
Does anybody have one of these..or heard about them ? 40 +20 on one boom
would be the ideal ticket.
Jim VE7RF
## OK, this is where I saw the info.
http://www.m2inc.com/index.php?ax=amateur&pg=50
Scroll right to the bottom. “Options include parts to add 4 elements for 17 or
20 meters. Call for details.”
Now the above is only listed for the regular version..and is not shown under
the 125 mph version. If
available, it should also work on the 125 mph version....which just has an
internal center re-enforced boom
plus triple walled eles.
## dunno why M2 has not come out with more duoband yagi’s before this. Sure,
the assy ends up heavier,
but it’s a trade off. Only one boom to mess with, instead of two booms.
F12 makes this superb 17-15m yagi array
called a N1715XL. 9 els on a 36 foot boom. 2 els on 17..and 7 on 15m. Direct
50 ohm feed, no hairpin. The
4 x 15m directors look like quasi directors on 17m. 6dbd on 17M..with only 2
els.
They never did make a similar 12-10m combo, which actually would be even easier
to implement.
## A 40-20 combo on one boom has merit. Mounted just above the top of a
tower, it frees up the
entire mast above the tower for more ants.... like perhaps a 80m rotary dipole
or 17-15 array..or
a 17-10m array, etc. Point here is, space on a mast is limited. Ditto with
a rotating tower.
## Opti beam has figured this one out a long time ago. I see on the optibeam
4el 40m yagi, which also
uses dual de, that they also use decoupling stubs as well,,,, so their 40m
yagi will not resonate and screw up
a 20-10m yagi in close proximity. Optibeam also makes a 40/20 combo as peter
noted, but it’s a big mother,
49 foot boom, heavy, big windload...and very expensive. It only covers 200 khz
of the band. You would have
to compare any 40/20 combo to 2 x separate yagis, to see if $$ or weight is
saved.
## Flash... apparently m2 is now making a COIL version of their 40M4LLDD.
The coils are slick, machined
from thick wall AL tubing. The ends of the tubing are not machined in the
lathe. That allows for a superb
electrical + mech connection at each end of the coil. Plus the uh of each
coil is consistent. The LL tubing
was also the truss for each ele, so presumably dacron rope etc, would have to
be used with any coil version.
Later....... Jim VE7RF
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