David,
the capacity hat does cancel some radiation. Think of RF current going up
the mast and down the top hat wires. The magnetic fields partially cancel.
Without the capacity hat wires the 55' mast exhibits a radiation resistance
of ~5 ohms. With the capacity hat it is also ~5 ohms. So,
On 12/5/2020 5:37 AM, David Aslin G3WGN wrote:
I note that the capacity hat extends to a significant distance down the
vertical section. It's my understanding that will shield some of the radiation
from the upper part of the vertical.
Yes and no. The sloping hat reduces the effective height,
I refined the DX Engineering Thunderbolt EZNEC model to be exactly like the
actual antennat by changing the capacity hat wire size.
It is resonant at 1930kHz. 2.15uH of series inductance tunes it to 1820kHz
where the input impedance is 4.8 ohms. GND + coil loss of 3.2 ohms gives
the claimed DX
I have one of the DXE 80m verticals and it is great. The ability to
crank up and down is nice, although I have never taken it down since I
put it up. The thing is a tank!
I have an inverted L for 160 so I never considered using it on 160.
W0MU
On 12/5/2020 11:26 AM, MU 4CX250B wrote:
Hi
Hi David,
I live in a windy area with 100km frequent wind gusts in the spring. I
bought a DXE heavy duty 80m self-supporting tilt-over vertical on the
advice of a professional tower guy. It was expensive and the assembly took
a couple of days, but the result was worth it. It seemed built to
The DX Engineering Thunderbolt antenna includes a means to resonate and
match the antenna using a series inductor and a shunt inductor. *It does
not require a balun*.
See the manual:
https://static.dxengineering.com/global/images/instructions/dxe-160va-1_jj.pdf
An EZNEC model shows it to be
Or reduce the loading to present a capacitive reactance at the feedpoint and
shunt it with an inductor. Functions as a step up L-network and presents a
ground at DC. That's what I do here.
Wes N7WS
On 12/5/2020 7:35 AM, Rudy Bakalov via Topband wrote:
P.S. If your vertical has a good
P.S. If your vertical has a good set of radials, you will see about 35 Ohm
feedpoint impedance. You may want to wind your own unun using Jerry Sevick’s
cookbook
http://www.introni.it/pdf/Amidon%20-%20Transmission%20Line%20Transformers%20Handbook.pdf
or buy a readymade 35 to 50 Ohm unun from
David,
Are you thinking of buying from DXE and importing? If yes, you may as well
consider buying the aluminum from them and build the vertical exactly the way
you want it. This is what we did at HQ9X for the 160, 80, and 40 meter
verticals.
Rudy N2WQ
Sent using a tiny keyboard. Please
: Topband: Looking for user experience: DXEngineering Thunderbolt
160m vertical
I'm building a contest station and the time has come to make a choice of
160m TX antenna. Looking at DXE Thunderbolt I note that the capacity hat
extends to a significant distance down the vertical section. It's my
I'm building a contest station and the time has come to make a choice of 160m
TX antenna. Looking at DXE Thunderbolt I note that the capacity hat extends to
a significant distance down the vertical section. It's my understanding that
will shield some of the radiation from the upper part of the
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