On Thu, 13 Oct 2005 01:43:48 GMT, Cecil Moore wrote:


and not to be a myth at all. There's 104.17 watts of forward power
through the Bird and 4.17 watts of reflected power back through the
Bird. Why does the Bird ignore those actual power values?

I did not report or even measure such a thing.

It is your report based on something that you know or something that
you measured without evidence of either measurements or detail of
construction.

With respect Cecil, the statement is more an elaboration of the myth
than convincing support for it.

This unsubstantiated premise seems the basis for nearly a hundred
posts by many.

Owen
--

Owen Duffy wrote:
On Wed, 12 Oct 2005 22:09:51 GMT, Owen Duffy wrote:
The myth: Measurements with a Bird 43 of the conditions on the
Thruline section are invalid unless it has some minimum length of 50
ohm line on both sides of itself.

Can I offer the suggestion that the key to understanding why this is
so, it to understand the sampler.

Again Owen, your own experiment using 75 ohm coax on each side of
the Bird proved why the above is not a myth. The Bird didn't read
the correct forward power on the 75 ohm coax. The Bird didn't read
the correct reflected power on the 75 ohm coax. The SWR calculated
using the Bird's readings does not represent the SWR on the 75 ohm
coax.

The proportions calibrate the instrument for a specific V/I ratio.

Yes, that ratio is 50 ohms for the Bird. Only a piece of 50 ohm
coax will guarantee that Vfor/Ifor=Vref/Iref=50 ohms. You proved
that a piece of 75 ohm coax will not do it.

Did I need to mention environments?

No, but you should have. The Bird gives the correct forward and
reflected power readings on the attached coax only in a 50 ohm
environment. Your experiment proved that to be true.
--
73, Cecil http://www.qsl.net/w5dxp

wrote:
4.17 watts does not flow back thru the Bird as reflected power, and
the Bird, of course acknowledges.

Yes, I later realized that the Bird's internal feedline forms a
50 ohm Z0-match. Interference at the input and output of the Bird
causes no reflected energy to flow through the Bird. The reflected
energy from the load is re-reflected at the Bird output. The input
of the Bird causes reflections on the source side of the Bird. I
actually calculated all the interferring signals.

I acknowledge that the Bird does not report the actual forward/reverse
power in this example

That was the main point. If the Bird is embedded in something other
than a 50 ohm environment, it does not report the actual forward/reverse
power on the coax on either side of the Bird.
--
73, Cecil http://www.qsl.net/w5dxp

Richard Clark wrote:
Who would approach a Bird and expect it to in the first place?

Someone who says that the environment surrounding the Bird
doesn't matter?
--
73, Cecil http://www.qsl.net/w5dxp

Owen Duffy wrote:

Cecil Moore wrote:
and not to be a myth at all. There's 104.17 watts of forward power
through the Bird and 4.17 watts of reflected power back through the
Bird. Why does the Bird ignore those actual power values?

I did not report or even measure such a thing.

Since I realized the Bird forms a Z0-match at its output that
statement should be ammended to say: There 104.17 watts of forward
energy flowing in the 75 ohm coax on each side of the Bird and 4.17
watts of reflected energy flowing in the 75 ohm coax on each side
of the Bird. Why does the Bird ignore those actual power values
existing in the actual system?

100W--tuner---75 ohm coax---Bird--1/2WL 75 ohm coax--50 ohm load
Pfor=104.17W-- Pfor=104.17W-- 100W delivered
--Pref=4.17W --Pref=4.17W

The Bird is not reading the proper values of forward and reflected
power on the 75 ohm coax because it is embedded in a non-50 ohm
environment.
--
73, Cecil http://www.qsl.net/w5dxp

On Sat, 15 Oct 2005 03:27:43 GMT, Cecil Moore wrote:
Who would approach a Bird and expect it to in the first place?
Someone who says that the environment surrounding the Bird
doesn't matter?
On Sat, 15 Oct 2005 03:25:26 GMT, Cecil Moore wrote:
If the Bird is embedded in something other
than a 50 ohm environment, it does not report the actual forward/reverse
power on the coax on either side of the Bird.
Who would approach a Bird and expect it to in the first place?

On Sat, 15 Oct 2005 03:37:16 GMT, Cecil Moore wrote:
The Bird is not reading the proper values of forward and reflected
power on the 75 ohm coax
Who would approach a Bird and expect it to in the first place?

Richard Clark wrote:
Who would approach a Bird and expect it to in the first place?

Someone who says that the environment surrounding the Bird
doesn't matter?
--
73, Cecil http://www.qsl.net/w5dxp

Richard Clark wrote:
Who would approach a Bird and expect it to in the first place?

Someone who thinks reflections cannot be eliminated by 1/4WL
of thin-film?
--
73, Cecil http://www.qsl.net/w5dxp

On Sat, 15 Oct 2005 03:58:22 GMT, Cecil Moore wrote:
Someone who says that the environment surrounding the Bird
doesn't matter?
On Sat, 15 Oct 2005 03:25:26 GMT, Cecil Moore wrote:
If the Bird is embedded in something other
than a 50 ohm environment, it does not report the actual forward/reverse
power on the coax on either side of the Bird.
As you are the only one who maintains your own statement above, do you
really need a roll-call to differentiate yourself?