| [John Dore, I cannot now get6 hold of the manual on
the 109, which is at ftp://bama.sbc.edu/downloads/tek/109/tek%20109.v6.pdf
I used to be able to download it.]
[Key web page over the stuff below is http://www.ivorcatt.co.uk/96511.htm
and before that http://www.ivorcatt.co.uk/965.htm
]
I won't add your last email below to http://www.ivorcatt.co.uk/96511.htm
unless you ask me to. http://www.ivorcatt.co.uk/96511.htm is the
historic record of the ideas that developed yesterday, culminating
in the 100 ohm series resistor in the inner conductor, replacing
your proposed (and my proposed) scope probes. You seem to think
the 100 ohm was an addition. No. The original idea I came up with
two months ago was not essentially to probe along the 40nsec coax.
It was to do things along the 40nsec coax. Now we see that the most
fruitful, easy thing to do is not to probe the 40nsec coax, but
to introduce a series resistor. Then all we have to do is to probe
the outside coax, beyond the reed relay, and observe the waveform.
This waveform will start at 4v, then after a while fall to 2v. The
time for 4v and the time for 2v will correlate with twice the time
distance along segments of the 40nsec coax which have not been tampered
with.
The idea of putting probes in the 40nsec coax rather than a series
resistor is now downgraded to a more difficult subsidiary experiment.
I am very conscious of the historic significance of these developments,
and that is why I am careful to record the developments over the
last few hours.
Initially last night I made a mistake in detail over my prediction
of the waveform. I corrected it half an hour later. I may still
be mistaken, but I doubt it. Anyway, the main thrust of http://www.ivorcatt.co.uk/96511.htm
is surely correct. It is that energy current cannot get past the
100 ohm unless helped to do so by energy current ravelling in the
opposite direction. If that latter is not present, then the voltage
amplitude of the eastwards travelling energy current drops to half.
The other half is dissipated in the 100 ohm resistor.
The half volt waveform is of course only one quarter of the poweer
of the incident energy current. The formula is v2/Z.
I now think I need to add this email to the other one, because
all discussion might help to clarify the present situation for the
reader.
Ivor 9.20am 28july09.
@@@@@@@@@@@@
----- Original Message -----
From: "Forrest Bishop" <forrestb@ix.netcom.com>
To: "ivor catt" <ivorcatt@electromagnetism.demon.co.uk>
Cc: "John Raymond Dore" <johnrdore@googlemail.com>
Sent: Tuesday, July 28, 2009 2:28 AM
Subject: Re: 109 and josephson
> Dear Ivor,
>
> I'm very happy you approve!
>
> Maybe the probe's gate itself should be moved away from the
probe's junction with the primary coax. All that the primary TEM
waves know about is that junction. http://www.ivorcatt.com/1_4.htm
There are three TEM waves resulting from each initial TEM wave-
injected, reflected and transmitted waves, instead of the 4 resultant
waves of Fig. 14.. The reflected wave adds a complication, as it
adds to the other (west or east) transmitted TEM wave. (west adds
to east and vice versa). Another reason to make all the probe impedances
different from each other.
>
> A high impedance probe coax lead connects into a 50 ohm primary
coax. If the total experiment length is e.g. 100 ns, then make the
probe's lead-coax longer than that, so the reflected wave from the
gate of the probe cannot be injected back into the primary coax
until after the interesting data has been recorded. Then the impedance
of the probe itself becomes irrelevant, only its response time matters.
The time delay to the gate has to be calculated, verified, and accounted
for of course.
>
> If mixed-impedance coax connectors are not available it may
be possible for me to fabricate them on my mini CNC mill, etc. I
have several partial designs for these, designed to give a clean
shift from one impedance to another with a minimum of ancillary
"noise" waves This was done as part of a series of such
experiments I'd like to run some day, preferably with you.
>
> Forrest
>
>
> -----Original Message-----
>>From: ivor catt <ivorcatt@electromagnetisn.demon.co.uk>
>>Sent: Jul 27, 2009 2:01 PM
>>To: Forrest Bishop <forrestb@ix.netcom.com>
>>Cc: John Raymond Dore <johnrdore@googlemail.com>
>>Subject: 109 and josephson
>>
>>This (below) is completely new.
>>Congratulations.
>>Because of the loading of a probe, I thought in terms of
only probing at one
>>point at one time. Thus, I was blocked off from the ideas
below by you.
>>
>>If the energy current travelling in the wrong direction
attenuates in its
>>travels, perhaps this will give evidence of its direction
of travel. The
>>last half of the resulting 80 nsec pulse will attenuate
twice, because it
>>passes the probe twice. The first half - the rightwards
travelling energy
>>current will attenuate only once. My immediate reaction
is to say that the
>>final 80nsec pulse should have small steps down, the first
few steps down
>>being only half of the later steps down. However, the last
few sentences
>>ignored the problem of initially charging to a steady unvarying
voltage
>>along its length. However, I think we can still do that,
before the relay
>>closes. Perhaps in this context we would consider only two
probes, one half
>>way along and another at the start of the infinitely long
coax cable.
>>I need to think more about this brilliant idea.
>>I think the charging source is via 1 megohm, but I have
not checked to
>>brochure on the www, it is only my memory telling me that.
>>I have not bothered to calculate it, but found on two websites
that
>>capacitance per foot is about 20pF. Thus, if the source
is through 1 Mohm,
>>then the charging time constant is 20 microseconds. Now
the time avilable
>>for each cycle, at 720 Hertz, is around 1 msec, sop there
is a margin of a
>>factor of 50.
>>
>>However, that does not deal with the loading of the inner
conductor by
>>probes, potentially upsetting the charging through 1 Mohm.
I need to know
>>what is the resistance (?impedance?) of the highest impedance
scope probe.
>>John Dore mentioned FET probe, but they may not be fast.
>>
>>Incidentally, I forgot that today's oscilloscopes record
a waveform, which
>>it did not do when I was active. John Dore didn't understand
my talk about
>>sampling and normal 'scopes, but did not realise I had forgotten
that a
>>sampling scope will record a very slow waveform, so it will
be fine. We
>>definitely use a sampling scope.
>>
>>@@@@@@@@@@
>>
>>It is extraordinary that I have just discovered
>>http://www.ivorcatt.co.uk/981.htm among my many papers.
I did not find the
>>last bit, but what is now on http://www.ivorcatt.co.uk/981.htm
is the
>>crucial part.
>>
>>This means that I drew Josephson into cattq in 1997, long
before Nigel Cook
>>pulled him in around 2004
>>
>>Ivor
>>
>>
>>----- Original Message -----
>>From: "Forrest Bishop" <forrestb@ix.netcom.com>
>>To: "ivor catt" <ivorcatt@electromagnetism.demon.co.uk>
>>Sent: Monday, July 27, 2009 3:17 PM
>>Subject: Re: 109
>>
>>
>>> Dear Ivor
>>>
>>> As a refinement, or complication, of this experiment
each probe along the
>>> line removes a portion of the energy from each (west
and east) TEM wave,
>>> according to the relative impedances (cf Catt on how
a voltmeter works).
>>> The initial experiment, analysis, and animations should
ignore this of
>>> course. A later experiment could introduce a lower
impedance probe at one
>>> or more of the test stations. The resulting attenuation
of each of the TEM
>>> waves would then be seen at the next adjacent stations,
to the west and to
>>> the east. In this way the lower impedance probe is
setting a definite
>>> identification marker for both of the waves. Each of
the probes could do
>>> the same, by making their input impedances all different
from each other.
>>>
>>> Forrest
>>>
>>
>>
>
.
.
|