[Elecraft] EFHW

[Wes Stewart]

Don,

As I said earlier in this thread, if the radio is on the ground, or near the 
ground, then the antenna is a vertical.  I don't care what the slope is, it has 
a vertical component.  A Beverage is a horizontal wire, but it is vertically 
polarized and works against ground.  It may be lousy ground (which is actually 
required) but nevertheless there is a connection to earth.

I think the fallacy here is that folks believe that a 1/4 wave wire, which 
wouldn't have such an intractable feedpoint impedance, requires "ground" and an 
EFHW doesn't.

Now if the battery-powered radio is dangling above the earth at the end of a 
horizontal wire and the keying is via Bluetooth I guess there is some ground 
independence.  But in that case I would recommend putting the radio in the 
middle of the wire and saving some grief.  Likewise, if you want to fool with a 
Zepp feed why not use center feed?

If maximizing far field strength is of no concern then I recommend a 50 Ohm load 
on the output of the radio :-)  You could crank the power down to save the 
battery and it would have no effect whatsoever on the signal strength at the 
receiving end.  A win-win!

Wes  N7WS

2/12/2017 11:29 AM, Don Wilhelm wrote:
> Wes,
>
> I do not doubt what you are saying about 1/2 wave verticals, but most EFHW 
> antennas are mounted as a sloper or a horizontal antenna.
>
> For portable operation, the main concern is for the ability to feed the 
> antenna, and not about maximizing the far field strength.
>
> 73,
> Don W3FPR
>
> On 2/12/2017 12:34 PM, Wes Stewart wrote:
>> Alas, if only this was true.
>>
>> Google "radial system design and efficiency in hf verticals" and you
>> should get a cached version of Rudy Severns' paper of the same name.  In
>> it he states:
>>
>> "Alternately we can graph efficiency in terms of Ga as shown in figures
>> 3 and 4. Unfortunately this also shows how inefficient verticals are
>> even over very good ground. Very depressing! For example, with very good
>> soil (0.02/30) and 128 1/2-wave radials, the efficiency of a 1/4-wave
>> vertical is still only -2.76 dB (53%)!"
>