Call Search
     

New to Ham Radio?
My Profile

Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question

Operating
Contesting
DX Cluster Spots
Propagation

Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net

donate to eham
   Home   Help Search  
Pages: Prev 1 ... 8 9 10 11 12 [13]   Go Down
  Print  
Author Topic: Basic L/R VHF Parasitic Oscillation Suppressor Design  (Read 71073 times)
AG6K
Member

Posts: 1




Ignore
« Reply #180 on: October 24, 2011, 06:03:16 PM »

Quote
G3RZP
Member

Posts: 1499


View Profile Personal Message (Offline)

Ignore
   
   
RE: Basic L/R VHF Parasitic Oscillation Suppressor Design
« Reply #172 on: Today at 11:44:54 AM »
   
Reply with quoteQuote
Rich,

When you get up to these power levels  - 30 to 100kW or more, the size of the metal box is such that it becomes a cavity resonator somewhere in the lower VHF region. So coupling to it gives you a parasitic resonant circuit, and the resistor going nowhere actually is a damping coupled to the cavity.

That's why it works.

The idea that one size fits all rarely works, and the European Union and its various woes are a prime example of that.[/quote

  Peter: There is one model of Ham 2, 3-500Z amplifier that reportedly has never had a parasitic osc. with the lid scewed down on the output compartment.
Rich, ag6k
Logged
W8JI
Member

Posts: 9748


WWW

Ignore
« Reply #181 on: October 25, 2011, 05:21:29 AM »

  I was asking Tom R., but you are correct  W1QJ.    Congrats   What happens in vacuum does not propagate  well audibly.  A good way to understand Tom's agenda is to pay attention to the questions he ignores.
Rich, Ag6k

I never ignore serious questions, but I often ignore trolls in their entirety, or questions that have been asked and answered multiple times. If someone is unwilling to read or acknowledge several responses, adding one more does not help.
Logged
AG6K
Member

Posts: 1




Ignore
« Reply #182 on: October 25, 2011, 05:32:40 AM »

Quote
W8JI
Member

Posts: 7630


View Profile WWW Personal Message (Online)

Ignore
   
   
RE: Basic L/R VHF Parasitic Oscillation Suppressor Design
« Reply #181 on: Today at 05:21:29 AM »
   
Reply with quoteQuote
Quote from: AG6K on Yesterday at 05:57:24 PM
  I was asking Tom R., but you are correct  W1QJ.    Congrats   What happens in vacuum does not propagate  well audibly.  A good way to understand Tom's agenda is to pay attention to the questions he ignores.
Rich, Ag6k

I never ignore serious questions, but I often ignore trolls in their entirety, or questions that have been asked and answered multiple times. If someone is unwilling to read or acknowledge several responses, adding one more does not help.

  Apparently I need to increase the seriousness of my questions at least 10db. 
Rich, ag6k
Logged
W8JI
Member

Posts: 9748


WWW

Ignore
« Reply #183 on: October 25, 2011, 05:44:54 AM »

  Apparently I need to increase the seriousness of my questions at least 10db. 
Rich, ag6k

You do often repeat the same question many times over and over, even long after it has been answered.

For example in the gettering 572B thread, I referred you to the data sheet and even posted a link. Yet you kept repeating the same question over and over. Then a K5 (K5TR?) finally re-quoted the same data sheet link.

Maybe you just miss answers, and I wrongly assume you are being intentionally difficult. I assume once something has been  answered a few times by various people, you probably already saw it.
Logged
AG6K
Member

Posts: 1




Ignore
« Reply #184 on: October 25, 2011, 08:13:44 AM »

Quote
W8JI
Member

Posts: 7641


View Profile WWW Personal Message (Online)

Ignore
   
   
RE: Basic L/R VHF Parasitic Oscillation Suppressor Design
« Reply #183 on: Today at 05:44:54 AM »
   
Reply with quoteQuote
Quote from: AG6K on Today at 05:32:40 AM
  Apparently I need to increase the seriousness of my questions at least 10db.
Rich, ag6k

You do often repeat the same question many times over and over, even long after it has been answered.

  The problem with the 572B gettering issue is that it used to be said that absolutely running the filament for 24-hrs would getter the vacuum.   More recently it was said that zirconium gettering material was absolutely  on the graphite anode and that heating the anode would activate the zirconium gettering agent.  However, zirconium is a lustrous silvery metal - so it should show up prominently against the dark gray of the  graphite anode - but obviously no silvery metallic substance is anywhere on the 572B's anode.  This leads me to believe that one of our recognized amplifier experts has  been talking through his hat.
Rich, ag6k

Quote
For example in the gettering 572B thread, I referred you to the data sheet and even posted a link. Yet you kept repeating the same question over and over. Then a K5 (K5TR?) finally re-quoted the same data sheet link.

Maybe you just miss answers, and I wrongly assume you are being intentionally difficult. I assume once something has been  answered a few times by various people, you probably already saw it.
Logged
AG6K
Member

Posts: 1




Ignore
« Reply #185 on: October 25, 2011, 08:44:37 AM »

Quote
W8JI
Member

Posts: 7644


View Profile WWW Personal Message (Online)

Ignore
   
   
RE: Basic L/R VHF Parasitic Oscillation Suppressor Design
« Reply #171 on: Yesterday at 11:22:54 AM »
   
Reply with quoteQuote
Quote from: AG6K on Yesterday at 08:45:01 AM
    Most of the parasitics I am familiar with were on the 40m through the 15m bands,
Rich, ag6k.

That's because they are not parasitics.
Quote

  Story Adjusting:  Shortly after the 2nd QST Magazine article on VHF parasitics was published  I received a telephone call from someone identifying himself as Tom Rauch, W8JI.  He asked me if I was recording this telephone call.  I did a double-take, replied no and after a longish pause the caller began speaking about the articles in QST.  After several minutes he informed me that he had repaired over 400 Heath SB-220 amplifiers and that most of them had signs of VHF parasitic oscillation damage.  I concurred because my SB-220 had parasitic damage and I had seen several other 220s that had pitted Tune-Cap rotor plates, burned bandswitch contacts, fried grid to gnd RFCs, and gutted R-supps.  Mr. Rauch informed  me that the amplifiers he designed do not have VHF parasitics because the VHF suppressor he designed is better than Heath's suppressor.   Since I was familiar with the suppressors used on the SB-1000, SB-220 and the Al-80 I told Mr. Rauch that his suppressor design was virtually the same as Heath's.  At this point he began shouting into the telephone so loudly that when I took the telephone away from my ear, my xyl Sue, N6FEY could undertand him even though she was standing about 10-feet away from the telephone.
Rich, ag6k


You blame tank circuit voltages from mistuning, load problems, relay timing, gassy tubes, and other commonly known things on parasitics.
Logged
W1QJ
Member

Posts: 2966




Ignore
« Reply #186 on: October 25, 2011, 09:33:26 AM »

Quote
W8JI
Member

Posts: 7644


View Profile WWW Personal Message (Online)

Ignore
   
   
RE: Basic L/R VHF Parasitic Oscillation Suppressor Design
« Reply #171 on: Yesterday at 11:22:54 AM »
   
Reply with quoteQuote
Quote from: AG6K on Yesterday at 08:45:01 AM
    Most of the parasitics I am familiar with were on the 40m through the 15m bands,
Rich, ag6k.

That's because they are not parasitics.
Quote

  Story Adjusting:  Shortly after the 2nd QST Magazine article on VHF parasitics was published  I received a telephone call from someone identifying himself as Tom Rauch, W8JI.  He asked me if I was recording this telephone call.  I did a double-take, replied no and after a longish pause the caller began speaking about the articles in QST.  After several minutes he informed me that he had repaired over 400 Heath SB-220 amplifiers and that most of them had signs of VHF parasitic oscillation damage.  I concurred because my SB-220 had parasitic damage and I had seen several other 220s that had pitted Tune-Cap rotor plates, burned bandswitch contacts, fried grid to gnd RFCs, and gutted R-supps.  Mr. Rauch informed  me that the amplifiers he designed do not have VHF parasitics because the VHF suppressor he designed is better than Heath's suppressor.   Since I was familiar with the suppressors used on the SB-1000, SB-220 and the Al-80 I told Mr. Rauch that his suppressor design was virtually the same as Heath's.  At this point he began shouting into the telephone so loudly that when I took the telephone away from my ear, my xyl Sue, N6FEY could undertand him even though she was standing about 10-feet away from the telephone.
Rich, ag6k


You blame tank circuit voltages from mistuning, load problems, relay timing, gassy tubes, and other commonly known things on parasitics.


In all the years I have followed this debate this is the first time I heard this story.  I would have thought I'd have heard this one before.  It should be in the archives of "amps" if you told this one, Rich.
Logged
AG6K
Member

Posts: 1




Ignore
« Reply #187 on: October 25, 2011, 11:30:08 AM »

Quote
Quote from: AG6K on Today at 08:44:37 AM
Quote
W8JI
Member

Posts: 7644


View Profile WWW Personal Message (Online)

Ignore
   
   
RE: Basic L/R VHF Parasitic Oscillation Suppressor Design
« Reply #171 on: Yesterday at 11:22:54 AM »
   
Reply with quoteQuote
Quote from: AG6K on Yesterday at 08:45:01 AM
    Most of the parasitics I am familiar with were on the 40m through the 15m bands,
Rich, ag6k.

That's because they are not parasitics.
Quote

  Story Adjusting:  Shortly after the 2nd QST Magazine article on VHF parasitics was published  I received a telephone call from someone identifying himself as Tom Rauch, W8JI.  He asked me if I was recording this telephone call.  I did a double-take, replied no and after a longish pause the caller began speaking about the articles in QST.  After several minutes he informed me that he had repaired over 400 Heath SB-220 amplifiers and that most of them had signs of VHF parasitic oscillation damage.  I concurred because my SB-220 had parasitic damage and I had seen several other 220s that had pitted Tune-Cap rotor plates, burned bandswitch contacts, fried grid to gnd RFCs, and gutted R-supps.  Mr. Rauch informed  me that the amplifiers he designed do not have VHF parasitics because the VHF suppressor he designed is better than Heath's suppressor.   Since I was familiar with the suppressors used on the SB-1000, SB-220 and the Al-80 I told Mr. Rauch that his suppressor design was virtually the same as Heath's.  At this point he began shouting into the telephone so loudly that when I took the telephone away from my ear, my xyl Sue, N6FEY could undertand him even though she was standing about 10-feet away from the telephone.
Rich, ag6k


You blame tank circuit voltages from mistuning, load problems, relay timing, gassy tubes, and other commonly known things on parasitics.


In all the years I have followed this debate this is the first time I heard this story.  I would have thought I'd have heard this one before.  It should be in the archives of "amps" if you told this one, Rich.

  Lou == The only people who knew the details of the phone call  were Sue and some of the friends I talk to in the daytime in the 40m Combat Zone.  RE:  the Grate Debate:  There was a mention of the telephone call on 29 Oct 1996:   "> Another photo of a parasitic-arced bandswitch can be seen on page 33 of
>"Parasitics Revisited" in the October 1990 issue of QST.  The bandswitch
>was removed from a TL-922A.  After this article was published, Tom
>telephoned me at the suggestion of QST's Paul Pagel.  Tom said that such
>bandswitch arcing could be caused by "cheap coax".". 
Rich, ag6k
Logged
N2EY
Member

Posts: 5082




Ignore
« Reply #188 on: October 25, 2011, 01:57:00 PM »

The problem with the 572B gettering issue is that it used to be said that absolutely running the filament for 24-hrs would getter the vacuum. 

Who said that?

When and where did they say it?

More recently it was said that zirconium gettering material was absolutely  on the graphite anode and that heating the anode would activate the zirconium gettering agent. 

Who said that?

When and where did they say it?

However, zirconium is a lustrous silvery metal - so it should show up prominently against the dark gray of the  graphite anode - but obviously no silvery metallic substance is anywhere on the 572B's anode.

The zirconium coating on the plates of tubes such as 833A and 3-500Z is a matte gray, not "lustrous silver". The non-US-made 572Bs I've seen have plates that same color.

What does the data sheet for the 572B say?

This leads me to believe that one of our recognized amplifier experts has  been talking through his hat.

I'm no expert.

But it seems to me that when someone claims "it was said" without any reference to who, where, when or in what context, and no exact quote or link, the credibility of such claims is extremely low.

Besides, what really matters is what the 572B data sheet says. Why not simply quote it?

73 de Jim, N2EY
Logged
AG6K
Member

Posts: 1




Ignore
« Reply #189 on: October 25, 2011, 03:52:15 PM »

Quote
Quote from: AG6K on Today at 08:13:44 AM
The problem with the 572B gettering issue is that it used to be said that absolutely running the filament for 24-hrs would getter the vacuum.

Who said that?

  It was an outgrowth of the Grate Parasitics Debate but it never made sense to me because big-bangs do not come from arcs in a near vacuum.  Tom R. was a major champion and promoter of gettering in those days.  According to Tom, intermittent arcing of the Tune-
C and big-bangs in the SB-220 was absolutely due to gas in the 3-500Zs due to not properly gettering the filaments.  My position was that the extant 2600-pk-V in a SB-220 could not arc the 3500v Tune-C and that the arcing was instead due to the factory stock SB-220's intermittent parasite at approx 110MHz.  .

Quote
When and where did they say it?

Quote from: AG6K on Today at 08:13:44 AM
More recently it was said that zirconium gettering material was absolutely  on the graphite anode and that heating the anode would activate the zirconium gettering agent.

Quote
Who said that?

 I do not take notes on old wives' tales. .

Quote
When and where did they say it?

Quote from: AG6K on Today at 08:13:44 AM
However, zirconium (Zr) is a lustrous silvery metal - so it should show up prominently against the dark gray of the  graphite anode - but obviously no silvery metallic substance is anywhere on the 572B's anode.

The zirconium coating on the plates of tubes such as 833A and 3-500Z is a matte gray, not "lustrous silver". The non-US-made 572Bs I've seen have plates that same color.

  Graphite is dark gray.  Pure Zr is not. Maybe Zr gettering is a compound and not the pure element?


Quote
What does the data sheet for the 572B say?

  http://www.rfparts.com/572bprices.html  says nothing about gettering.

Quote from: AG6K on Today at 08:13:44 AM
This leads me to believe that one of our recognized amplifier experts has  been talking through his hat.

I'm no expert.

  count yourself  lucky you did not make his list.

Quote
But it seems to me that when someone claims "it was said" without any reference to who, where, when or in what context, and no exact quote or link, the credibility of such claims is extremely low.

  At the peak of the gettering frenzy it was preached far and wide to never fire up a new 3-500ZG without first very observantly gettering the filament for 24-hours.  You would of had to have been there Jim.  It reminded me of the Great Tulip Frenzy in Holland c. 1637CE.

Quote
Besides, what really matters is what the 572B data sheet says. Why not simply quote it?

  RF Parts' data sheet on the PRC 572B says nothing about gettering and China is apparently the only country where the 572 is currently mfg. 
73 de Jim, N2EY
cheers
Rich, ag6k

Logged
AG6K
Member

Posts: 1




Ignore
« Reply #190 on: October 25, 2011, 10:18:07 PM »

Rich:  When you "quote" someone, you should include the callsign or identifier of the person you are quoting so readers can backtrack to view the quote themselves.

  Other members have told me to click REPLY at the bottom.  This is the most convoluted reply system I have yet encountered Allen.
Rich, ag6k
Logged
N2EY
Member

Posts: 5082




Ignore
« Reply #191 on: October 26, 2011, 02:25:26 PM »

The problem with the 572B gettering issue is that it used to be said that absolutely running the filament for 24-hrs would getter the vacuum.

Quote
Who said that?

It was an outgrowth of the Grate Parasitics Debate but it never made sense to me because big-bangs do not come from arcs in a near vacuum.

Who actually said it?

 Tom R. was a major champion and promoter of gettering in those days.  According to Tom, intermittent arcing of the Tune-
C and big-bangs in the SB-220 was absolutely due to gas in the 3-500Zs due to not properly gettering the filaments.  My position was that the extant 2600-pk-V in a SB-220 could not arc the 3500v Tune-C and that the arcing was instead due to the factory stock SB-220's intermittent parasite at approx 110MHz.

That does not answer the question of who actually said what. Nor where or when.

Quote
When and where did they say it?

More recently it was said that zirconium gettering material was absolutely  on the graphite anode and that heating the anode would activate the zirconium gettering agent.

Again, that does not answer the question of who actually said it, nor when and where.

I do not take notes on old wives' tales. .

If you cannot clearly say who said something, when they said it, where they said it, nor provide a link to what they actually said in order to prove your claims, why should those claims get any credibility?

btw, the Svetlana 572B data sheet says that the plate has a titanium coating for gettering purposes.

73 de Jim, N2EY
Logged
W8JI
Member

Posts: 9748


WWW

Ignore
« Reply #192 on: October 26, 2011, 03:49:25 PM »

btw, the Svetlana 572B data sheet says that the plate has a titanium coating for gettering purposes.

73 de Jim, N2EY

I gave the link to him at least twice.

K5TR gave a link to him also.

Why beat a dead horse?
Logged
AG6K
Member

Posts: 1




Ignore
« Reply #193 on: October 26, 2011, 03:58:09 PM »

Quote
N2EY
Jim
   
RE: Basic L/R VHF Parasitic Oscillation Suppressor Design
« Reply #191 on: Today at 02:25:26 PM »
   
Reply with quoteQuote
Quote from: AG6K on Yesterday at 03:52:15 PM
The problem with the 572B gettering issue is that it used to be said that absolutely running the filament for 24-hrs would getter the vacuum.

Quote
Who said that?

   Tom R. as I recall.

Quote from: AG6K on Yesterday at 03:52:15 PM
It was an outgrowth of the Grate Parasitics Debate but it never made sense to me because big-bangs do not come from arcs in a near vacuum.

Who actually said it?

  One more time - see below

Quote
Quote from: AG6K on Yesterday at 03:52:15 PM
 Tom R. was a major champion and promoter of gettering in those days.  According to Tom, intermittent arcing of the Tune-
C and big-bangs in the SB-220 was absolutely due to gas in the 3-500Zs due to not properly gettering the filaments.  My position was that the extant 2600-pk-V in a SB-220 could not arc the 3500v Tune-C and that the arcing was instead due to the factory stock SB-220's intermittent parasite at approx 110MHz.

Quote
That does not answer the question of who actually said what. Nor where or when.

  alas

Quote
When and where did they say it?

  Do you know who Tom R. is?

Quote from: AG6K on Yesterday at 03:52:15 PM
More recently it was said that zirconium gettering material was absolutely  on the graphite anode and that heating the anode would activate the zirconium gettering agent.

Again, that does not answer the question of who actually said it, nor when and where.

  alas

Quote from: AG6K on Yesterday at 03:52:15 PM
I do not take notes on old wives' tales. [/quote]

Quote
f you cannot clearly say who said something, when they said it, where they said it, nor provide a link to what they actually said in order to prove your claims, why should those claims get any credibility?

  I'm pretty sure there are other old farts who remember the Rauchian gettering fad.

Quote
btw, the Svetlana 572B data sheet says that the plate has a titanium coating for gettering purposes
.

  Svetlana does not make 572Bs.   PRC 572Bs do not appear to have any coating on their graphite anodes and the RF Parts data sheet says nothing about gettering.  . Rich, ag6k

73 de Jim, N2EY[/quote]
Logged
AG6K
Member

Posts: 1




Ignore
« Reply #194 on: October 26, 2011, 04:06:02 PM »

Quote
Quote from: N2EY on Today at 02:25:26 PM
btw, the Svetlana 572B data sheet says that the plate has a titanium coating for gettering purposes.

73 de Jim, N2EY

I gave the link to him at least twice.

K5TR gave a link to him also.

Why beat a dead horse?

  Svetlana does not mfg 572Bs, they are only made in the PRC - and their data sheet says nada about gettering.  Rich, ag6k
Logged
Pages: Prev 1 ... 8 9 10 11 12 [13]   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!