back on topic,..

i still ponder if i put power into a superconducting antenna if their
is no resistance, and a given about of power would therefore 'stay' in
the antanna longer ie no resistance and a sorta flywheel effect exists
the fields would have to exist longer for fixed-given power , ..

seems that all adds up to more than a trival gain

Not really, no, at least not in the commoner cases.

Let's assume that you could find a superconductor which would be
truly superconducting even at RF frequencies (which today's
superconductors are not, I gather). So, you could cut the loss
resistance of the antenna to precisely zero, in this hypothetical
case.

According to a note Reg posted some time ago, "At 3.75 MHz the
resistance of 20 awg copper wire is 0.206 ohms per metre. Overall
end-to-end dipole resistance 8.24 ohms."

Using the hypothetical perfect superconductor (which may be
impossible) you might reduce this dipole resistance to zero. Great
reduction in loss, right?

Less than you'd think. Remember, the loss resistance of 8.24 ohms
appears in series with the antenna's radiation resistance (which is
due to the RF energy being radiated) which will be around 70 ohms for
an antenna in free space. With the loss resistance present, just
under 90% of the energy is radiated ("dissipated" in the "radiation
resistance"), and 10% turns into heat in the loss resistance.

Getting rid of the loss resistance entirely will thus increase your
radiated power by only about 10% - a small fraction of one dB.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
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The fact that superconductors have zero resistance above DC isn't a
limitation of today's technology (although technology limitations cause
current high-temperature superconductors to have resistivity greater
than theoretically possible), but a fundamental property of the nature
of superconductors.

What I'm saying is that a "truly superconducting", "hypothetical
perfect" superconductor has finite resistance at any frequeny above DC.
Imagining a material that has zero resistivity at frequencies above DC
requires imagining something other than a superconductor.

Roy Lewallen, w7EL

Dave Platt wrote:
. . .
Let's assume that you could find a superconductor which would be
truly superconducting even at RF frequencies (which today's
superconductors are not, I gather). So, you could cut the loss
resistance of the antenna to precisely zero, in this hypothetical
case.

. . .
Using the hypothetical perfect superconductor (which may be
impossible) you might reduce this dipole resistance to zero. Great
reduction in loss, right?
. . .

In article ,
Roy Lewallen wrote:

The fact that superconductors have zero resistance above DC isn't a
limitation of today's technology (although technology limitations cause
current high-temperature superconductors to have resistivity greater
than theoretically possible), but a fundamental property of the nature
of superconductors.

What I'm saying is that a "truly superconducting", "hypothetical
perfect" superconductor has finite resistance at any frequeny above DC.
Imagining a material that has zero resistivity at frequencies above DC
requires imagining something other than a superconductor.

Roy Lewallen, w7EL

Dave Platt wrote:
. . .
Let's assume that you could find a superconductor which would be
truly superconducting even at RF frequencies (which today's
superconductors are not, I gather). So, you could cut the loss
resistance of the antenna to precisely zero, in this hypothetical
case.

. . .
Using the hypothetical perfect superconductor (which may be
impossible) you might reduce this dipole resistance to zero. Great
reduction in loss, right?
. . .

well seems everyone is 'strictly' (narrow) focused on the antenna's
resistence loss, i mentined it as the starting point as that is first
thing i think of when it goes critical... however one the resistance
drops, other effects take place no? both in the material and in respect
to other forces aside from just resistance, once it reaches near 0 and
begins being a superconductor

guess i won't know until i build it and mesure it i wanted to try 10m
really but 2m might be easier to keep chilly(0) and i am looking
foward to rig it i've got most of the stuff i think i need so far

i'd also like to build a superconductie ocilator, i'd suspect that i
could power it using a truly small ammount of power?