[TowerTalk] m2 40M4LLDD + 20m add on

[Jim Thomson]

Date: Tue, 9 Jul 2013 08:26:48 -0700
From: "Jim Thomson" <jim.thom at telus.net>
To: <towertalk at 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