In TV broadcasting reflections from the antenna back to the transmitter will
be reflected by the transmitter to the antenna and the signal will be
rebroadcast albeit at somewhat less power. Then depending on the length of
transmission line the viewer may see ghosting.
In audio I don't know why and I have run my Collins 30S-1 into ladder line
with a 14 to SWR with no one except me knowing!

--

73
Hank WD5JFR
"Richard Clark" wrote in message
...
On Sun, 5 Jun 2005 10:02:17 -0400, "Fred W4JLE"
wrote:

You have created an all encompassing case from the original SWR of 1.7:1

Thanx Fred,

No one has ever been able to answer when the Transmitter rereflects
energy, why they need a tuner.

73's
Richard Clark, KB7QHC

On Sun, 05 Jun 2005 21:58:06 GMT, "Henry Kolesnik"
wrote:

In TV broadcasting reflections from the antenna back to the transmitter will
be reflected by the transmitter to the antenna and the signal will be
rebroadcast albeit at somewhat less power.

On Sun, 05 Jun 2005 21:58:06 GMT, "Henry Kolesnik"
wrote:

In TV broadcasting reflections from the antenna back to the transmitter will
be reflected by the transmitter to the antenna and the signal will be
rebroadcast albeit at somewhat less power.

Hi Hank,

That would pretty much reveal the SWR if we knew, wouldn't it? If
"somewhat less power" was in 1.2:1 ratio, we wouldn't care so much,
but how would the viewer feel about such service?

Then depending on the length of
transmission line the viewer may see ghosting.

I think we, or another correspondent and I have dealt with that at one
time. At the time I believe it was called "fringing," not "ghosts."
The difference being that what were called ghosts at the dawn of the
TV era were separated by fractions of an inch rather than fractions of
a mm. As such, ghosts couldn't have been originated by anything
shorter than mile length transmission lines that were poorly
terminated at both ends. Instead, ghosts were actually transmission
path length differentials in a multipath situation.

In audio I don't know why and I have run my Collins 30S-1 into ladder line
with a 14 to SWR with no one except me knowing!

Well, if this is meant to be analogous to fringing/ghosting, I suppose
its because a microsecond blur at AF is entirely inaudible. Or are we
speaking of SSTV? However, this begs the question, How did you know?
All the Collins equipment I taught at school didn't come with a SWR
meter. It was wholly unnecessary if you performed the standard
tune-up. Matter of fact, back then the only SWR meter I saw was for
Ham gear. The finals' tank performed every function of matching as
any tuner.

However, with the KWT-6, we did use an external tuner, 180-V1
(although I may have this mixed up with another model), for coax
feedlines. This was more for its automatic feature where the
transmitter could be tuned up with a 50 Ohm load, and the automatic
tuner simply did the job of presenting it with the transformed load.

However, returning to the point of a transmitter rereflecting a
reflection; I know the bare KWT-6 into ladder line employs its tank to
protect its final tubes. Without that safeguard, I have seen plates
melt - something no one here wants to call dissipation lest it be
evidence of an internal resistance. The bare tubes with their native
very hi Z would rereflect like nothing else - and this begs the
observation - how could you get original any power out of them, past
the tremendous mismatch? The tuner/final tank comes back into the
equation, and rereflection goes out the window as a property of the
transmitter and returns to the domain of matching.

If anyone wants to constrain the entire crusade of the rereflecting
transmitter to the tube set feeding ladder line - then feel free to do
so. However, I don't think I've ever seen a mobile tube rig feeding
ladder line - no doubt one day I will. We will probably talk about
efficiency. :-)

73's
Richard Clark, KB7QHC

However, I don't think I've ever seen a mobile tube rig feeding
ladder line - no doubt one day I will. We will probably talk about
efficiency. :-)

It was done in 1936.
http://web.wt.net/~nm5k/mobile36.jpg
Cover pix from a 1936 QST...Forgot
what month...
But I still think I prefer coax...
Their "ladder line" looked to be a twisted wire feeder.
The call on that vehicle was W9MSY...
With the short feedline run on a mobile,
even coax is pretty low loss...
I never used an SWR meter when I was a
novice...I had an old viking valiant that would
tune nearly anything...You didn't need a meter...
You just loaded it up to full plate current and went
with it...My TS 830 is like that to a lesser extent..
If it loads within the loading range, it's good nuff...
No point in even putting a meter on it...Adding a
tuner, would just add some loss...MK

On 6 Jun 2005 02:40:52 -0700, wrote:

However, I don't think I've ever seen a mobile tube rig feeding
ladder line - no doubt one day I will. We will probably talk about
efficiency. :-)

It was done in 1936.
http://web.wt.net/~nm5k/mobile36.jpg
Cover pix from a 1936 QST...Forgot
what month...
But I still think I prefer coax...
Their "ladder line" looked to be a twisted wire feeder.
The call on that vehicle was W9MSY...

Hi Mark,

Hmmm, the picture's kinda small, and the line looks like coax - or
maybe close ladder line. I will take your word for it as it makes my
track record for accuracy complete. :-)

Well, almost complete. Is the guy holding his pinkie to the radiator
measuring efficiency?

As a sidebar, the police were working 160M mobile back then too.
Seems coax was hardly an off-the-shelf item. Think they used ladder
line too? More probably direct feed.

73's
Richard Clark, KB7QHC

Hi Richard
Please tell me more about melting the finals and a bit more explanation of
what was happening?
tnx
Hank
"Richard Clark" wrote in message
...
On Sun, 05 Jun 2005 21:58:06 GMT, "Henry Kolesnik"
wrote:

In TV broadcasting reflections from the antenna back to the transmitter
will
be reflected by the transmitter to the antenna and the signal will be
rebroadcast albeit at somewhat less power.

Hi Hank,

That would pretty much reveal the SWR if we knew, wouldn't it? If
"somewhat less power" was in 1.2:1 ratio, we wouldn't care so much,
but how would the viewer feel about such service?

Then depending on the length of
transmission line the viewer may see ghosting.

I think we, or another correspondent and I have dealt with that at one
time. At the time I believe it was called "fringing," not "ghosts."
The difference being that what were called ghosts at the dawn of the
TV era were separated by fractions of an inch rather than fractions of
a mm. As such, ghosts couldn't have been originated by anything
shorter than mile length transmission lines that were poorly
terminated at both ends. Instead, ghosts were actually transmission
path length differentials in a multipath situation.

In audio I don't know why and I have run my Collins 30S-1 into ladder line
with a 14 to SWR with no one except me knowing!

Well, if this is meant to be analogous to fringing/ghosting, I suppose
its because a microsecond blur at AF is entirely inaudible. Or are we
speaking of SSTV? However, this begs the question, How did you know?
All the Collins equipment I taught at school didn't come with a SWR
meter. It was wholly unnecessary if you performed the standard
tune-up. Matter of fact, back then the only SWR meter I saw was for
Ham gear. The finals' tank performed every function of matching as
any tuner.

However, with the KWT-6, we did use an external tuner, 180-V1
(although I may have this mixed up with another model), for coax
feedlines. This was more for its automatic feature where the
transmitter could be tuned up with a 50 Ohm load, and the automatic
tuner simply did the job of presenting it with the transformed load.

However, returning to the point of a transmitter rereflecting a
reflection; I know the bare KWT-6 into ladder line employs its tank to
protect its final tubes. Without that safeguard, I have seen plates
melt - something no one here wants to call dissipation lest it be
evidence of an internal resistance. The bare tubes with their native
very hi Z would rereflect like nothing else - and this begs the
observation - how could you get original any power out of them, past
the tremendous mismatch? The tuner/final tank comes back into the
equation, and rereflection goes out the window as a property of the
transmitter and returns to the domain of matching.

If anyone wants to constrain the entire crusade of the rereflecting
transmitter to the tube set feeding ladder line - then feel free to do
so. However, I don't think I've ever seen a mobile tube rig feeding
ladder line - no doubt one day I will. We will probably talk about
efficiency. :-)

73's
Richard Clark, KB7QHC

On Mon, 06 Jun 2005 15:05:43 GMT, "Henry Kolesnik"
wrote:

Please tell me more about melting the finals and a bit more explanation of
what was happening?

Hi Hank,

Direct observation offered a glowing plasma between the filament and
the plate. It was football shaped rather than beam-like or an
amorphous cloud. One point of the football touched the cherry red
plate. Following a quick power-down, that point on the plate did not
exist anymore as there was a hole. Couldn't really tell, but no doubt
the grid suffered just as much in its own way.

I suppose plates have become more robust over the years since that
amazing demonstration. I helped fix one friend's Amp when it failed
along with his antenna (or t'other way round as the chain of causality
would suggest). His Amp simply quit working suddenly during bad
weather. Fuses checked - OK. No interlocks were open - OK. The tube
looked good at a glance - OK. HV Supply looked good - OK. The
filaments failed to light up - odd, but consistent. Time to crack
open the case. Pulled the tube and measured its filament continuity -
OK. Measured filament supply - OK. Things were really getting
strange. Time to bust the chassis open and really look. There on the
baseplate were several small pools of solder in a circular pattern -
how odd. Close scrutiny of connections revealed bright and soldered
wires to everything - OK. Time to look at the tube again. Every pin
was solder free - that was on the chassis base plate. [dirge played
here] The filaments' wires were making enough contact to measure
continuity, but no where enough to support real power.

In other tubes I've seen the heat become so extreme that the glass
envelope slumped into the vacuum and enclosed the plate structure like
taffy. This didn't even crack the glass (or it had simply re-fused).
Tube still worked afterwards though (so I would suppose the glass
never cracked). One occasion was actually due to a bias problem
created when the cathode load shorted. Lack of bias protection sent
the circuit into massive conduction. Of course the short came about
because of an initial excessive conduction (surprising in its own
right because the common failure mode is to open).

I've also seen stressed thyratrons so mismatched that they filled the
workspace with their purple glow like a floodlight. Thankfully fuses
work as I did not want to be near that final testimony.

Now, that was the short list of Bottle failures. I have another list
of melted state failures too, but their evidence is usually better
hidden and less dramatic - heat sinking generally spreads the risk,
so to speak. And speaking of heat sinks, I've drawn a number of
blisters from those that normally only warmed my hand. Note there
should be emphasis on normally warm and the obvious contradiction with
blisters.

Experience with failure has strongly correlated with heat and
mismatch. Heat was born by resistance. Resistance is part of life
and amplifiers. Heat comes in two forms. Slow-like, which is
generally current based; and sudden, which is generally voltage based.
I've felt along heatsinks immediately following failure that were as
cool/tepid as usual, or ominously cooler! The sudden heat of arc-over
in silicon can destroy just as effectively as the long slow broil of a
plate turning to slag.

Every mismatch in the Amateur experience is a probablistic spin of the
wheel of misfortune. Sometimes the wheel stops on the slow bake that
aborbs into heatsinks and you notice unusual smell, or your fan
running on too long - Quick! do something, and you survive. Other
times there's the snap of finality. Both of these examples are for
those with keen senses, and often failure comes as a whimper.

Most suffers usually discover what matching is for, even if they don't
know how it works.

73's
Richard Clark, KB7QHC

Richard Clark wrote:
Every mismatch in the Amateur experience is a probablistic spin of the
wheel of misfortune. Sometimes the wheel stops on the slow bake that
aborbs into heatsinks ...

Current maximum, Ifor+Iref in phase. Vtot = |Vfor|-|Vref|

Other times there's the snap of finality.

Voltage maximum, Vfor+Vref in phase. Itot = |Ifor|-|Iref|
--
73, Cecil http://www.qsl.net/w5dxp


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Richard

I've seen 3-500Z where the solder had melted out of the filament pins.

I have some 811 from my 30L-1 that have holes in the plates, they still work
quite well. It's been 15 years since I recall finding the holes in the
plate sides and replacing. In additon I can't recall the reason for the
holes but it had to be either
1. overdriving (which I don't think I did, 100 watt Icom)
2. high swr which I know has been over 10 to 1, but I can't see how that
could do it..
3. Light loading

But in any event for something to melt we need dissipation and only
resistance can do that!

--

73
Hank WD5JFR
Still learning, un-learning and re-learning

On Mon, 06 Jun 2005 20:52:52 GMT, "Henry Kolesnik"
wrote:

But in any event for something to melt we need dissipation and only
resistance can do that!


Hi Hank,

Unfortunately as much as you and I agree on that bedrock principle,
others with Simpson Ohmmeter in hand would glare goggle eyed at us and
say that plate has no resistance to speak of and that no amount of
current through its Ohmic resistance could ever bring about enough
heat to produce the effects so obviously witnessed. One of the most
enraging questions I've asked
"If it is not the value I've offered, what value is it?"

Well, I've never been given a quantitative answer, however I've seen
enough carefully crafted mathematical proofs in this group to replace
substantive results so easily seen. There is some irrefutable logic
in circulation that clearly reveals that what we've experienced just
couldn't be.

Glasses will be need to be readjusted for such extreme myopic
aberrations. There are two principles involved in what is called
Plate Resistance, and the first and foremost is not even related to
the plate at all. It is called the work function of the cathode
emissivity. So, in fact it is more proper to refer to this usual loss
as Cathode Resistance, not Plate Resistance. The cathode is the
fundamental limit on power generated.

What Plate Resistance is, is the ill termed substitution for Plate
dissipation. If folks want to work their Simpson, they would blow an
aneurysm trying to measure the resistance from cathode (filaments have
the same work function issue too) to plate. In fact, the hobby horse
argument of it is not resistance at all, but some figurative charting
artifice called a "load line" usually appears in the last gasp.

Plate Dissipation is resistance clear and simple in spite of the
failure of conventional tools to measure a common physical property.
Newton would have recognized it, it is called inertia.

Once the work function is overcome (the job of the grid), then Plate
voltage dominates through the acceleration of charge beyond the grid,
toward the plate. That stream of electrons (and there is no doubt
about actual current flow in easily counted, significant populations
of electrons) is elevated to 90% the speed of light. This current
flow is entirely different from what current flows in the remainder of
the Plate load. That is also known as displacement current and
electrons are shuffling along at a placid meter per second rate.
Plate current and displacement current are equal in amplitude and
phase, but not in motion nor kinetics.

NOW. When that same stream encounters the Plate - WHAM! If anyone
here has walked into the wall, and NOT encountered resistance, then we
will call you Casper.

Inertia reveals that to slow a mass in a distance results in
acceleration (negative in this instance) and that property is called
Force. Force over time expends calories and is expressed in any
number of systems and units - Watts is one, Degrees is another. We
could abstract to Horsepower and Candelas (the plate glows too).

We know the speed, not many here would give it much though, but none
would know the length interval of going at that speed to going zero
(0). It is roughly two atoms distance into the metal of the plate. I
will leave those calculations of Force to the student to compute or I
can provide it from notes of correspondence with Walt Maxwell and
Richard Harrison from a round robin discussion several years ago.

Hank, does this fulfill your earlier question as to "what" is
happening? I first gave you many examples, I hope this segue into
real physics fills in their actuality. Too many correspondents demand
that I open the source and point at a 50 Ohm carbon composition
resistor that is the "source resistance."

73's
Richard Clark, KB7QHC