[Elecraft] EH antenna??

Sat Feb 22 23:21:00 2003

Thanks. A couple of people pointed that an "EH" antenna is "small". From
the reference document that I read, I saw NOTHING about it being
especially small. 

To quote the text about size, it says: 

"What is the minimum size EH Antenna? It is determined by the allowable
inefficiency for the intended use, which
is dictated by the amount of antenna capacity resulting in the necessary
external tuning inductance with its
associated loss. As seen above, a very small EH antenna has no
measurable loss in the conductors, thus the total loss
is in the phasing matching network." 
(http://www.eh-antenna.com/documents/EH_ANTENNA_DEFINITION.pdf)

That fits conventional antenna theory as I know it. A 3 foot doublet for
80 meters exhibits very little ohmic losses. After all, how much
resistance does 3 feet of, say, copper pipe have? (And it's much higher
than the resistance shown by an ohmmeter, because r-f only flows in the
very skin of the conductor, but it's still not much).

However, as we all know, the losses in the matching network are
tremendous, especially compared with the radiation resistance of the
antenna. And since the ohmic resistance of the GIGANTIC inductor
required to shift the phase (tune) the antenna is going to be far, far
greater than the radiation resistance, the efficiency will be very, very
low. That's exactly why an 80 meter mobile whip doesn't get out as good
as a full size antenna! 

Any Ham licensed since Marconi was stringing wires knows that. 

Like I said before, they keep saying exactly what I find in ANY antenna
book, although the context seems to suggest that it's a "new" discovery.

Oh, well, as someone else mentioned off the reflector, watch for
production units at big prices for the gullible. 

Ron AC7AC
K2 # 1289

-----Original Message-----
Think "Point Source"

I've loaded up on cuff links, coat hangers, window frames, bed springs,
etc.

IMHO - Basic maxim still holds true --- Bigger and Higher is Better and
Louder

Dave KK7SS,
K2 #3003

> It appears that they will work VERY well. Just as well as
the antennas
> we've been using for years, in fact.
>
> That's the problem. The more I study them the more they look
exactly
> like the antennas I already know about...
>
> The difference seems to be in the terminology used.
>

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