[TowerTalk] 1/4 wave vertical with counterpoise

[David Gilbert]

K9YC said "Takeoff angle is a stupid concept.".

That is hardly true.  Focusing ONLY on the gain at maximum takeoff angle 
may be misleading, but when comparing the same antenna at different 
heights or comparing the same antenna over different ground conditions, 
I don't know of any situation where the difference in angle of maximum 
signal strength doesn't mean there is also a difference (good or bad) at 
every other angle.  In almost every case, if I want to get more gain at 
lower angles I have to work to depress the angle of maximum radiation 
... again, given the same antenna.

Of course it's a totally different situation when comparing different 
antennas.

By the way, in my recent video there were reasons why I didn't bother to 
show all of the plots on the same scale like you keep harping.  For one 
thing, there were so many plots that if I put them all together the 
result would have been gibberish.  Secondly, the shapes of the elevation 
plots and the various signal strengths were so similar in almost all 
cases that ti wasn't necessary ... which was pretty much the point of 
the video in the first place.  Besides, the video was already well over 
20 minutes and getting too long.

Dave   AB7E



On 1/17/2026 3:05 PM, Jim Brown wrote:
> On 1/17/2026 12:56 PM, Brian Beezley wrote:
>> I never worry about takeoff angle, which I take to mean the angle of 
>> the maximum lobe in the elevation plane. Communication takes place at 
>> angles determined by path distance, ionospheric height, ionospheric 
>> tilt, and probably more. It does not necessarily occur where any 
>> particular lobe is located. I generally pick what I think is a 
>> representative low angle, usually 5 degrees, and compare gain for all 
>> antennas I'm considering there.
>
> YES!  Takeoff angle is a stupid concept. For those reading the mail, 
> look at the link I posted about antenna planning, which contains plots 
> of multiple conditions on the same scale, and compare the dB 
> difference between those conditions at the same vertical angle. While 
> propagation takes place at all angles, for the most part, low angles 
> are most important, especially on the lower bands.
>
> All of these plots look similar, so looking only at the field strength 
> at max misses a lot. And both NEC and ARRL plots automatically scale 
> plots to that maximum value. When using NEC for designs, it's helpful 
> to save a plot for one condition, then import it into the screen for 
> variations we make. The cursor on the imported design will read out 
> the difference from the current design. VERY instructive.
>
> Doing this can often point out that curves that look very similar and 
> have little difference in "takeoff angle" can have differences of 3-6 
> dB at low angles! And look at the differences in how the height of HF 
> verticals changes both their vertical pattern and ground loss!
>
> 73, Jim K9YC
>
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