On 9/29/2020 7:51 AM, Jim Thomson wrote:
## Cut the poor guy some slack.
That EFHW ant that Danny Horvat makes is pretty damned good.
Covers 8 bands, 75-40-30-20-17-15-12-10 No tuner required.
Uses 3 big cores. Good for 2 kw icas. Unique design.
https://myantennas.com/wp/product/efhw-7510-2k-plus/
## Joe ham would be doing one heck of a lot of experimenting, and
several renditions, and still not pull this engineering feat off.
Jim VE7RF
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This marketing claim strains credulity. I used to have a
half wave end fed wire cut for 80 meters @ 50 feet. It had no more
bandwidth than a typical 80 meter dipole. I had a matching
network with a tapped coil and a motorized switch to cover
the band in 100 kHz steps. The impedance was around 3,000 ohms,
which is very roughly 50 X 75 ohms. On 40 meters, it functioned
as a full wave end fed. However, the resonant frequency was
above the 40 meter band, and it had to be tuned down using
a switched in capacitor. The drive impedance on 40 was
considerably lower. After much due diligence, I was able
to make a usable 80 and 40 meter antenna. I made my first
clean sweep in SS using it (plus my KT34).
The idea that a simple transformer could cover all the bands
from 75 to 10 meters with no tuner is simply not believable.
I see that there are no specs on SWR, etc. Then there is the
issue of the various patterns on the various bands. No cleverness
at the drive point mitigates this.
Rick N6RK
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