[TowerTalk] Takeoff angle

StellarCAT rxdesign at ssvecnet.com
Mon Jul 24 08:58:23 EDT 2017


There it is - sorry ... no that was my post, Gary ....

sorry for the confusion ... no what I was saying is that the top antenna 
ALONE is never (almost) better than BIP (or all in phase). The difference in 
angle between the TOP and BIP, for me 7° and 8°, generally is very small and 
the gain from the stack, if I remember from the model about 2.4db or so with 
a 2 stack, surpasses the very small increment one gets from having only the 
top antenna in play.

So we're in essence in agreement, I think, all in phase is the best option 
... my point regarding the comment "top is never (rarely?) best" was if one 
were to make a selection switch for fast switching for comparisons - if you 
left off TOP ONLY as a selection, you'd not lose a single thing. That was 
all I meant by that. So indeed BIP (again for my 2 stack) is by far the 
favored selection on 20 meters and so far on testing, limited as its been 
since the tower only went up in late October of last year (2016) I've not 
seen a case where TOP is better than BIP. I do look for it still on LP 

Now that stated I'd say this really is for a 2 stack ... with a 3 stack you 
see more of a difference between 3IP and TOP... and with a 4 stack as well 
... so although with a 4 stack you might have just over 4 db gain with all 
in phase you'd have a AOR that was measurably lower with the top antenna 
alone. So as stated before YMMV...

but to my main and original point - if one is going to stack antenna, 
especially a 2 stack, I'd recommend going with a box that allows BOP. From 
modeling, from HFTA and from 'real world results' it has been a plus for me 
in this limited time (~9 months) I've had the system up.


-----Original Message----- 
From: Bob Shohet, KQ2M
Sent: Monday, July 24, 2017 8:31 AM
To: Steve Maki
Cc: towertalk at contesting.com
Subject: Re: [TowerTalk] Takeoff angle

It is clear – my post was in response to Jim’s post (which was attached) 
where he specifies TOP (antenna) was rarely best and “the lower the better”.

Bob  KQ2M

From: Steve Maki
Sent: Sunday, July 23, 2017 9:27 PM
Cc: towertalk at contesting.com
Subject: Re: [TowerTalk] Takeoff angle

Err, we better keep straight whether we're speaking of heights above
ground or takeoff angle.

-Steve K8LX

On 7/23/2017 20:59 PM, Bob Shohet, KQ2M wrote:

> Gary,
> The lower the better?  Rare when higher is better?  Seriously?

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