I would be interested in 40 M and up and I
have and use a Johnson KW MatchBox. I
believe that would help tune this antenna.
Gary
On 8/25/2015 12:36, Scott Royall via BVARC wrote:
I might be interested, depending on physical dimensions.
*From:*BVARC [mailto:[email protected]] *On Behalf Of *Bill
Crowell via BVARC
*Sent:* Tuesday, August 25, 2015 10:51
*To:* Bill Crowell via BVARC <[email protected]>
*Cc:* Bill Crowell <[email protected]>
*Subject:* [BVARC] TTFD Antennas - N4HPG
Howdy All,
I was listening to the net last night and John, K5IZO, was encouraging
folks to get on 75m. Yay!
I’ve been working on a project for a number of months. Some of you
know that I use a TTFD antenna. TTFD or T2FD. It stands for Tilted
Terminated Folded Dipole. This antenna is not widely known because
it’s not featured in any ARRL publications – at least since 1949.
There are some good reference sources such as the RSGB wire antenna
book. There are also some detractors that don’t understand the theory
of operation.
Here’s a link to the original article:
http://www.scribd.com/doc/42625655/An-Experimental-All-Band-Nondirectional-Transmitting-Antenna-T2FD
You’ll notice that the antenna is a 600-ohm design. It is a balanced
antenna.
Perhaps Rick Hiller and I should give a presentation on it.
I’ve been using the B&W version for a number of years, but want to
run higher power. That means a better matching transformer for 50:600
ohms and also a more robust terminating resistor. The antenna works
well from 75 to 10m with 1.5:1 SWR or better on all bands. This is
because it’s a traveling wave antenna. Mismatch is soaked up by the
terminating resistor. No tuner is needed. The antenna works from the
lowest frequency up. That means a 80m antenna works on all bands from
80-10m. A shorter antenna works from 40-10m. B&W says 6m, but I’ve not
tested my high-power balun for 6m yet. I never promise what I haven’t
tested.
I’m hoping to bring a completed unit of the high-power design to the
club meeting on 9/10 so y’all can look at it. I should probably fire
up N4HPG.com website and post some pictures.
_If you can have only 1 antenna, this is the one to have. I like to
hunt DX and change bands without having to tune. Get as long an
antenna as possible!_
------------------------------------------------------------------------
The folks at B&W now want $825 for their version. That’s insane! But
they sell mostly to military and governments.
I’m making one antenna for myself that will be all my build. I’m also
making a heavy-duty one for N5XZ. Being gainfully unemployed and
having a workshop, I’m testing the waters to see if others might want one.
When we put up an antenna, the neighbors usually notice. I’m making my
version with 14awg white MTW wire and clear, acrylic spacers for the
antenna and the ladder line. The balun box mounts on the wall and
transforms the 50 ohm unbalanced to 600 ohm balanced. It’s a 6x6x4 box
because there are 4 toroids.
Based upon present materials, I believe I can produce the standard
antenna – 1kW for normal operation for $349. I’m still working on the
N5XZ 1.5kW RTTY Contesting version that will be a bit more.
If you want to build your own, feel free to steal my design!
For those who would like a built and tested unit, let me know. I’m
trying to decide if I should get into the antenna business.
73!
N4HPG
Bill Crowell
Pearland, TX
_______________________________________________
BVARC mailing list
[email protected]
http://mail.bvarc.org/mailman/listinfo/bvarc_bvarc.org
_______________________________________________
BVARC mailing list
[email protected]
http://mail.bvarc.org/mailman/listinfo/bvarc_bvarc.org
