[TowerTalk] interaction problem...

[David Gilbert]

Hi, Gary.

OK ... I think I understand better now.  If the F/B of the stack is that 
low, then something must indeed be amiss, and having the SWR vary that 
much as you turn it would probably concern me as well.  It's going to 
take one of the experts on the list to comment on that.

HFTA shows, however, that below about 12 degrees takeoff angle (which 
covers most 10m DX) the stack will only give you about 10-12 db gain 
over the dipole.  Between 12 degrees and 20 degrees, the stack has a dep 
notch and the dipole would, according to HFTA, have a significant 
advantage ... maybe even a few S-units.  The stack doesn't show a gain 
greater than 12db over the dipole until you get way out to about 21 
degrees where the dipole has a notch, and that angle is pretty high for 
most 10m propagation.

73,
Dave  AB7E


StellarCAT wrote:
> David,
>
> Thanks for running this.... however what I am seeing is, much 
> more often than not, the dipole is only about 8 db below the 
> array - and at times almost equal ... this is not quite within 
> your run - I would assume the array would be on average ~12 db 
> greater and at times even more so! I have only seen it more than 
> this once. In addition the FB is about 8 db and the antenna 
> shows almost no variation as I rotate it around. There is no 
> forward peak to speak of (I actually saw it peak just off of 
> forward when looking at one station that was ~20 degrees angled 
> to a guy - it peaked with the antenna looking OVER the guy!). 
> Its this latter fact that bothers me (as well) - no real 
> directivity to speak of.
>
> And the SWR varies from 1.3:1 to about 2:1 depending on where 
> the antenna is relative to the guys.
>
> g.