开云体育

An addition to my last post..

Panasonic is a "Brand Name" and good old Matsushita is the manufacturer.

At the time 1979-80, Panasonic was new to parts distribution and that
account was totally bungled by the company I worked for. They eventually
went out of business maybe 5 years after I was gone.

That account could have been worth BILLIONS alone. Now Digikey also in MN
has it obviously.

FYI: Back then old Digikey was just barely hanging on as a small time HAM
Parts manufacturer. Ron Stordahl of Digi and Old Dow-Key man, both a pair
of MN hams building stuff during the hay day of ham radio. Both did OK in
the long run for the industry. Of course Dow sold out to mega money where
DIgi is still in MN doing their thing.

BOB DD

The place I worked in college was also a huge Panasonic cap dealer.

The Panasonic caps are usually the blue ones. They make caps for quite a
number of electronic manufacturers. End up in everything.

An educated guess is Digikey received a manufacturers' overrun...

BOB DD

The first question is why would you expect the manufacturer's name to
be on the part? Does the data sheet tell you it's there?

Digi-Key stocks several parts matching that description. If you want
an exact answer, you need to supply us with the Digi-Key part number.

However, I can venture a reply....since components began getting
smaller, roughly in 1940, manufacturers have had to grapple with how
to place markings on a component with less space available. Logos
became commonplace. Today, with the standard electronic component
being 60 X 30 mils, the official mark for a manufacturer may be
nothing more than a dot of a specific color.

In looking at the manufacturer's data sheet for Digi-Key's part number
P10680-ND (One of the several digi-key part numbers that matches your
description), it becomes obvious that the manufacturer's chosen logo
is a capital letter M in a box with rounded corners.

In case you have not actually read the data sheet, here it is:



The process of engineering is to predict - create an expectation -
then measure reality and compare to the expectation, and carefully
understand why they differ, and adjust either the prediction or the
measurement process. In this case, you made a measurement (visual
inspection of the capacitor), but failed to indicate how you arrived
at your prediction (data sheet information claiming that the
manufacturer's name should be on the cap).

Gazing at a sampling of electrolytic caps I have here, about half of
them have a manufacturer's name, and half have a logo.

Z

Look for the Matsushita logo, which is a triangle with arrow points
at the apex of each corner.

They might have a three letter code or a four letter code
like MSC, MECA, etc. The "(M)" says it all, by the way.

There are billions and billions of Masushita components out there
with very obscure markings.

Hal Mandel




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

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

- We recently purchased a lot of 200, 560uF, 450v, 105?C

Matsushita-

Panasonic HV electrolytic capacitors from Digikey. The boxes

they

came in say Panasonic but the capacitors therein state only the
ratings and "6072C6(M)", but there's no named mfg. What's up

with

that?

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

- We recently purchased a lot of 200, 560uF, 450v, 105?C

Matsushita-

Panasonic HV electrolytic capacitors from Digikey. The boxes they
came in say Panasonic but the capacitors therein state only the
ratings and "6072C6(M)", but there's no named mfg. What's up with

that?


Probably since what happened after the great electrolyte espionage
scandal, they don't want any service shops pointing fingers at them
over failed caps. The only problem is, service shops buy from places
like Digi-Key. Matsushita though wasn't supposed to be affected by
this when it happened. It's either this or maybe they're sub-
contracting these out through another company, and if so I'd watch
the quality. It might pay to do some snooping around about it.

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

Best,

Will

- We recently purchased a lot of 200, 560uF, 450v, 105?C Matsushita-
Panasonic HV electrolytic capacitors from Digikey. The boxes they
came in say Panasonic but the capacitors therein state only the
ratings and "6072C6(M)", but there's no named mfg. What's up with that?

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

On Nov 20, 2006, at 5:59 PM, Phil Clements wrote:

Point of note: In the past week, both W4TV and "administrator"

have

posted multiple times....from the same IP address...using a

computer

whose NIC had the same mac address...using the same version of MS
Outlook...with the same IP connection name...from a computer

with the

same name, "laptop".

I'm sure someone who is internet-savvy can identify more clues.

I am

but a recent newcomer to this technology. In the absence of
contradictory information, it seems evident that the

administrator is

no longer unknown.

The "Administrator" was not unknown after W8JI announced why I

got

booted off of AMPS.

Perhaps the baton was passed from W8JI to W4TV when the cat got out
of the bag.

Friends helping friends. During the grate parasitics debate, Joe did a splendid job of yipping and nipping.

I consider that a good thing. I have been assured many times

over the

years by my brethren who are licensed hams, that ham radio is

not an

association of anonymous strangers. Z

Hams come in a wide variety of types. In August 1986, fourteen

postal

workers were killed and six wounded by gunshot in an Oklahoma post
office, by Patrick Sherrill, N5PS.

Hence, the term "Going Postal" was born.....

You got it, Phil.

It turns out that another Ham (W6QYI) was a principal aider and abettor in the still-unsettled case involving c. 650 altar-boys in L.A. and c. 190 priests.

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

On Nov 20, 2006, at 10:35 PM, craxd wrote:

...
Finally, the admin booted Rich off the Amps mailer and Tom seemed to
know about it before anyone else by his post. Of course afterwards,
Joe seemed to know an awful lot too by his comments! Bill Clinton
once said that "the fish rots from the head down" when speaking about
the other party. I think those very words hold true here. Either W8JI
was the admin, or he had his nose so far up the admins ass, he had
brown ring around his neck.
.

Guffaw. My guess is that Joe is likely the puppet and Tom is pulling the strings.

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

On Nov 21, 2006, at 1:26 AM, badgerscreek wrote:

--- In ham_amplifiers@..., "pentalab" <jim.thomson@...>
wrote:

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

The point here is.... by oversizing the HV fuse.... the load is
then transfered to the 100 A breaker in the 240 v main 200 A
panel.... which of course didn't blow open...... instead the
glitch R's fried themselves... !
You need well over 100 A to open a 100 A panel breaker.

RICH SEZ... Which is why I used a 40A thermal-magnetic breaker for

the 8170 amp.
...

What Rich Says may be possible its all in the detail..

Most circuit breakers have 3 current tripping curves.

Curve A, B and C

Curve A trips roughly at 3 to 5 times the current rating.

Curve B trips at 5 to 10 times rated current

Curve C trips at 10 to 14 times current rating.

You also need to study the I Squared T ratings of the breakers.

What all this indicates is that low rated breakers could handle the
current. You foolish if you rely on a breaker alone to protect your
expensive tube and other electronics. A Glitch R is advisable.

Indeed. The glitch-R protects the tube,

I have witnessed a 8171 being tuned with a pulser to 15 kw out using
a 40 amp breaker. What i do know is that if the tube flashes or
faults, or the screen supply fails the breaker will trip. With a good
glitch R its only a matter of changing a 1.5 amp screen supply fuse
and resetting the breaker.

Amen.

Operating tubes with handles is great
since the currents are so large your protection can be cheap as a 50
cent fuse, or some humble resistors driving opto couplers and relays.

Hello, Greg === In the time that I owned the 8170 / "Plywood Box"
amplifier, I went through 4 screen PS 3AG fuses. The primary of the
xfmr had the fuse.

If you using something like a grounded screen tetrode, complicated
circuit protection schemes can be dangerous and very unreliable.
Everything is floating at 1500 volts below chasis potential!

Indeed. A screw-adjustable spark gap set to c. 2000v in series with
an ohm or three puts the brakes on as needed. Another method is
sacrificial diodes: Put two 3A or better diodes in series whose
measured piv is c. 2000v total. When the potential goes above 2000v,
the diodes avalanche and short, preventing the DC-floating cathode
circuit from typically spiking to neg. 7 - 9 kV.

I was
at first skeptical using a fuse to protect the screen, but 100 or so
arcs later i am a believer! I am also a believer in using a under
rated breaker since not once have i needed to go the main fuse
breaker box to do a reset or replace the fuse. I first used high speed
semiconductor fuses, however they expensive and blow to fast for
minor things like spider or dust induced arcs.

With the Plywood Box / 8170 amp, it turned out that the principle
reason for blowing screen xfmr fuses was an intermittent parasitic
oscillation at 68MHz. Curiously, none of the amplifier experts I
consulted during the design phase mentioned this somewhat tricky
problem.

? Free, unsolicited advice for 8170, 8171, and 8281 builders:
1. Use Bruene-bridge neutralization.
2. Minimize the Q of the - unseen on the circuit diagram - 60 to 70
MHz tuned circuit between the anode and the Tune-C by using a low VHF-
Q parasite suppressor.
3. RE: Glitch-R: Use a Globar-Kanthal Type SP or another mfg's surge-
rated R whose Joule-rating is at least equal to the Joules/watt-
seconds stored in the filter C. - note - these resistors are not
cheap. As to resistance, I try to limit peak current to 200A.
4. To minimize the effect of anode-grid feedback C, and thereby
reduce the chance of parasitic osc., select a 1 to 2 kV NPO disc
ceramic cap that resonates near 70MHz with its full length leads
soldered together. Snip one of the leads off c. 5mm from the case. Solder a 10-ohm 2W or 3W MOF resistor with 10mm leads in place of the
shortened wire. Connect the RC series combo from the grid to gnd via
the shortest route on the SK-300A socket, snipping wire if needed.
5. Put 3A to 6A diodes across all meter movements.

Murphy said that if anything can possibly go wrong, it will, and
quite often at the worst possible moment. Alas, I have found this to
be pretty much true.

end

Greg

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

This cap discharge scenairo is similar to the way a CRT rejuvenator/
cleaner works. There are whiskers that form on the elements of the
electron guns, and the discharge burns them off. Looks like a little
storm of sparks when they burn off in the neck of the tube. A quick
look at the schematic for one (like a B&K, or others) would give a
good idea of how to build one for the vacuum caps, etc.

Best,

Will


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

On Nov 20, 2006, at 4:56 AM, Mike Sawyer wrote:

Now, let me ask a question of social and political importance:

Is

it possible to 'remove' the whisker by introducing and hi(er)-
voltage to the vacuum cap?

I have done this, Mike, but one must be careful not to overdo the
procedure.
To begin with, connect a 20M to 100M HV-rated resistor in

series

with the high-potential tester to seriously limit current. . .
When a vacuum-C has been in storage for a long time, it is not
unusual to find that as applied potential rises, it will
"tink" (indicating a flashover) briefly discharging the cap

several

kV below its rated peak-V. This does not mean that the cap is
feculent. By slowing raising the applied potential until the cap
tinks, Cu whiskers can be burned off, raising the cap's piv each

time

the procedure is repeated. However, at some point in the tinling
procedure, the piv will begin to DEcrease -- i. e., the procedure
becomes destructive rather than constructive. IOW, this is yet
another case where mo' is Not always mo' betta. It is my opinion

the

3 or 4 tinks is about the limit.
cheerz

...
Mike(y)
W3SLK
----- Original Message -----
From: craxd
To: ham_amplifiers@...
Sent: Monday, November 20, 2006 12:29 AM
Subject: [ham_amplifiers] Re: AC HiPot tester question

It sounds to me that Jennings wants things two different ways.

First

they say don't momentarily test a vacuum cap with DC, but it's

okay

to put one in service as a DC blocking cap, de-rated or not. From
everything I've ever read, the whisker problem is caused over

time,

not in one minute of use. A DC blocker cap could be in an amp for

a

lifetime. That's a good sales gimmick to sell hipots though. I've
never seen that warning either by Comet, or by any of the Russian
manufactured caps. If the cause is over the copper being too soft
used for the plate cups, it ought to be changed to a hard copper

or

an alloy to stop it. I can see soft copper for the bellows, but

not

the plate cups.

Thank God Rich and I didn't question the Jennings engineers on the
other list as we would have been sent another e-mail by the

unknown

admin chastizing us for ever questioning these professionals with
published papers, etc....

Best,

Will

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

On Nov 19, 2006, at 2:59 AM, pentalab wrote:

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

wrote:

...
RICH SEZ.... A 20kV rated C to block 7000V DC sounds like

over-

engineering since the actual AC potential across the blocker

is

minimal.

#### Rich... Jenning's engineers tell me when using either

fixed

glass/ceramic vac cap as a PLATE Blocker.... MIN V rating of

the

FIXED vac cap has to be a MINIMUM of 3 X No load plate V......
other wise u get "whisker's" growing on the OFC plates on the
cap..... which will REDUCE the caps V rating.

So why does the statement I quoted in the Jennings catalog on

p.4

about DC operation state otherwise?

### Ur gonna get "whisker's" anyway in plate block service for
a fixed vac cap.... so the 20 kv cap... will actually be over
time... a lot lower than 20 kv. IF u Hi-pot test a fixed vac

cap

that has been used for plate block service.... u will see it

no

longer hi pot tests to 20+ kv any more.

### other than 11m ops... I never see fixed vac caps used as

plate

blockers.

I do, Jim. Even 500pF is plenty for a DC blocker at 1.8MHz (XC =

190-

ohms) in typical amplifiers since RL is in the kilo-ohms range.

11m ops don't need much C for 11m... 100-250 pf max
is what they typ use. Their requirements are for a plate

block cap

that handles LOTS of RF... esp for 4x20's, etc.

Tom Rauch apparently knows a Ham who mistakenly used a 100pF DC
blocker in a homebrew amplifier. The amplifier produced the

expected

output from 1.8 to 28 MHz. Sometime later, when a friend was

being

shown the amplifier, he noticed that there were only twp zeros

after

the 1 on the blocker cap. When a 1000pF cap was substituted for

the

100pF cap, the output did not increase although the tuning

changed

slightly on the 1.8MHz band.
...
R L Measures, AG6K, 805.386.3734
r@..., rlm@, www.somis.org

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

I think I'd want one to act fast at the trip current it's rated at.

By the way, did you make it back home, or do they still have you
living out of your two room suite? When you get back, and you might
want to come up shopping at Harbor Freight, let me know and I'll run
down. That would be about a 1 to 1-1/2 hour drive for you I think,
about 20 minutes for me.

Best,

Will


--- In ham_amplifiers@..., "Harold Mandel" <ka1xo@...>
wrote:

-----Original Message-----
From: Harold Mandel
Sent: Monday, November 20, 2006 2:04 PM
To: ham_amplifiers@...
Subject: Hydraulic/magnetic circuit breakers



So I found a source, but haven't called them yet:
Carling Industries, Connecticut



The sell a "Series B"

available in Ultra-Short, 250 volt, 30 ampere,

panel mounted.



(860) 793 - 9281.





From reading the discussion I see people wanting to use

breakers from 30 to 100 amps on the same amplifier.



If I were building a GU-84b, 4KV @ 2 A, CCS,

with a 400 watt glitch resistor and a Tetrode Controller

with a vacuum contactor on the HV supply, is it worth

investing in a magnetic-hydraulic circuit breaker,

and at what profile, (e.g., fast, very fast, ultra fast, etc.)?



Hal Mandel

W4HBM

At the time, when all this happened, there was about 4-5 of us "in
the know" sending private e-mails back and forth. At the time, the
unknown admin had placed both Rich and myself on full moderation over
questioning W8JI's comments. I got an e-mail from the unknown admin
chastizing me over questioning Tom and what they called other
published engineers. This is in fact, a lie, as Tom was the only one
I ever questioned. The only "published" author was Terman who I
agreed with 100%! Of course W8JI's modus operandi is twisting ones
words trying to make them look like they mean something else all
together, or plainly mis-quoting an individual to try and prove his
point. When this didn't work with me, he went so low as to try and
question my education. When I told him what to do with his question,
the admin privately e-mailed me the chastizing e-mail. That was the
same e-mail he made liablous comments about Rich.

When we were privately discussing who the unknown admin might be,
W8JI's name popped up. The very next evening, about the first post
made by W8JI stated that he was not the admin as if he had heard what
was being talked about. Nobody had said this publically as yet on
Amps. I would say that someone unknowingly had spoken about the
conversation we had to another, and the other forwarded it on to
W8JI. It was either that or the guilt had built to the point, a fib
was in order, and his announcement was made. I also remember that
Joe, W4TV had a lot to say at the time to Rich, and both W4TV and
W8JI were involved in the great debate at the other list as I went
back and read it. That other list is where it first started, and then
spilled over to the Amps mailer after they jackbooted Rich off the
other.

Finally, the admin booted Rich off the Amps mailer and Tom seemed to
know about it before anyone else by his post. Of course afterwards,
Joe seemed to know an awful lot too by his comments! Bill Clinton
once said that "the fish rots from the head down" when speaking about
the other party. I think those very words hold true here. Either W8JI
was the admin, or he had his nose so far up the admins ass, he had
brown ring around his neck.

As Paul Harvey said, "... and now you know [pause] the Rest of the
Story."

Best,

Will



--- In ham_amplifiers@..., "Phil Clements" <philc@...>
wrote:

Point of note: In the past week, both W4TV and "administrator"

have

posted multiple times....from the same IP address...using a

computer

whose NIC had the same mac address...using the same version of

MS

Outlook...with the same IP connection name...from a computer

with the

same name, "laptop".

I'm sure someone who is internet-savvy can identify more clues.

I am

but a recent newcomer to this technology. In the absence of
contradictory information, it seems evident that the

administrator is

no longer unknown.

The "Administrator" was not unknown after W8JI announced why I

got

booted off of AMPS.

Perhaps the baton was passed from W8JI to W4TV when the cat got out
of the bag.

I consider that a good thing. I have been assured many times

over the

years by my brethren who are licensed hams, that ham radio is

not an

association of anonymous strangers. Z

Hams come in a wide variety of types. In August 1986, fourteen

postal

workers were killed and six wounded by gunshot in an Oklahoma

post

office, by Patrick Sherrill, N5PS.

Hence, the term "Going Postal" was born.....

(((73)))
Phil Clements, K5PC

Point of note: In the past week, both W4TV and "administrator"

have

posted multiple times....from the same IP address...using a

computer

whose NIC had the same mac address...using the same version of MS
Outlook...with the same IP connection name...from a computer

with the

same name, "laptop".

I'm sure someone who is internet-savvy can identify more clues.

I am

but a recent newcomer to this technology. In the absence of
contradictory information, it seems evident that the

administrator is

no longer unknown.

The "Administrator" was not unknown after W8JI announced why I

got

booted off of AMPS.

Perhaps the baton was passed from W8JI to W4TV when the cat got out
of the bag.

I consider that a good thing. I have been assured many times

over the

years by my brethren who are licensed hams, that ham radio is

not an

association of anonymous strangers. Z

Hams come in a wide variety of types. In August 1986, fourteen

postal

workers were killed and six wounded by gunshot in an Oklahoma

post

office, by Patrick Sherrill, N5PS.

Hence, the term "Going Postal" was born.....

(((73)))
Phil Clements, K5PC

--- In ham_amplifiers@..., Bill Turner <dezrat@...>
wrote:

ORIGINAL MESSAGE:

On Mon, 20 Nov 2006 20:51:00 -0000, "n2mg" <n2mg@...>
wrote:

The rate is 20x the current subscription rate - has been for at

least

30 years.

I paid $135 (20 x $6.75) in 1975-ish just before the rate went to
$8.25/year or $165/life.

Mike N2MG

------------ REPLY FOLLOWS ------------

I've always found it odd that the rate is not based on life
expectancy. Someone 60 should pay the same as someone 20?

Weird.

Bill, W6WRT

I jumped at the $135 when it first became available; a good move,
indeed!

I don't find it odd about the rate. A 30 year old falls off his
tower; a 60 year old lives to be 105. It averages out and encourages
longivity. I have always found it odd that I pay the same for my
size 9 shoes that a guy with size 16 pays. That's life, I guess.....

(((73)))
Phil Clements, K5PC

On Nov 20, 2006, at 4:06 PM, zerobeat40 wrote:

Thank God Rich and I didn't question the Jennings engineers on the
other list as we would have been sent another e-mail by the

unknown

admin chastizing us for ever questioning these professionals with
published papers, etc....

Best,

Will

Point of note: In the past week, both W4TV and "administrator" have
posted multiple times....from the same IP address...using a computer
whose NIC had the same mac address...using the same version of MS
Outlook...with the same IP connection name...from a computer with the
same name, "laptop".

I'm sure someone who is internet-savvy can identify more clues. I am
but a recent newcomer to this technology. In the absence of
contradictory information, it seems evident that the administrator is
no longer unknown.

The "Administrator" was not unknown after W8JI announced why I got booted off of AMPS.

I consider that a good thing. I have been assured many times over the
years by my brethren who are licensed hams, that ham radio is not an
association of anonymous strangers. Z

Hams come in a wide variety of types. In August 1986, fourteen postal workers were killed and six wounded by gunshot in an Oklahoma post office, by Patrick Sherrill, N5PS.
...
R L Measures, AG6K, 805.386.3734
r@..., rlm@..., www.somis.org

On Nov 20, 2006, at 12:38 PM, pentalab wrote:

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

RICH SEZ...Perhaps it might be a good idea to read the specs on

the 250v-rated MOV's, Jim.

### I did. And the 250 v rating is for a 250 V max rms CCS
condition.

RICH SEZ... The critical thing is: at what potential does the unit

begin to conduct current.

Depending on who makes a MOV.... clamp V is always
way higher than that.... which is why old books always said to

use twice the PIV needed for a FWB. These days it's triple the PIV

needed [at least for commercial recifier assys].

RICH SEZ...In the 8169 / Plywood Box #2 amplifier, I deliberately

used a HV rectifier safety factor of 33% based on my measurement
of the actual PIV. There has never been a failure.

### A few good spikes down the power line and the diodes WILL
fail..

Only if the amplifier is on at the time and only if the spike goes above 451 volts-pk. And, it hasn't happened in 20+ years.

..esp with only 33% more PIV....and little or no additional
protection.

No "protection" whatsoever because now I understand why.

A broadcast engineer buddy of mine told me one of the
site's he looks after had a really good spike come down the
line.... took out everything... including diodes, and the tube
itself. The spike managed to get past ALL the MOV's as well.
That's a disaster for a Broadcast station. Smoked the standby 2nd
TX as well.

### Imo... 6A10 [1 kv- 6A CCS - 400 A surge ] diodes are
so cheap anyway.... I don't see any reason not to use at least 200-
300% more PIV. 300% IS STANDARD these days.. in the commercial
world.

Wouldn't 500% be safer?

### with a safety factor of only 33%.... the diodes would fry...
LONG before any MOV cliped the spikes off.

K5JV told me that he experienced a lightning strike that blew two bolt'em-in MOVs clean out of the box and left them smoking on the deck.

...

RICH SEZ....You seem to assume that conduction for a 250v rating

begins at 251 x 1.14 volts. It does not.

### I already know that. Rich..... take a 0-277 v variac..... and
a 250 V rated MOV..... and apply >250 V on it for 1 hr...then
tell us what happens !

According to Panasonic spec, one their 250vac-rated MOVs begins to conduct current at 390v +/- 10%. This is 278v-rms +/- 10%.

.....
### The whole point here is... with successive hits... the V rating
of any MOV starts to drop... another reason we fuse em.

Agreed

### Most newer homes in Florida have giant MOV's located just below
the main 200 A service panel... connected to main Buss... via a
20-60A breaker.

### I was convinced that the huge C filter in any HV supply
would absorb any spikes/transients... they don't.

What causes the capacitors to stop storing electrons?

The PIV across
the non conducting diodes is still sky high also.

## Spikes/transients will make it's way past huge lead acid
batteries on any UPS power supplies as well as standard -54v
telco batteries. [24 x 2400 AH cells in series = 1 string... as
many as 10 strings in parallel..each cell is >500 lbs. The -54
vdc then typ feeds >100 x DC to DC supplies... fused on input
side... and the 5 vdc @ 40A output side uses a breaker. When u
see 40 A output breakers popped open after a major event
[extremely rare] makes you wonder how a spike got through layer
after layer of protection.

### Rich... you hook ur stuff up any way you want. Me... I play it
safe. I have seen way too much damage done in the last 30 yrs, to
come home and then wire stuff up mickey mouse style. Diodes are
cheap, MOV's are cheap. Correct V sized MOV's are just as cheap as
incorrectly sized MOV's. Fast fuses are just as cheap as slow
ones. Glitch R's are cheap...

Not for an 8171.

and ditto with fast HV fuses.
Putting a 2nd HV fuse between plate xfmr sec and input of FWB has
saved our bacon twice now.

240v fuses cost less than HV fuses.

### Adding some electronic plate/grid overcurrent protection is a
good idea too. On W7DS's triode board... it also has provisions
for monitoring the HV as well. When HV drops too low... amp kicks
offline... so no way to drive it with no/reduced plate V.

I'm not even gonna argue anymore about this topic... I said my
piece.

RR

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

Thank God Rich and I didn't question the Jennings engineers on the
other list as we would have been sent another e-mail by the unknown
admin chastizing us for ever questioning these professionals with
published papers, etc....

Best,

Will

Point of note: In the past week, both W4TV and "administrator" have
posted multiple times....from the same IP address...using a computer
whose NIC had the same mac address...using the same version of MS
Outlook...with the same IP connection name...from a computer with the
same name, "laptop".

I'm sure someone who is internet-savvy can identify more clues. I am
but a recent newcomer to this technology. In the absence of
contradictory information, it seems evident that the administrator is
no longer unknown.

I consider that a good thing. I have been assured many times over the
years by my brethren who are licensed hams, that ham radio is not an
association of anonymous strangers. Z

ORIGINAL MESSAGE:

On Mon, 20 Nov 2006 20:51:00 -0000, "n2mg" <n2mg@...>
wrote:

The rate is 20x the current subscription rate - has been for at least
30 years.

I paid $135 (20 x $6.75) in 1975-ish just before the rate went to
$8.25/year or $165/life.

Mike N2MG

------------ REPLY FOLLOWS ------------

I've always found it odd that the rate is not based on life
expectancy. Someone 60 should pay the same as someone 20?

Weird.

Bill, W6WRT

Here's a question. Can one still be an ARRL life member ??

The last I heard, yes.

As in.... pay XXX dollars. Im talking about today....now.

### My buddy is an ARRL lifer. I'm sure it cost him something
bizzare like a few hundred bucks... back in 1976. Thought it
like $500.00 to $750.00

The rate is 20x the current subscription rate - has been for at least
30 years.

I paid $135 (20 x $6.75) in 1975-ish just before the rate went to
$8.25/year or $165/life.

Mike N2MG

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

RICH SEZ...Perhaps it might be a good idea to read the specs on

the 250v-rated MOV's, Jim.

### I did. And the 250 v rating is for a 250 V max rms CCS
condition.

RICH SEZ... The critical thing is: at what potential does the unit

begin to conduct current.

Depending on who makes a MOV.... clamp V is always
way higher than that.... which is why old books always said to

use twice the PIV needed for a FWB. These days it's triple the PIV

needed [at least for commercial recifier assys].

RICH SEZ...In the 8169 / Plywood Box #2 amplifier, I deliberately

used a HV rectifier safety factor of 33% based on my measurement
of the actual PIV. There has never been a failure.

### A few good spikes down the power line and the diodes WILL
fail....esp with only 33% more PIV....and little or no additional
protection. A broadcast engineer buddy of mine told me one of the
site's he looks after had a really good spike come down the
line.... took out everything... including diodes, and the tube
itself. The spike managed to get past ALL the MOV's as well.
That's a disaster for a Broadcast station. Smoked the standby 2nd
TX as well.

### Imo... 6A10 [1 kv- 6A CCS - 400 A surge ] diodes are
so cheap anyway.... I don't see any reason not to use at least 200-
300% more PIV. 300% IS STANDARD these days.. in the commercial
world.

### with a safety factor of only 33%.... the diodes would fry...
LONG before any MOV cliped the spikes off.

### MOV's are just a series of "grains" inside. The series
grains will start to short out with successive hits from
transients, spikes, surges, etc. The actual V rating of the MOV
will slowly start to go down. That's why 130V rated MOV's
are normally used. A 250 v rated Mov is cutting it too fine
for folks whose line V can reach 247-250 V.

RICH SEZ....You seem to assume that conduction for a 250v rating

begins at 251 x 1.14 volts. It does not.

### I already know that. Rich..... take a 0-277 v variac..... and
a 250 V rated MOV..... and apply >250 V on it for 1 hr...then
tell us what happens !

### Check out Joslyn's website in the USA. They are the number
one maker of commercial MOV assemblies for use in commercial /
industrial environments. You won't see any 250 v rated MOV's
used on any 240 V circuits.

RICH SEZ....chortle. My guess is that Joslyn has yet to try

measuring the zener- v of a 250V rated MOV.

### These guys wrote the book on MOV's. Latest ones they make are
the fastest yet... 1 nano second. The run o mill MOV's from
Mouser etc.. are not fast. Selenium transient suppressor's are
faster than MOV's.... but won't take the high joules. Some schemes
use Selenium suppressor's in parallel with MOV's. The selenium's
clip the super fast portion of the tansient... the MOV clips the
slower portion/higher energy portion.

### The whole point here is... with successive hits... the V rating
of any MOV starts to drop... another reason we fuse em.

### Most newer homes in Florida have giant MOV's located just below
the main 200 A service panel... connected to main Buss... via a
20-60A breaker.

### I was convinced that the huge C filter in any HV supply
would absorb any spikes/transients... they don't. The PIV across
the non conducting diodes is still sky high also.

## Spikes/transients will make it's way past huge lead acid
batteries on any UPS power supplies as well as standard -54v
telco batteries. [24 x 2400 AH cells in series = 1 string... as
many as 10 strings in parallel..each cell is >500 lbs. The -54
vdc then typ feeds >100 x DC to DC supplies... fused on input
side... and the 5 vdc @ 40A output side uses a breaker. When u
see 40 A output breakers popped open after a major event
[extremely rare] makes you wonder how a spike got through layer
after layer of protection.

### Rich... you hook ur stuff up any way you want. Me... I play it
safe. I have seen way too much damage done in the last 30 yrs, to
come home and then wire stuff up mickey mouse style. Diodes are
cheap, MOV's are cheap. Correct V sized MOV's are just as cheap as
incorrectly sized MOV's. Fast fuses are just as cheap as slow
ones. Glitch R's are cheap... and ditto with fast HV fuses.
Putting a 2nd HV fuse between plate xfmr sec and input of FWB has
saved our bacon twice now.

### Adding some electronic plate/grid overcurrent protection is a
good idea too. On W7DS's triode board... it also has provisions
for monitoring the HV as well. When HV drops too low... amp kicks
offline... so no way to drive it with no/reduced plate V.

I'm not even gonna argue anymore about this topic... I said my
piece.

later.... Jim VE7RF

...

later

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