J. McLaughlin wrote:
After investigating a large set of traveling wave antennas (not
Beverage) I think that the smallest amount of power dissipated in the
terminating resistance was about 2 db. Mind, these were antennas with
useful lengths and angles. It is likely that a rhombic with very long
leg lengths would dissipate even less in its termination resistance.

Well, remember the posting that kicked off this discussion was about
the following very short traveling-wave antenna:

"It is a military inverted-V, 110 ft. long total, with each end
terminated in a 150 ohm resistor driven into the ground, center fed
through a 9:1 balun."

A 110 ft. center-fed inverted-V is certainly going to have extensive
losses in the resistors on most HF bands. After all, it is less than
1/2WL long on 75m and only 3 wavelengths long on 10m.
--
73, Cecil, W5DXP



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Dear Cecil: Your point is well taken.
I was talking about multiple wavelength structures. I should have
noted additional restrictions.

73 Mac N8TT

--
J. Mc Laughlin - Michigan USA
Home:

"Cecil Moore" wrote in message
...
J. McLaughlin wrote:
After investigating a large set of traveling wave antennas (not
Beverage) I think that the smallest amount of power dissipated in
the
terminating resistance was about 2 db. Mind, these were antennas
with
useful lengths and angles. It is likely that a rhombic with very
long
leg lengths would dissipate even less in its termination resistance.

Well, remember the posting that kicked off this discussion was about
the following very short traveling-wave antenna:

"It is a military inverted-V, 110 ft. long total, with each end
terminated in a 150 ohm resistor driven into the ground, center fed
through a 9:1 balun."

A 110 ft. center-fed inverted-V is certainly going to have extensive
losses in the resistors on most HF bands. After all, it is less than
1/2WL long on 75m and only 3 wavelengths long on 10m.
--
73, Cecil, W5DXP

"J. McLaughlin" wrote in message
...
Nice to hear from N8EE, another of Kraus' boys. 73 Mac N8TT


Please explain. Do you mean that I have read Kraus' book, or that I was one
of his students? (Which would be correct on both counts.)

Nice to hear from another N by 2 callsign. Not very many of us around, it
seems.

Jim
N8EE

Nice to hear from another N by 2 callsign. Not very many of us around, it
seems.

Jim
N8EE


One more -
Howdy from N2EE
making noise in contests as flagship of Nikola Tesla RC,
breaking records, exploring the frontiers of ocean fronts.

Yuri
da keykeeper of N2EE
and NT1E (Nikola Tesla #1 Engineer)

considered it to be my own call, but settled for the part of my old OK3BU

Oh my!
If you had a real E-mail address, I would have replied off-list. I am
not sure what is the first to go as we age, but you have forgotten that
we were both grad students of JDK. We have also both read his book!
73 Mac N8TT

--
J. Mc Laughlin - Michigan USA
Home:

"JLB" wrote in message
...

"J. McLaughlin" wrote in message
...
Nice to hear from N8EE, another of Kraus' boys. 73 Mac
N8TT


Please explain. Do you mean that I have read Kraus' book, or that I
was one
of his students? (Which would be correct on both counts.)

Nice to hear from another N by 2 callsign. Not very many of us
around, it
seems.

Jim
N8EE

J. McLaughlin wrote:
After investigating a large set of traveling wave antennas (not
Beverage) I think that the smallest amount of power dissipated in the
terminating resistance was about 2 db.

Just modeled the subject antenna as well as I can. Without the
termination resistors, the antenna has a gain of +6 dBi on 3.8
MHz. With the termination resistors, according to EZNEC, the
gain drops to -10 dBi, a difference of 16 dB.
--
73, Cecil http://www.qsl.net/w5dxp

That might not be a fair comparison, since the pattern might be quite
different with and without the resistors. To determine what fraction of
the applied power is dissipated in the resistors, simply click the Load
Dat button.

Roy Lewallen, W7EL

Cecil Moore wrote:
J. McLaughlin wrote:

After investigating a large set of traveling wave antennas (not
Beverage) I think that the smallest amount of power dissipated in the
terminating resistance was about 2 db.


Just modeled the subject antenna as well as I can. Without the
termination resistors, the antenna has a gain of +6 dBi on 3.8
MHz. With the termination resistors, according to EZNEC, the
gain drops to -10 dBi, a difference of 16 dB.
--
73, Cecil http://www.qsl.net/w5dxp

Cecil Moore wrote:
J. McLaughlin wrote:

After investigating a large set of traveling wave antennas (not
Beverage) I think that the smallest amount of power dissipated in the
terminating resistance was about 2 db.


Just modeled the subject antenna as well as I can. Without the
termination resistors, the antenna has a gain of +6 dBi on 3.8
MHz. With the termination resistors, according to EZNEC, the
gain drops to -10 dBi, a difference of 16 dB.
--
73, Cecil http://www.qsl.net/w5dxp

The antenna described in this thread has been utilized by the military
for simple, easy to erect and fairly inexpensive field use.

I don't think that you will get any argument from anyone that a
resistance terminated antenna is not as efficient as a tuned dipole. The
benefit one receives from using a resistance terminated antenna is the
lack of having to use an antenna tuner (another misnomer) when operating
off resonance. I, personally, use a B&W folded resistance terminated
antenna. This antenna is far from efficient but I can make great changes
in operating frequency with out having to worry about matching the final
circuit to the antenna.

I would like to have a tuned dipole for each band/subband but have
neither the room nor the desire to do so.
Now if you go to the receiver and look at the signal strength meter,
s-meter, you will see that 16db is only about 1 to 1 1/2 s units. In
that a receiver can differentiate a signal down to a very small value
the loss is of only academic interest, except to the purists.

Dave WD9BDZ