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Fw: [Amps] Boycott New Chinese linear Amplifier

PA3DUV
 

The blood pressure is rising ;-)

Cheers, Dick
PA3DUV

----- Original Message -----
From: "Administrator" <amps@...>
To: <amps@...>
Sent: Wednesday, October 04, 2006 10:08 PM
Subject: Re: [Amps] Boycott New Chinese linear Amplifier


I told you morons to stop this thread. Nothing techinical here. Am I going to have to throw you all out of here. The list founder told me to clean up this mess and I will.

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Re: 3 - phase HV supply

PA3DUV
 

开云体育

Moin Peter,
?
Mains goes 5 volt down from 440 to 395, measured on the transformers primary terminals.
?
The plate transformer is over 45 kg, I lift it with my chain come-along and a sling around it.
Concerning the 2nd harmonic: I never measured that but did not receive complaints so far from guys listening in the 20 meterband while I was working DX on 40 ;-)
?
Cheers, Dick
PA3DUV
?
?
?

----- Original Message -----
Sent: Wednesday, October 04, 2006 8:32 PM
Subject: RE: [ham_amplifiers] Re: 3 - phase HV supply

Hi Dick,

That sounds like a rather poor regulation for a 3-phase power supply.
Is your mains voltage already dropping?
I guess the transformer might be a bit too small to deliver 10KW, or is the
3-phase p/s heavier then 45kg?
Here at 7,5KV the B+ is dropping to 7,25KV loaded by 3A (load C=2mmF)

I had a look at the DX4 manual. They use a simple pi-net with a balun
output, no pi-L?
How good is the harmonic supression of it? I calculate just 30dbs on the
second and 43dbs on the third harmonic.

73
Peter

________________________________

From: ham_amplifiers@yahoogroups.com [mailto:ham_amplifiers@yahoogroups.com]
On Behalf Of PA3DUV

The circuit diagram of the Emtron DX4 3 phase power supply can be found in
the
file section on
<>
It use the plate transformer in delta on the primary and star on the
secondary.
A FWD and 58 uf cap bank is used, output 3.2 kV, @ 3.5 amps peak the B+
drops to 3 kV

Cheers, Dick
PA3DUV




Chortle of the Week

Phil Clements
 

A post on the AMPS reflector that got by the censor today was from
Bob, W6TR; the thread was about the copying of the AL-811 amp in China.

"Isn't it time to bring the curtain down on this thread? Copying an
Ameritron amplifier is like trying to perform a hemorrhoid transplant."

Bob W6TR

This made my day!

(((73)))
Phil, K5PC


Re: 811 debacle

Hsu
 

That is a joke, he wan t to whip away on me, but he scram first !
73!Hsu


Re: Hi-pot tester

Hsu
 

Hi,Guillermo,
I think your square wave generator's freqence is too high?the
ignition automotive coils's is iron not ferrite, the frequence
must below kilo hertz
73! Hsu


u may be in the good direction; I did not tried with TV flyback
transformers, but did once some experiments with old ignition automotive
coils, excited with a square wave generator and a darlington transistor
amplifier. I could never get more than 400 volts pk-pk. With 13.8V supply.
The circuit was not optimized also due to lack of time for another tasks, but
I think one could get better results.
More experimentation is in order here.

Best regards
Guillermo - LU8EYW.

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Re: O.T. The "other" list ...aka .... Tom R @%&H

Mike Sawyer
 

开云体育

Jim said: "### what's he gonna do with a HB "medical linear"..... do a
little diathermy on 14.175 Mhz ? ?"
To quote Rich, "Chortle!"
Mod-U-Lator,
Mike(y)
W3SLK


Re: Hi-pot tester

GGLL
 

Hsu, you may be in the good direction; I did not tried with TV flyback transformers, but did once some experiments with old ignition automotive coils, excited with a square wave generator and a darlington transistor amplifier. I could never get more than 400 volts pk-pk. With 13.8V supply.
The circuit was not optimized also due to lack of time for another tasks, but I think one could get better results.
More experimentation is in order here.

Best regards
Guillermo - LU8EYW.

Hsu escribi:

Thanks! will
All Neon tranformer there has been replaced by Switching power supply.Old transformer
isn't easy to get now. There is another important reason,I often purchase NOS tubes, so,
it needs battery operated.
73! Hsu
----- Original Message -----
*From:* craxd <mailto:craxd1@...>
*To:* ham_amplifiers@...
<mailto:ham_amplifiers@...>
*Sent:* Thursday, October 05, 2006 7:06 AM
*Subject:* [ham_amplifiers] Re: Hi-pot tester
Hsu,
Most of the smaller commercial ones at around 4-5 kV use a neon
sign transformer. Those are not that heavy, nor big either. It's
according to what you have available there, but any sign company
can get you a used transformer cheap. You may have to use a doubler
or tripler, it's according to the output voltage of the transformer.
These are pretty low current, maybe 5 mA or so. It doesn't take
much.
Best,
Will
--- In ham_amplifiers@...
<mailto:ham_amplifiers%40yahoogroups.com>, "Hsu" <Jbenson@...> wrote:
>
> I want to build an Hi-pot tester, I have seen some design, Rich's
and W6CW,But I do not want use ac transformer.
> it is two heavy and need AC main power.I have some junk B/W and
Clour TV FBT, I think if I can be use in this project.
> I have a quertion, How much current the hi-pot tester should
supply?The another function of tester is burning of the "junk" between
two electrode,it needs more current.
> 73! Hsu
>


Re: Hi-pot tester

Hsu
 

开云体育

Thanks!?will
?? All Neon tranformer there has been replaced by Switching power supply.Old transformer
?isn't?easy to get now.?There is another important reason,I often ?purchase? NOS tubes, so,
?it needs battery operated.
? 73! Hsu
?

----- Original Message -----
From: craxd
Sent: Thursday, October 05, 2006 7:06 AM
Subject: [ham_amplifiers] Re: Hi-pot tester

Hsu,

Most of the smaller commercial ones at around 4-5 kV use a neon
sign transformer. Those are not that heavy, nor big either. It's
according to what you have available there, but any sign company
can get you a used transformer cheap. You may have to use a doubler
or tripler, it's according to the output voltage of the transformer.
These are pretty low current, maybe 5 mA or so. It doesn't take
much.

Best,

Will

--- In ham_amplifiers@yahoogroups.com, "Hsu" <Jbenson@...> wrote:
>
> I want to build an Hi-pot tester, I have seen some design, Rich's
and W6CW,But I do not want use ac transformer.
> it is two heavy and need AC main power.I have some junk B/W and
Clour TV FBT, I think if I can be use in this project.
> I have a quertion, How much current the hi-pot tester should
supply?The another function of tester is burning of the "junk" between
two electrode,it needs more current.
> 73! Hsu
>


Re: Rotary Switches

pentalab
 

--- In ham_amplifiers@..., jmltinc@... wrote:

I don't know a model 85 from a Model T, or a model 88 from a
Rocket 88
(remember those?). I can't hi-pot a switch online.

How can I select a candidate online, in a catalog, or at a hamfest
if no no
specifications are known or the switch has no identifying marks?

Thanks again,
### pretty tough. You can see and download ALL the detailed specs
of Multi tech switches at.....
industries.com/Default.htm

### Centralab JVC series switches are used in alpha.. and a lot
of other amps.

### You can look at contact surface area.. and also space
between contacts... contacts to rotor etc. Figure on 9 kv
per 1/4" 4.5 kv per 1/8" etc.

### B4 u get too carried away.. you have to figure whether u
want a PI- PI-L... how many KW.... how many bands, shorting or
non shorting switch... how many KV on anode of the tube etc.

### for 8877.... 3-500Z's.... etc.... a model #86 will work
fine. For 4-1000's... YC-156's 3000/6000 A7 triodes... and
also big tetrodes.... 1-3 wafers of the model 88/85 will work.

### for mono band amps.... u don't require a bandswitch of
course.....ditto with heavy duty roller inductor's.

### My buddy had a 1969 Delta 88 oldsmobile..... stupidest
thing he ever did getting rid of it..... 455 cu in V-8...
globs of torque !

Jim VE7RF


Re: Hi-

 

On Oct 4, 2006, at 3:25 PM, craxd wrote:

--- In ham_amplifiers@..., R L Measures <r@...> wrote:


From: R L Measures <r@...>
Date: October 4, 2006 11:52:44 AM PDT
To: ham_amplifiers@...
Subject: Re: [ham_amplifiers] Re: Hi-

Will -- My mistake, it was on p.71 of the September, 1994 issue of
QST magazine where Tom writes: "Although VHF and UHF parasitics are
undesireable effects. and must be avoided, there is no basis in
amplifier tube theory or actual experience to support such
conclusions. They are not supported by design theory or the
experience of recognized amplifier experts in the RF amplifier design
community that include Eimac, Siemens, ETO, Henry, and Ameritron."
Since ETO is Dick and Ameritron is Tom, Dick and Tom are "recognized
amplifier experts", and this according to a guy who says that Ni-Cr
alloys have reverse skin effect and that the conventions of AC
circuit analysis do not apply to R/L VHF parasitic
suppressors. . . . George Grammar, W1DF, QST Technical Editor
during the 1950s. was probably turning over in his grave.
Background: Around September of 1993, I received a letter from
QST Technical Topics Column Editor Paul Pagel asking me to write
another article for QST about amplifiers. The result was "The Nearly
Perfect Amplifier", which appeared in the January, 1994 issue of the
magazine. The article outlined things which a perfect or nearly
amplifier would have. Examples were step-start to limit inrush- I, T/R, R/T switching that was Faster than that of transceivers in order
to prevent hotswitching, filament-potential adjusting potentiometer
to maximize emissive life, lower-Q VHF parasitic oscillation
suppressors to improve stability, the use of a grid fusing element,a
glitch resistor in the HV+ lead to limit peak-I during an anomaly,
and potting the HV transformer to reduce hygroscopic absorbption and
improve heat transfer. The article apparently lit the fuse of Tom
Rauch, W8JI, (MFJ-Ameritron) and the even shorter fuse of Dick
Ehrhorn W0ID (!) (ETO/Alpha), whereupon they apparently began
kvetching to the magazine that they should be allowed to write a
rebuttal that would be published in Technical Topics. Quite probably
since MFJ and ETO were major advertisers in QST, this got QST's
attention and QST agreed to publish the rebuttal.
As I see it, publishing the rebuttal was the only fair thing to
do. However, to be fair, my reply to the abundance of questionable
statements made therein also needed to be aired. The problem was
that QST Editor Mark Wilson. AA2Z, refused. As a result, I launched
my Web site and published my reply to the rebuttal

so that QST subscribers could see what the QST Editor did not want
them to see.

Since you okay it : )
I relish such things.

Quote;

"The thing that gets Rich Measures in trouble is that his
writings HAVE been peer reviewed and been denounced as snake
oil by academics,
Tom Rauch an academician? -- he's never taken a class in the very
basis of RF amplifier design -- alternating current circuit analysis.



I didn't figure he did by some of the stuff he has said. One can
tell if someone has actually been taught something, or just trying
to quote things they've heard or read from unreliable sources.
I highly doubt he's ever did any actual research either. I know
what that's like as I'm still doing it on transformers and power
supplies. I've been doing it now for about two years straight.
I'm still finding out new things that I hadn't seen in other works.




responsible engineers from every major tube
builder,
The only person from a tube mfg that he got to go along with his
dicta was his buddy Reid Brandon, the Eimac Customer Relations guy -


It would about have to be as i've read the photocopy of your
letter from Eimac.



who told QST's Paul Pagel that Eimac's Chief Specifications Engineer,
Willis B. Foote was not authorized to tell me that gold-sputtering
from the grid was thought to be caused by a UHF oscillation
condition.




That would be a salesmans tone so as not to make ones think the
tubes were faulty.
The problem is not that the tubes are faulty, it's that some designers of amplifiers ignorantly chose to ignore C-feedback.


RF design engineers from many companies ranging from
amateur manufacturers to MRI/ISM amplifier builders and
several major broadcast transmitter manufacturers.
Guffaw. The clue word here is "many" because he fails to list the
companies.

Measures'
material has all the earmarks of a "good con" ... just enough
truth to give it a patina of believability to the untrained
and impressionable".
Thanks, Will.



No problem!








This all over Tom trying to argue that a control grid could
become positive.
It can and definitely does so in a grounded-grid amplifier during
most of the negative half of the driving cycle.

No, If you remember, I did say that that was the only case.
What he was getting at was it could become positive with the
grid disconnected from ground, and if I remember, there was
another way which we both collared him on.
With air in the tube, the grid can go positive provided that the
anode is sufficiently positive to make the O^2 and N^2 atoms ionize



Positive with respect to the cathode you mean? Terman calls
it less negative, see below.
Less negative is not necessarily positive.

...
...
A participant in a discussion can not be the censor of the
discussion
because it would stink even more than fresh feces. .
Yes, it has stunk since someone re-appeared on Amps after several
years of absence.

...
But he can't control us bailouts.



According to this nameless admin, he booted all of us out.

chortleicious
...
R L Measures, AG6K, 805.386.3734
r@..., , rlm@..., www.somis.org


Re: Hi-

Mike Sawyer
 

开云体育

Will said: "Positive with respect to the cathode you mean? Terman calls
it less negative, see below."
?
I remember that thread. Even a simpleton like me understood what you were saying and the point you were making. I often beleive he did this to demonstrate his arguementative skills, (which I didn't think too much of).
Mod-U-Lator,
Mike(y)
W3SLK


Re: Hi-pot tester

craxd
 

Hsu,

Most of the smaller commercial ones at around 4-5 kV use a neon
sign transformer. Those are not that heavy, nor big either. It's
according to what you have available there, but any sign company
can get you a used transformer cheap. You may have to use a doubler
or tripler, it's according to the output voltage of the transformer.
These are pretty low current, maybe 5 mA or so. It doesn't take
much.

Best,

Will


--- In ham_amplifiers@..., "Hsu" <Jbenson@...> wrote:

I want to build an Hi-pot tester, I have seen some design, Rich's
and W6CW,But I do not want use ac transformer.
it is two heavy and need AC main power.I have some junk B/W and
Clour TV FBT, I think if I can be use in this project.
I have a quertion, How much current the hi-pot tester should
supply?The another function of tester is burning of the "junk" between
two electrode,it needs more current.
73! Hsu


Re: O.T. The "other" list ...aka .... Tom R @%&H

pentalab
 

--- In ham_amplifiers@..., GGLL <nagato@...> wrote:

Well, apparently it was a spoof message, not sent by the
Admin. Anyway, I
left the list.

Best regards
Guillermo - LU8EYW.

### welcome aboard...... over 440 mesages here... and 119
members....

### Total number of new members is climbing daily.

### I find it amusing that Rauch designed that 3 x 811 amp........
[who in their right mind would actually design and build a 3 x 811
amp these days is beyond me].... then say it has a buncha
drawbacks... and needs to be improved ?

#### considering Rauch designed nearly everything MFJ sells....
including ant tuners with..get this Delrin Rod forms that melted
with 900 w [I guess they don't test anything]..... and
considering Rauch brags about all the Ameritron amps he
designed. [all of em]..... if that was me who designed any of that
stuff...... I'd make damn sure nobody ever found out who I
was.... I'd be embarassed !

### I'm told he was also involved with Dentron + Heath ??
Dentron, imo... never produced a single linear that was any good.
IMO.... some of this stuff being passed off as "linear amps"...
is not engineered at all..... it's ill conceived.

### For not much more $$$.... "they" coulda added simple
things... like a stnadby/operate switch on the heath's...
grid/cathode 3agc fuses... HV fuse... step start, safety
protection diodes.... real xfmr's, etc..... and ended up with a
much better built... "product".

### Go to Tom's website sometime. His AL-1500 looks
nice..... SO does the pix of the YC-156 10 kw+ output "medical
amplifier" in his workshop... complete with taps for 160-10m !

### what's he gonna do with a HB "medical linear"..... do a
little diathermy on 14.175 Mhz ? ?

later.......Jim VE7RF


Re: 811 debacle

 

On Oct 4, 2006, at 2:34 PM, craxd wrote:

I know it's poor form to talk about another group, but I have
to show this if others haven't seen it. About the 811 copy
Hsu shown. This admin, since his last post saying to stop,
let Tom whip away on Hsu I guess. However, when one made a
joke about it this morning, and I answered it, look what the
unknown admin had to say;

"I told you morons to stop this thread. Nothing techinical
here. Am I going to have to throw you all out of here. The
list founder told me to clean up this mess and I will".

Isn't the founder of the Amps list dead? Or that's what I
thought anyhow. He calls everyone morons, and wouldn't even
sign as Administrator this time, just left it blank. I think this
is more like the moron is on the other end. I just wonder why he's
never banned me yet? I also just double checked, it looks I was the
last to reply, and I was only wanting to know more about Chinese
tube factories. Here's all I said to provoke him;

"I'm like you, there's a bunch of other amps that are much better
candidates. Even in this case, Hsu's friend had to make modifications
and corrections to make it boatworthy. However, I have learned a great
bit from Hsu about the Chinese tube factories. I actually found that
very educational. I would like to talk to him about some other tubes
no longer available and who might revive them like the 6LF6. I could
sell a ton of them in the US right now".

This is the very reason why I quit posting any questions on the
list, and really quit helping. If you ask me, by him banning Rich,
he just made a martyr out of him instead of showing who's boss.
The amazing thing about Boss Tom is that he knew that I had previously used the censor bypass mailing list on three occasions to counter being censored, yet he went ahead and censored me. Clueless?

Sincerely,

Will






Yahoo! Groups Links










R L Measures, AG6K, 805.386.3734
r@..., , rlm@..., www.somis.org


Re: O.T. The "other" list

craxd
 

Guillermo,

The thing is, he blamed either Rich or one of use for doing it! I'm
also not satisfied he didn't do it. He could have been using an
alternate e-mail of his at the time, and after all the heat, he said
this to cover it up.

Best,

Will


--- In ham_amplifiers@..., GGLL <nagato@...> wrote:

Well, apparently it was a spoof message, not sent by the Admin.
Anyway, I
left the list.

Best regards
Guillermo - LU8EYW.

GGLL escribió:
It appears that the administrator of "the other" list loose a
screw. About
the chinese quality of tubes and amplifiers, the thread include
this message
from "the administrator":

"I told you morons to stop this thread. Nothing techinical here.
Am I going
to have to throw you all out of here. The list founder told me to
clean up
this mess and I will."

I now will definitely leave that list.

Best regards
Guillermo - LU8EYW.



Yahoo! Groups Links









Re: I hate the input network

craxd
 

Hsu,

Take a look at the link below. The amps uses a broadband input
tune network that I'd think could be used for the cathode the
same as it is on the grid in this one. It wouldn't hurt to give
it a try. It is set up with an attenuator in this one, but could
be modified I think. I've not looked at the schematic in a while,
I just remember somewhat that they done.



Best,

Will


--- In ham_amplifiers@..., "Hsu" <Jbenson@...> wrote:

The GG linear is very popular now, but most of them with input Pi
network for matching transistor driver.
it need at least six coils and 12 relays or switchs and some
adjusting work.why throw them off my linear amplifier?
The problem:if without input network,its driver will unmatched.In
negative cycle, the input impendance will becuume very big, it is a
bigest problem.Even in positive cycle, there is a problem, input
capacitance, so the input impendance is not "pure" resistance,if no
much more tube in parallel.
If we design a GG Push-pull amp, the problem should be solved. The
push-pull design only have 1/4 input/output capacitance in same tube'
amount.The onventional P-P design must with resonator in plate tank.
But I think it can be replace by a wideband P-P RF transfoemer, in
secondary, wen can add a Pi net work.Certainly, we can use the
transformer adjust the proportion of primary and secondary,let input
impendance to match with the transitor driver.
It is a good idea?
73! Hsu
my linear amp? resonance


Re: 811 debacle

 

On Oct 4, 2006, at 3:02 PM, craxd wrote:

This is too good to be true, from the admin;

"My apologies to the group for this ... someone at 30gigs.com
<localhost (www3.30gigs.com [67.15.217.15])> has spoofed the
e-mail address I use for administering this group. The "spoof"
is obvious from two points - the entry IP in the message header
and the lack of the automatic signature attached to each of my
postings".

"I have modified the group settings so the administrator account
cannot be (mis)used again. Unfortunately, this simply proves
that the e-mail address on ANY posting to the group can be forged
(spoofed). I suspect the group will see quite a bit of that
kind of childish behavior from the very same individual(s) who
are no longer welcome here".

73,

... Administrator
amps@...


I believe him about as far as I can thrown him.
Indeed.


Rich got the blame
for it! Did you spoof him Rich?
no

Rich has been spoofing the admin, you
spoofing Rich? LOL!!!!!!!!!!!
Tom Rauch is W8JI's worst enemy.

Best,

Will




--- In ham_amplifiers@..., "craxd" <craxd1@...> wrote:

I know it's poor form to talk about another group, but I have
to show this if others haven't seen it. About the 811 copy
Hsu shown. This admin, since his last post saying to stop,
let Tom whip away on Hsu I guess. However, when one made a
joke about it this morning, and I answered it, look what the
unknown admin had to say;

"I told you morons to stop this thread. Nothing techinical
here. Am I going to have to throw you all out of here. The
list founder told me to clean up this mess and I will".

Isn't the founder of the Amps list dead? Or that's what I
thought anyhow. He calls everyone morons, and wouldn't even
sign as Administrator this time, just left it blank. I think this
is more like the moron is on the other end. I just wonder why he's
never banned me yet? I also just double checked, it looks I was the
last to reply, and I was only wanting to know more about Chinese
tube factories. Here's all I said to provoke him;

"I'm like you, there's a bunch of other amps that are much better
candidates. Even in this case, Hsu's friend had to make
modifications
and corrections to make it boatworthy. However, I have learned a
great
bit from Hsu about the Chinese tube factories. I actually found that
very educational. I would like to talk to him about some other tubes
no longer available and who might revive them like the 6LF6. I could
sell a ton of them in the US right now".

This is the very reason why I quit posting any questions on the
list, and really quit helping. If you ask me, by him banning Rich,
he just made a martyr out of him instead of showing who's boss.

Sincerely,

Will






Yahoo! Groups Links









R L Measures, AG6K, 805.386.3734
r@..., , rlm@..., www.somis.org


Re: Hi-

craxd
 

--- In ham_amplifiers@..., R L Measures <r@...> wrote:


From: R L Measures <r@...>
Date: October 4, 2006 11:52:44 AM PDT
To: ham_amplifiers@...
Subject: Re: [ham_amplifiers] Re: Hi-

Will -- My mistake, it was on p.71 of the September, 1994 issue of
QST magazine where Tom writes: "Although VHF and UHF parasitics are
undesireable effects. and must be avoided, there is no basis in
amplifier tube theory or actual experience to support such
conclusions. They are not supported by design theory or the
experience of recognized amplifier experts in the RF amplifier
design
community that include Eimac, Siemens, ETO, Henry, and Ameritron."
Since ETO is Dick and Ameritron is Tom, Dick and Tom are
"recognized
amplifier experts", and this according to a guy who says that Ni-Cr
alloys have reverse skin effect and that the conventions of AC
circuit analysis do not apply to R/L VHF parasitic
suppressors. . . . George Grammar, W1DF, QST Technical Editor
during the 1950s. was probably turning over in his grave.
Background: Around September of 1993, I received a letter from
QST Technical Topics Column Editor Paul Pagel asking me to write
another article for QST about amplifiers. The result was "The
Nearly
Perfect Amplifier", which appeared in the January, 1994 issue of the
> magazine. The article outlined things which a perfect or nearly
amplifier would have. Examples were step-start to limit inrush-I,
T/
R, R/T switching that was Faster than that of transceivers in order
to prevent hotswitching, filament-potential adjusting potentiometer
to maximize emissive life, lower-Q VHF parasitic oscillation
suppressors to improve stability, the use of a grid fusing element,
a
glitch resistor in the HV+ lead to limit peak-I during an anomaly,
and potting the HV transformer to reduce hygroscopic absorbption and
> improve heat transfer. The article apparently lit the fuse of Tom
Rauch, W8JI, (MFJ-Ameritron) and the even shorter fuse of Dick
Ehrhorn W0ID (!) (ETO/Alpha), whereupon they apparently began
kvetching to the magazine that they should be allowed to write a
rebuttal that would be published in Technical Topics. Quite
probably
since MFJ and ETO were major advertisers in QST, this got QST's
attention and QST agreed to publish the rebuttal.
As I see it, publishing the rebuttal was the only fair thing to
do. However, to be fair, my reply to the abundance of questionable
statements made therein also needed to be aired. The problem was
that QST Editor Mark Wilson. AA2Z, refused. As a result, I launched
my Web site and published my reply to the rebuttal

so that QST subscribers could see what the QST Editor did not want
them to see.

Since you okay it : )
I relish such things.

Quote;

"The thing that gets Rich Measures in trouble is that his
writings HAVE been peer reviewed and been denounced as snake
oil by academics,
Tom Rauch an academician? -- he's never taken a class in the very
basis of RF amplifier design -- alternating current circuit
analysis.




I didn't figure he did by some of the stuff he has said. One can
tell if someone has actually been taught something, or just trying
to quote things they've heard or read from unreliable sources.
I highly doubt he's ever did any actual research either. I know
what that's like as I'm still doing it on transformers and power
supplies. I've been doing it now for about two years straight.
I'm still finding out new things that I hadn't seen in other works.




responsible engineers from every major tube
builder,
The only person from a tube mfg that he got to go along with his
dicta was his buddy Reid Brandon, the Eimac Customer Relations guy -


It would about have to be as i've read the photocopy of your
letter from Eimac.



who told QST's Paul Pagel that Eimac's Chief Specifications
Engineer,
Willis B. Foote was not authorized to tell me that gold-sputtering
from the grid was thought to be caused by a UHF oscillation
condition.




That would be a salesmans tone so as not to make ones think the
tubes were faulty.




RF design engineers from many companies ranging from
amateur manufacturers to MRI/ISM amplifier builders and
several major broadcast transmitter manufacturers.
Guffaw. The clue word here is "many" because he fails to list the
companies.

Measures'
material has all the earmarks of a "good con" ... just enough
truth to give it a patina of believability to the untrained
and impressionable".
Thanks, Will.



No problem!








This all over Tom trying to argue that a control grid could
become positive.
It can and definitely does so in a grounded-grid amplifier during
most of the negative half of the driving cycle.

No, If you remember, I did say that that was the only case.
What he was getting at was it could become positive with the
grid disconnected from ground, and if I remember, there was
another way which we both collared him on.
With air in the tube, the grid can go positive provided that the
anode is sufficiently positive to make the O^2 and N^2 atoms ionize



Positive with respect to the cathode you mean? Terman calls
it less negative, see below.

Unconnected the space charge could cause the grid to become
slightly negative or to where equilibrium is achieved between
it and the cathode. The way I read it, the ions cause the space
charge to increase from the cathode toward the grid. In the
Radio Engineers Handbook, 1st edition by Terman, on page 316,
sub-section 13 is listed; "Effect of Gas Upon Tube
Characteristics" which is quoted below;

"Very small traces of gas in vacuum tubes affect the characteristics
adversely in a number of ways as a result of the positive ions
produced in the tube by collision between the gas molocules and the
electrons flowing to the anode. The positive ions travel in the
opposite direction from the electrons, and normally end their
existence by falling into the cathode or negative control
grid. Electrons that bombard the cathode tend to destroy the
emission of thoriated-tungsten and oxide coated cathodes.
Positive ions collected by the negative grid result in grid
current, which limits the resistance that may be inserted in
series with a negative grid, and which also introduces noise.

Positive-ion currents to the grid limit the d-c resistance that may
safely be placed in series with the control grid and the cathode,
because the voltage drop that such a grid current produces across the
resistance has a polarity that makes the grid less negative than
would otherwise be the case. Thus if the tube begins to liberate
gas, with resulting positive-ion grid current, the grid becomes
less negative, thereby increasing the space current. This
increases the number of positive ions produced, and will cause
additional grid current, and still greater reduction in the
negative grid potential. If the resistance in the grid circuit
is high enough, this process can become cumulative, and in some
types of tubes can easilyresult in the destruction of the tube
as a result of excessive plate current caused from loss of grid
bias. The maximum resistance that is permissable to place in
series with the grid electrode depends upon the grid
characteristics and the method of obtaining bias. It is of the
order of several megohms in small tubes used for voltage
amplification at audio and radio frequencies. With small power
tubes, such as the output tubes of radio receivers and public
address systems, the allowable grid resistance is much less,
particularly if a fixed bias is employed in the grid-cathode
circuit, since self-bias provides an automatic protection
against excessive increase in plate current".

End Quote.







It may be less negative than the cathode, or one
might say it's more positive than the cathode, but it sure
can't be
positive with respect to ground or 0 Vdc!
Ground Is Not the reference point for grid potential, it's the
cathode. Example: If the cathode is neg. 1500v (to ground) and
the
grid is neg. 1490v (to ground), the grid potential is positive
10v.

Correct, I'm not saying that and agree, but it is all still
negative with respect to chassis ground or the 0 Vdc point.
It does not matter a whit what the grid-chassis potential is, the
only thing that locally effects the emitted electrons is the
potential Between the cathode and the grid.




Correct. However, in the way voltage is defined, it has a positive or
negative polarity, and this is measured from ground or 0 Vdc by its
definition. One side of 0 is negative, and on the other side of 0 is
positive. Since the current through the tube is from the B+ supply,
and the chassis ground is generally the B-, then by definition, the
grid is never positive when tied to the chassis or B-. However, I know
to measure this, it is measured between the cathode and grid, not the
ground and grid. That's why I always agree the same as Terman
described it, less negative.






It could never be positive in respect to it, especially if
it's tied directlly to it.
Tying the grid to the cathode is a whole nuther ballgame, Will.


I know this.




Remember him saying a grid could
become positive when being bombarded by electrons, especially
if it were disconnected from ground?
He's assuming gas ionization between the positive anode and the
floating grid. The purpose of Tom's argument is to try and explain
bursts of grid-I by a means Other than an intermittent VHF parasitic
oscillation. During the parasitics debate, trying to explain why no
gas could be found in tubes that had popped their grid fuse, he
claimed that gassy tubes can getter themselves on the way to being
tested in a high potential tester. -- no fooling.



To Toms theory, in the emortal words of John Wayne, "Not hardly".





...

Editorial -- The only kind of discussion that works well is the
wide

open kind, where there is no censor-librorum/moderator/
administrator.

It's the only way to get at the root of a matter and find the
truth.
...
In other words, he was hanging me out to dry to look like a fool
over
not letting Tom be wrong.
That's why Richard George reasoned that Tom was most likely the
unidentified Administrator/censor.

I reasoned the same myself, but still can't prove it. Someone
claimed they knew it wasn't Tom, but I'd like to see proof. If
one is ashamed to, or to scared to show who they are, they don't
need to be a moderator.
A participant in a discussion can not be the censor of the
discussion
because it would stink even more than fresh feces. .


Yes, it has stunk since someone re-appeared on Amps after several
years of absence.




Well, that was it, I started by-passing him
with direct e-mails to the members that I had in my address
book.

The rest was, well history. ; )
With Tom, The cardinal sin is neutralizing his control over
others.


He sure has his control in this moderator.
But he can't control us bailouts.



According to this nameless admin, he booted all of us out.






R L Measures, AG6K, 805.386.3734
r@..., , rlm@..., www.somis.org


Best,


Will


Re: O.T. The "other" list

GGLL
 

Well, apparently it was a spoof message, not sent by the Admin. Anyway, I left the list.

Best regards
Guillermo - LU8EYW.

GGLL escribi:

It appears that the administrator of "the other" list loose a screw. About the chinese quality of tubes and amplifiers, the thread include this message from "the administrator":
"I told you morons to stop this thread. Nothing techinical here. Am I going to have to throw you all out of here. The list founder told me to clean up this mess and I will."
I now will definitely leave that list.
Best regards
Guillermo - LU8EYW.
Yahoo! Groups Links


I hate the input network

Hsu
 

开云体育

The ?GG?linear is very popular?now, but most of them with input Pi network for matching transistor driver.
? it need at least six coils and? 12 relays or switchs and some ?adjusting work.why ?throw them off my linear amplifier?
?? The problem:if without input network,its driver will unmatched.In? negative cycle, the input impendance will becuume very big, it is a bigest problem.Even in positive cycle, there is a problem, input capacitance, so the input impendance is not "pure"?resistance,if?no much more tube in parallel.
? If we?design a GG Push-pull?amp, the problem should be solved.?The push-pull design only have?1/4 input/output?capacitance in same tube' amount.The onventional P-P design must with resonator in plate tank.
? But I think it can be replace by a wideband P-P RF transfoemer, in secondary, wen can add a Pi net work.Certainly, we can use the transformer ?adjust the proportion of primary and secondary,let input impendance to match with?the transitor driver.
??? It is a good idea?
????????? 73! Hsu
my linear amp? resonance