Dummy Load Antenna
 

"Howard Kowall" wrote in
:

Has anyone ever tried putting a dipole antenna up with the center
insulator being a high power 50 ohm dummy load,then connecting the
dipole elements across the dummy load.This would always keep a
suitable match at 50 ohms and satisfy the transceiver.Would most of
the power go to the dummy load and not the elements and wouldn't
radiate.In thinking about this it all logically makes sense the load
would really never change or would it have some reactance with the
dipole elements. Thanx All
Howard
VE4ISP

Firstly, your proposal does not produce a 50 ohms antenna at all
frequencies. Your circuit analysis skills are lacking.

Various antennas include a resistance somewhere, and although it means
loss, it limits the feedline VSWR excursions with frequency and the loss in
the resistor may be more than offset by the reduction of feedline loss at
some frequencies.

Owen

Dummy Load Antenna
 

Owen Duffy writes:

Various antennas include a resistance somewhere, and although it means
loss, it limits the feedline VSWR excursions with frequency and the loss in
the resistor may be more than offset by the reduction of feedline loss at
some frequencies.

Not so useful for most amateur applications, but very useful for what
remains of professional HF radio. Frequency agility is often required,
particularly by the military, and operators either don't have time, or
skill, to fiddle with antenna tuners. Unless you are manpack portable,
the loss of signal can be made up by increasing power.

Automatic antenna tuners are getting ever better, though. May be these
designs are getting less popular.

LA4RT Jon

Dummy Load Antenna
 

In article , says...


Has anyone ever tried putting a dipole antenna up with the center insulator
being a high power 50 ohm dummy load,then connecting the dipole elements
across the dummy load.This would always keep a suitable match at 50 ohms
and satisfy the transceiver.Would most of the power go to the dummy load and
not the elements and wouldn't radiate.In thinking about this it all
logically makes sense the load would really never change or would it have
some reactance with the dipole elements.
Thanx All
Howard
VE4ISP

That is very similar to what the Maxcom Antenna Matcher
did. It was reviewed (and panned) in November 1984 QST.
As you suspected, almost all the power would go into the
dummy load and very little would be radiated.

Honestly, it's not a very good idea. :-)

73,
Bob
K3PH

--
+----------------------------------------------+
| Bob Schreibmaier K3PH | E-mail: |
| Kresgeville, PA 18333 | http://www.dxis.org |
+----------------------------------------------+

Dummy Load Antenna
 

Bob Schreibmaier wrote:
In article , says...

Has anyone ever tried putting a dipole antenna up with the center insulator
being a high power 50 ohm dummy load,then connecting the dipole elements
across the dummy load.This would always keep a suitable match at 50 ohms
and satisfy the transceiver.Would most of the power go to the dummy load and
not the elements and wouldn't radiate.In thinking about this it all
logically makes sense the load would really never change or would it have
some reactance with the dipole elements.
Thanx All
Howard
VE4ISP

That is very similar to what the Maxcom Antenna Matcher
did. It was reviewed (and panned) in November 1984 QST.
As you suspected, almost all the power would go into the
dummy load and very little would be radiated.

Honestly, it's not a very good idea. :-)


This one is meant to be a poor antenna, for use at really close distances.

http://www.wa0dx.org/wa0itp/dlspecial.html


Here is the gold standard, the MaxCom. If you gan get the link, QST had
a review. It was a toroid, and 3 resistors. Apparently a very high
quality dummy load (these things cost between 600 to 900 dollars!

http://www.eham.net/articles/14905


Had great SWR tho'!

- 73 de Mike N3LI -

Dummy Load Antenna
 

On Oct 9, 3:27*pm, Michael Coslo wrote:
Bob Schreibmaier wrote:
In article , says....

Has anyone ever tried putting a dipole antenna up with the center insulator
being a high power 50 ohm dummy load,then connecting the *dipole elements
across the dummy load.This would always keep a *suitable match *at 50 ohms
and satisfy the transceiver.Would most of the power go to the dummy load and
not the elements and wouldn't radiate.In thinking about this it all
logically makes sense the load would really never change or would it have
some reactance with the dipole elements.
Thanx All
Howard
VE4ISP

That is very similar to what the Maxcom Antenna Matcher
did. *It was reviewed (and panned) in November 1984 QST.
As you suspected, almost all the power would go into the
dummy load and very little would be radiated.

Honestly, it's not a very good idea. *:-)

This one is meant to be a poor antenna, for use at really close distances..

http://www.wa0dx.org/wa0itp/dlspecial.html

Here is the gold standard, the MaxCom. If you gan get the link, QST had
a review. It was a toroid, and 3 resistors. Apparently a very high
quality dummy load (these things cost between 600 to 900 dollars!

http://www.eham.net/articles/14905

Had great SWR tho'!

- 73 de Mike N3LI -- Hide quoted text -

- Show quoted text -

Once I joke about using a CB groundplane with a 10 db pad for an all
band antenna.
I thought about this for a while and decided to try it. I did nt have
to use 10 db maybe it was only 3db or 6db I cant remember now
to get an antenna that my soliddtate transceiver with no tuner was
happy with on allHF bands. I was fairly amazed at how well the
antenna worked or at least amazed that it did work at all.

Jimmie

Dummy Load Antenna
 

On Oct 8, 1:07*pm, John Smith wrote:
Howard Kowall wrote:
Has anyone ever tried putting a dipole antenna up with the center insulator
being a high power 50 ohm dummy load,then connecting the *dipole elements
across the dummy load.This would always keep a *suitable match *at 50 ohms
and satisfy the transceiver.Would most of the power go to the dummy load and
not the elements and wouldn't radiate.In thinking about this it all
logically makes sense the load would really never change or would it have
some reactance with the dipole elements.
Thanx All
Howard
VE4ISP

When you run a 73 ohm "resistor" and a 50 ohm resistor in parallel?

You would need a balun (rf transformer) to match to that antenna ...

Then you would need a suitable name for it. *Let me see, we are mating
up a "dummy load" with a "dipole." *How about "Dummy-Pole?" *grin

Regards,
JS

I'm glad you called it a 'balun (rf transformer)' instead of a 'balun
(CM Choke)'. Did Cecil review this before you posted it?

Dummy Load Antenna
 

That is very similar to what the Maxcom Antenna Matcher
did. It was reviewed (and panned) in November 1984 QST.
As you suspected, almost all the power would go into the
dummy load and very little would be radiated.

Honestly, it's not a very good idea. :-)

73,
Bob
K3PH

Hello, and generally not if maximizing operating efficiency (the portion
of available transmitter power that is being radiated by the antenna) is
of concern. However, placing a low-loss pad between the output of one
device and the input of another can be a simple, inexpensive broadband
matching technique if the power loss in the pad can be tolerated .
Sincerely, and 73s from N4GGO,

John Wood (Code 5550) e-mail:
Naval Research Laboratory
4555 Overlook Avenue, SW
Washington, DC 20375-5337

Dummy Load Antenna
 

JIMMIE wrote:

Once I joke about using a CB groundplane with a 10 db pad for an all
band antenna.
I thought about this for a while and decided to try it. I did nt have
to use 10 db maybe it was only 3db or 6db I cant remember now
to get an antenna that my soliddtate transceiver with no tuner was
happy with on allHF bands. I was fairly amazed at how well the
antenna worked or at least amazed that it did work at all.


What is more, you didn't have to spend 600 dollars for a bad antenna.


- 73 de Mike N3LI -

Dummy Load Antenna
 

J. B. Wood wrote:
That is very similar to what the Maxcom Antenna Matcher
did. It was reviewed (and panned) in November 1984 QST.
As you suspected, almost all the power would go into the
dummy load and very little would be radiated.

Honestly, it's not a very good idea. :-)

73,
Bob
K3PH

Hello, and generally not if maximizing operating efficiency (the portion
of available transmitter power that is being radiated by the antenna) is
of concern. However, placing a low-loss pad between the output of one
device and the input of another can be a simple, inexpensive broadband
matching technique if the power loss in the pad can be tolerated .
Sincerely, and 73s from N4GGO,


But as a good operating practice, Hams usually want to have efficient
ways to transfer their limited power.

It's in that realm between extremes - the Person who never puts up an
antenna because nothing is perfect enough, and the person who is willing
to waste almost all their power in the name of Low SWR, or maximum
convenience.

IMO, it's best to settle somewhere towards the more efficient end of
that group.

Which I guess is why I have a big ungainly Bug-Catcher type antenna on
the car instead of a short and cute whip.

- 73 de Mike N3LI -

Dummy Load Antenna
 

In article , Michael Coslo
wrote:

Which I guess is why I have a big ungainly Bug-Catcher type antenna on
the car instead of a short and cute whip.

- 73 de Mike N3LI -

Hello, and you can have a physically short and efficient whip if you
choose an appropriate frequency band ;-). Now what ever happened to those
cute car-mount cell phone antennas? Guess they're in antenna heaven along
with the K40s. Sincerely,

John Wood (Code 5550) e-mail:
Naval Research Laboratory
4555 Overlook Avenue, SW
Washington, DC 20375-5337