[TowerTalk] 204BA boom resonance, problem for 40 or not ?

[Marko L Myllymaki]

Hi,

Would anyone have any insight to offer on this or real life experience of
this combination you could share:

I know some of the tribander booms+end elements  such as KT36XA with
non-insulated elements can resonate on 40 meters and so messing up with 40 m
yagi if mounted on same mast nearby.  There was great article of this in NCJ
while back.  KT36XA boom is 32 ft long. 

Does anyone have insight if same issue happens with 204BA with its
non-insulated elements and 26 ft long boom, or does its boom+elements
resonace fall outside of 40 m band ?   Is there someone who has modeled this
?

If tribander boom+end elements resonance actually does fall on 40 m band,
then is this even problem if booms of 40 m and tribander are aligned, or
would it be problem only if antennas are 90 degrees off each others ?  Have
heard various opinions on this and I don't have yet my own experience on
some of these things.

 

I'm considering what combination I will put on one of the 2 towers.  Current
plan is now to have M2 40M3L linear loaded yagi at the bottom of mast, then
maybe around 8 ft above that 204BA and some 15 m yagi another few feet above
20 m.  Booms of 40 and 20 would point same direction and 15 at the top would
be 90 degrees off in order to minimize coupling between 40 and 15 m
antennas.

I have 40M3L already in my possession, but I'm trying to decide what to do
with 20 and 15 on that tower.  There are other possibilities, but above is
what I'm currently considering.

 

Need to decide path to proceed fairly soon, and I'm not planning to start
learning modeling SW right now.

I would very much appreciate any insight and experience on this combination.

73 de Marko N5ZO