[Amps] Vertical Ant & Ground Loss [WAS: MOSFET amp filtering]

[qrv at kd4e.com]

Jim Brown wrote:
> On Mon,12/12/2016 1:55 PM, Catherine James wrote:
>> Jim Brown wrote:
>>> Cathy James wrote:
>>
>> It all depends what you are trying to do.  For solid regional
>> coverage, a low dipole gives excellent NVIS coverage.  For DX, it is
>> less than ideal.
>
> That's an urban myth.  See my tutorial on this.
> http://k9yc.com/VertOrHorizontal-Slides.pdf  A low dipole is much less
> efficient than a high one. Especially study slides 18-22. Then fast
> forward to slides 60-66.
>>> A FAR better choice for something suspended between trees is a Tee
>>> vertical, where a flat top wire provides top loading for the vertical
>>   section, which does the radiation. Because antenna current splits
>> equally left and right into the top wires, radiation from the top
>> cancels, and you end up with a nice vertical radiator and a nice low
>> angle of radiation.
>>
>> That's great for DX, but lousy for regional coverage.  And here in
>> northern New England, our ground conductivity is awful, which makes
>> verticals challenging.  No matter how much you improve the near field
>> with an excellent radial system, the far field will still have lousy
>> conductivity and that will push the radiation angle higher.
>
> Lousy soil does NOT vary the vertical angle, it simply attenuates the
> signal.  In the near field, it burns transmitter power by warming the
> worms. In the far field, it degrades ground wave and weakens the first
> reflection that creates the vertical pattern.