All,

I finished coding the first portion of the long formula calculations
in imperial measurements for the Maxwell Transformer Calc. When the
results are compared to the short formula for 12 kilogauss and 60 Hz
(see pic at view one), it's just about exact. I posted another pic
(View 4) showing the results for a 220 Vac primary and the 3000 watt
transformer for any interested.

View 1;



New View 4;



Best,

Will

pentalab wrote:
<snip>

### On the bench they measure 36 pf.... bolted into the chassis... they rise to 50-55pf. IMO, it's the proximity of the lower fins to the chassis that's causing this. Bring it down another 1"... and I'm betting it will increase substantially. It would take all of 5 seconds to measure
the exact pf in the submounted case. [nothing connected to anode]

I will measure this tomorrow and report back the difference between the
measured anode to grid capacitance unmounted and sub-mounted.

In the submount case, the tube will also have to be inserted

from

below ! IE: stuff the top of the anode UP through a min

4.94"

diam hole in the chassis.

TONY SEZ.... Not in the case of a YC-156 or YC-179. It works just

fine inserting it from the top.
### whoa . If the grid ring is aprx 5" diam.... the hole in the chassis has to be a tiny bit bigger... u drop it from above... then u would need offset metal standoffs to screw to the top side of the grid ring.... up and outwards beyond the hole in chassis.... to screw to chassis ??? Still, this would leave a huge hole immediately next to the tube... and loads of air will get through... way more than if u used a SK-306 chimney ?

No. The hole in the chassis needs only to be large enough to pass the
grid ring from the top, even snuggly. Once it is passed through that
hole it mounts on a plate an inch below the chassis. That plate can be
6" square or more if you want it to be. In the case of my GS-35B mounts
I use 1/8" copper plate which is supported by a 1" length of 4" square
extruded aluminum tube that has 116 1/4" holes around its perimeter.
Since it is unlikely you will find 6" square extruded tubing, a simple
standoff can be made using 1/4" thick flat 1" wide stock forming a
square that is 6" on a side. Fill the sides with 1/4" holes and the area
of the holes exceeds the difference in the area of the hole in the
chassis and the area occupied by the ceramic of the tube. You have
virtually solid ground for the grid with only a 5" hole in the chassis
which is nearly the same diameter as the anode. The straight tube PTFE
chimney works fine. In fact, you can turn a small lip on the bottom of
the chimney and let it protrude through the hole the thickness of the
chassis plate if you want to. As you stated earlier, it's heavy enough
to stay on the chassis itself and requires no mounting at all. You slip
the chimney over the tube after it is secured with its screws from the
bottom.

TONY SEZ... I have to wonder about suspending the tube out there

in the middle of the cross. There's a bit inductance gained grid to ground by doing that.

Plus there's a significant amount of loss in the conduction of

heat away from that flange.
### Point well taken! A ring of holes would result in least inductance. With the amount of airflow available.. the grid ring is still gonna get cooled allright. Notice how JA6TAY appears to use a large copper sheet.. and puts his tube, C1/C2 cap on it ?

Yep, and many folks ignore the large current path between the tank and
the tube.

<snip>

### 3 x YC-156's is totally stupid.[11m ops have successfully done it, they are obviously not stupid... maybe we should invite a few of em to this group, they seem to have a wealth of info.... like how to use LMR-1200 as a rotor loop, what blows up, what doesn't, who makes reliable pole pigs, once removed from the oil, etc.]

LOL! Some of them ARE smart... smarter than given credit... but I am
afraid that the majority seem to demonstrate the opposite.

## I can see two of em....barely. Even then,they would gobble up chassis space. My buddy asked Eimac if they could remove the 4.94" cooler from these YC-156/YC-179's... and install the larger 7.5" diam cooler from the 3CX-15KB7... Eimac said.. "no way".

We've discussed that also but way too much trouble. Considering that it
isn't just the fins that will have to be increased in size. You'd also
need more copper in the core to get the heat out to those fins.
Unfortunately there is a practical limit beyond which more air just
doesn't do enough good to keep adding it.

### Considering the typ "200 A" service most folks have, coax, flexible coax, 7-16 Dins, baluns,etc... with 10-20 kw pep out... you have usually reached an upper practical limit. The next 3db is just too impractical... requiring a 440 lb dahl, careful layout, obscene currents, bizzare component requirements etc. Still, it could be done.... and a fun engineering challenge... doable... but very expensive. The overall logistics can quickly get out of hand. Just toss some numbers into the various spread sheets for a lark....cheap entertainment.
Later... Jim VE7RF

I've done that with my spread sheet... it's pretty amazing the amount of
current from the 240 Volt line and that's just for the plate input
power! It is that fact alone that has opened the eyes of a few to
realize they couldn't really do some things that they "talked" about doing.

You can get another 3 dB above the YC's but any more than that and you
have all the problems you've mentioned and unless one is ready for
those, it occurs at lower power levels too.

Get back to you with those measurements.

Regards, Tony W4ZT

craxd wrote:

Bill,

That is exactly the truth. When I started in repair (radio and TV),
tube sets were still around. There, you replaced parts in a chassis
with point to point wiring. Next came addition of PC boards with
tubes, and then the hybrid sets came having both tubes and solid
state devices. After that came the modules. That was easy fixes,
however the power supplies power components like resistors, etc were
still mounted on tie strips, etc. Zenith modular sets were my
favorite with the upright chassis. Magnavox had one similar.
Motorola, soon to be Quasar had the "works in a drawer". Next came
the replacable chassis. No more modules, they wanted you to change
the whole chassis out. Then it was only one large flimsy PC board. I
repaired most of these anyhow and only changed a chassis after
lightning damage. First you had a chassis and a tuner. Finally, the
one board included both. I forgot to mention that hot chassis started
about this time or a little earlier. I was selling and servicing
Philco TV's at the time for North American Phillips. Phillips bought
Philco from GTE. Then, all Phillips did was run the same TV set down
the line and put 1 of 3 name tags on them, Philco, Magnavox, or
Sylvania. About this time is when the mass marketing of TV's began by
Lowes, K-Mart, and others large chain stores. They could sell a set
at the same price as what a private dealer could buy one for. That
closed a lot of repair shops including mine. Eventually, sets got so
cheap that you could throw them away as the cost of repair was at
least 50-76% of a new set. This especially true for 19 inch TV's on
down. VCR's did the same thing too. Now you can buy a new VCR for
about $50.

All that's taught for service anymore is replacing a chassis, and
most of it is building PC's. Vacuum tube technology is not taught
anywhere I know of. After some of us older folks are gone, I wonder
who will actually be able to do real repair work anymore?

Best,

Will

--- In ham_amplifiers@... <mailto:ham_amplifiers%40yahoogroups.com>, Bill Turner <dezrat@...> wrote:

We seem to be casting a lot of blame on individuals, but I believe

the

underlying problem isn't people, it is the nature of electronic
equipment these days.

A lot of us got our start by being repairmen, and to do that kind of
work well, one must understand the fundamentals of electronics.

These

days, you either change a PC board (if it is an expensive piece of
gear), or you just throw it out and buy another. So-called
"technicians" anymore are mostly just parts changers, not real
repairmen. I don't see that changing any time in the near future.

Of course there are some real technicians around, but any more they
are working mostly at the engineering level, not the field repair
level, and there are not a lot of them because not a lot are needed.
Once the bugs are worked out of a design, you just make 'em by the
millions and toss the bad ones.

Sad but true.

Bill, W6WRT

Will,
Question? When did GTE own Philco? I've been with them (GTE/Verizon) for 43 years and I only know that they owned Sylvania.Was that before my time there. Just wondering.

Larry, W6LAR

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

The League seems to be somewhat less than serious about

thoroughly

updating and improving the Handbook. Example: In 1994 I got a
letter from the League asking me if I was interested in improving

the

Handbook. At first I laughed, but then I foolishly said yes.
Dave Newkirk, an ex-employee of the League, told me that
correcting errors made by a guru-status ARRL employee who made an
electronic mistake in a publication is virtually impossible until
well after he makes the Silent Keys column.

If I recall, I found some errors about calculating anode current, or
the terms used with it in the ARRL Handbook. It was contradicted by
the RCA Radiotron book. There was a discussion about this on the Amps
mailer at one time. Over this, I don't hold a lot of stock in some of
the published data.

If I also recall, the calculations for Pi and Pi-L nets was off and
not changed until around 1987 or 1989? I can't remember exactly what
the date was now. So the books before this are not correct. None of
them shows you step by step how to do it. The writer goes off on too
many tangents. In my opinion the text is a mess, and one is better
off consulting other books on the subject.

Should be in big
black print on page 1 of the HV pwr supply section..... or

what's

left of it. The league loves publishing books.

Selling books, Jim -- which is how the powers-that-be in Newington
get the money to Direct the so-called Directors. Here's how it
works: Directors receive varying amounts of "shaking hands money"
for going to Hamventions. Those Directors who rock the boat more
receive less shaking hands money, and Directors who rock less get
more money. It's sorta like what goes on in the RNC and the DNC.

Money has spoken for the ARRL Handbook, QST, and other publications
from the ARRL for years. One will never see correct information with
the bias caused over this.

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

Best,

Will

On Oct 29, 2006, at 6:30 AM, pentalab wrote:

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

On Oct 29, 2006, at 1:43 AM, pentalab wrote:

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

wrote:

, and replace the RF chokes with fusing resistors.

RICH SEZ... In my experiences, a suitable glitch-R in the HV+

helps prevent grid- filament shorts.

### OK... I'll bite... why does a Glitch R prevent Grid- filament
shorts on a thoriated tungsten tube ??

IMExperiences, it takes c. 11g of force for c. 30-seconds to unbend the midpoint of a 3-500Z's filament helices far enough to straighten it following an intermittent VHF parasitic oscillation. Thus, I presume that a considerable number of amperes are delivered from the HV-PS filter-C to have been able to have bent one in the first place. Limiting the peak amperes during a parasitic oscillation decreases the perpendicular bending force

### what have u got against HV fuses Rich?

RICH SEZ.... Do you carry two spare tires in your car? As I see

it, overkill is not good engineering - except perhaps on a moon
mission if I going.

### RL Drake used a .82 ohm 1 watt reistor in the B+ as a HV
fuse.... it always blows

It is not a fuse at 2500v, it was a temporary metal vapor arc that had a v-drop of c. 20v during the period when it should have been limiting current.

...

RICH SEZ....The Henry 2k-4 has a resonant-choke filter -- perfect

for 120v operation with virtually no drop in PEP out.

### Trbl is... you would have to run a new heavy duty 20-30 A
120 V line into the shack to run a Henry 2K-4.. on 120 V.

Not true. They run FB on SSB from a 120v, 15a circuit.

In
which case, you may as well run a 240V line in the 1st place...
unless u are talking about 600 w pep out on ssb.

no, 1500 pep. Resonant-choke filter DC supplies are wonderful until you have to lift the sucker.

### Why do these Henry's weigh so much.[180 lbs].. for a 1200-
1500w pep out amp???

See above. The is no free lunch, Jim.

### a 120 lb hypersil pole pig is good for 10 kw pep out...
you could run 6 x Henry's easily.

The Plywood Box amplifier used a Peter Dahl 68-pounder with a 4500va, 13-ohm secondary for 14 pep out on ssb.

...

RICH SEZ... I disagree. Inductive loads can produce 25x the

operating potential when current stops.

### What kind of inductive load are u talking about here ??

RICH SEZ.... Even electric heaters have L.

### I find this hard to believe. You may be right though... I get
a little flash when trying to interupt an electric heater.

Indeed, Jim, indeed. An o'scope will tell it like it is. The Apollo 13 incident appears to have been the result of a thermal switch that arced when it tried to open and the arc welded it's contacts closed. A $1 MOV would have prevented the problem.

RICH SEZ...An ordinary 12vDC relay's coil can produce 400v when
the EM field collapses.

### so what ?

ignore 400v?

48 V telco' relay's from the 70's would produce
an easy 1100 V. We used to use RC snubber's to quench the
arc.... then along came the infamous VRZA15 MOV.... end of
problem. BTW.... you can series MOV's for more V... and also
parallel em for more joules... or do both. You can stick em
across anything.... except breakers.

Later.... Jim VE7RF

R L Measures, AG6K, 805.386.3734

r@..., , rlm@, www.somis.org

Yahoo! Groups Links

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

On Oct 29, 2006, at 5:54 AM, pentalab wrote:

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

On Oct 29, 2006, at 2:45 AM, pentalab wrote:

--- In ham_amplifiers@..., Tony King - W4ZT <w4zt-
060920@> wrote:

Pentalab wrote:

---

Some guy in W6 land wants me to design an amp around 3 x

YC-156's in parallel, GG... low band stuff. I figure with

600w of drive.. it should do 30-36 k out.

Wow... well if one tube isn't enough... you need a BIGGER tube!

I can't imagine dealing with the problems of paralleling 3 YC-
156's. He needs a 15k or 20k!

RICH SEZ.... Paralleling 3 tubes triples C-feedback, and that is

not desirable unless one is trying to build an oscillator. The
tube that is best suited for 20k - 35k out is the 8281/4cx15000A.
200w will drive one in AB1.

### So what ?

Anecdotal sure-cures don't cut the parasitic mustard.

Just install a globar type suppressor in each anode
lead. As is, the single YC-156 runs just fine wtih NO suppressor
at all.. and that's with it .75pf of feed through C to boot.
The single 3CX-3000A7 runs just fine sans suppressor with
it's .6 pf of feedthrough C. The 3CX-6000A7 has just .28 pf of
feedthrough C. We can probably toss the suppressor on that amp as
well. At this rate, we can put globar outa business.

### 3 x YC-156's is totally stupid.[11m ops have successfully
done it, they are obviously not stupid... maybe we should

invite a few of em to this group,

RICH SEZ.... guffaw

### well maybe not too stupid. 3 x YC-156's can be had for
$1100.00 vs huge bux for a 4 x 15.[plus socket]

What is Svetlana's price for an 8281?

### These YC-156/YC-179's.. with their almost 19db of gain..

Eimac says the gain is 14.2db at 6kV.

are
the 4-1000 for the new milenium... quick, where's that pole pig ?

### I'm serious....

Serious people look at the mfg's spec sheet instead of speculating.

cheers, Jim


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

On Oct 29, 2006, at 5:29 AM, pentalab wrote:

To prove Rich's observation about caps blowin up when the eq
resistor opens.... I'm proposing a test. Using a variac.... dial
it up so +400 vdc appears across the string of 8 x caps [50 v per
cap] THEN open one resistor [the one at the cold end]... then
watch the V go up on the cap with the open resistor.... and watch the
other 7 x cap's Voltage.... drop.

This way... the cap with the open resistor should hit +400 vdc....
and no big bangs. IF this is the case... how come u never see it
mentioned in the arrl handbook/orr's books ?

The League seems to be somewhat less than serious about thoroughly updating and improving the Handbook. Example: In 1994 I got a letter from the League asking me if I was interested in improving the Handbook. At first I laughed, but then I foolishly said yes.
Dave Newkirk, an ex-employee of the League, told me that correcting errors made by a guru-status ARRL employee who made an electronic mistake in a publication is virtually impossible until well after he makes the Silent Keys column.

Should be in big
black print on page 1 of the HV pwr supply section..... or what's
left of it. The league loves publishing books.

Selling books, Jim -- which is how the powers-that-be in Newington get the money to Direct the so-called Directors. Here's how it works: Directors receive varying amounts of "shaking hands money" for going to Hamventions. Those Directors who rock the boat more receive less shaking hands money, and Directors who rock less get more money. It's sorta like what goes on in the RNC and the DNC.

... how about a super
thick hardcover one... just for linears ? .... done right this
time.... nah.. they would screw it up. YC-156... nah... u need one
of those $7500.00 Acoms.

Later... Jim VE7RF





Yahoo! Groups Links

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

ORIGINAL MESSAGE:

On Sat, 28 Oct 2006 21:02:11 -0000, "craxd" <craxd1@...>
wrote:

All that's taught for service anymore is replacing a chassis, and
most of it is building PC's. Vacuum tube technology is not taught
anywhere I know of. After some of us older folks are gone, I wonder
who will actually be able to do real repair work anymore?

Best,

Will

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

I'm sure there will be a few guys who know how to repair a tube radio
or TV but they will become a rare breed, much like people who can
repair an ancient painting or book.

Time marches on.

Bill, W6WRT

开云体育

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

On Oct 29, 2006, at 1:43 AM, pentalab wrote:

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

wrote:

, and replace the RF chokes with fusing resistors.

RICH SEZ... In my experiences, a suitable glitch-R in the HV+

helps prevent grid- filament shorts.

### OK... I'll bite... why does a Glitch R prevent Grid- filament
shorts on a thoriated tungsten tube ??

### what have u got against HV fuses Rich?

RICH SEZ.... Do you carry two spare tires in your car? As I see

it, overkill is not good engineering - except perhaps on a moon
mission if I going.

### RL Drake used a .82 ohm 1 watt reistor in the B+ as a HV
fuse.... it alwys blows b4 the built in primary ckt breakers.

RICH SEZ.... 160m is the only game in town for <1000km evening

communications when 75m gets long during the Winter months.

### agreed. 160m is an excellent band for short haul stuff.

RICH SEZ....The Henry 2k-4 has a resonant-choke filter -- perfect

for 120v operation with virtually no drop in PEP out.

### Trbl is... you would have to run a new heavy duty 20-30 A
120 V line into the shack to run a Henry 2K-4.. on 120 V. In
which case, you may as well run a 240m V line in the 1st place...
unless u are talking about 600 w pep out on ssb.


### Why do these Henry's weigh so much.[180 lbs].. for a 1200-
1500w pep out amp???

### a 120 lb hypersil pole pig is good for 10 kw pep out...
you could run 6 x Henry's easily.

...

RICH SEZ... I disagree. Inductive loads can produce 25x the

operating potential when current stops.

### What kind of inductive load are u talking about here ??

RICH SEZ.... Even electric heaters have L.

### I find this hard to believe. You may be right though... I get
a little flash when trying to interupt an electric heater.


RICH SEZ...An ordinary 12vDC relay's coil can produce 400v when
the EM field collapses.

### so what ? 48 V telco' relay's from the 70's would produce
an easy 1100 V. We used to use RC snubber's to quench the
arc.... then along came the infamous VRZA15 MOV.... end of
problem. BTW.... you can series MOV's for more V... and also
parallel em for more joules... or do both. You can stick em
across anything.... except breakers.

Later.... Jim VE7RF

R L Measures, AG6K, 805.386.3734

r@..., , rlm@, www.somis.org

--- In ham_amplifiers@..., "Mike Sawyer" <w3slk@...> wrote:

I have a RCA SBA-1K Radio-marine amplifier, (2X 3-400Z's at 2800VDC)

which will do 1KW dead carrier all day long. RCA chose to use a dual
Dow-Key coax switch with BNC connectors for the input and output to
the antenna. RCA was known to overengineer (at least still in the mid
sixties) most of their radio equipment. Good enough for them.

Mod-U-Lator,
Mike(y)
W3SLK

#### can u do... say 1 kw out FM, on 29.6 mhz... with a 2:1
swr ??? Scratch that... RG-58 is only good for 450 W on 10m..
with a flat swr. I suppose a guy could use $1.10 per ft Teflon
RG-303.

### with BNC's + RG-58U.... I think you would be in trbl on 20-
10m. The BNC works good on my 2m handheld.... which resides in
the junk box these days.

Later.... Jim VE7RF

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

On Oct 29, 2006, at 2:45 AM, pentalab wrote:

--- In ham_amplifiers@..., Tony King - W4ZT <w4zt-
060920@> wrote:

Pentalab wrote:

---

Some guy in W6 land wants me to design an amp around 3 x

YC-156's in parallel, GG... low band stuff. I figure with

600w of drive.. it should do 30-36 k out.

Wow... well if one tube isn't enough... you need a BIGGER tube!

I can't imagine dealing with the problems of paralleling 3 YC-
156's. He needs a 15k or 20k!

RICH SEZ.... Paralleling 3 tubes triples C-feedback, and that is

not desirable unless one is trying to build an oscillator. The
tube that is best suited for 20k - 35k out is the 8281/4cx15000A.
200w will drive one in AB1.

### So what ? Just install a globar type suppressor in each anode
lead. As is, the single YC-156 runs just fine wtih NO suppressor
at all.. and that's with it .75pf of feed through C to boot.
The single 3CX-3000A7 runs just fine sans suppressor with
it's .6 pf of feedthrough C. The 3CX-6000A7 has just .28 pf of
feedthrough C. We can probably toss the suppressor on that amp as
well. At this rate, we can put globar outa business.

### 3 x YC-156's is totally stupid.[11m ops have successfully
done it, they are obviously not stupid... maybe we should

invite a few of em to this group,

RICH SEZ.... guffaw

### well maybe not too stupid. 3 x YC-156's can be had for
$1100.00 vs huge bux for a 4 x 15.[plus socket]

### These YC-156/YC-179's.. with their almost 19db of gain.. are
the 4-1000 for the new milenium... quick, where's that pole pig ?

### I'm serious.... I think it would liven things up a bit... a
different perspective perhaps. When u start talking 20-35 kw
output... it's all.. 'illegal' anyway. Now don't start some
silly discussion about how 5 kw on 20m is... 'ok', but 10 kw on
11m is a 'no-no'. Rich... does a 8281 qualify as a....'Riley H
special' ? Me... I just boil oil. None of my tubes even have
handles. I asked Reid B, if they were gonna install handles on the
new YC-243... he wents nuts on me... said it would increase costs
through the roof..... so no handles for Jimbo here.

Later... Jim VE7RF

...

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

To prove Rich's observation about caps blowin up when the eq
resistor opens.... I'm proposing a test. Using a variac.... dial
it up so +400 vdc appears across the string of 8 x caps [50 v per
cap] THEN open one resistor [the one at the cold end]... then
watch the V go up on the cap with the open resistor.... and watch the
other 7 x cap's Voltage.... drop.

This way... the cap with the open resistor should hit +400 vdc....
and no big bangs. IF this is the case... how come u never see it
mentioned in the arrl handbook/orr's books ? Should be in big
black print on page 1 of the HV pwr supply section..... or what's
left of it. The league loves publishing books.... how about a super
thick hardcover one... just for linears ? .... done right this
time.... nah.. they would screw it up. YC-156... nah... u need one
of those $7500.00 Acoms.

Later... Jim VE7RF

开云体育

开云体育

On Oct 29, 2006, at 2:45 AM, pentalab wrote:

--- In ham_amplifiers@..., Tony King - W4ZT <w4zt-
060920@...> wrote:

Pentalab wrote:

---

Some guy in W6 land wants me to design an amp around 3 x

YC-156's in parallel, GG... low band stuff. I figure with 600w
of drive.. it should do 30-36 k out.

Wow... well if one tube isn't enough... you need a BIGGER tube! I

can't imagine dealing with the problems of paralleling 3 YC-156's.
He needs a 15k or 20k!

Paralleling 3 tubes triples C-feedback, and that is not desirable unless one is trying to build an oscillator. The tube that is best suited for 20k - 35k out is the 8281/4cx15000A. 200w will drive one in AB1.

### Eimac wants get this $3200 for a 3 x 10.... Svetlana wants
$2200. Eimac wants $4500 for a 3x 15.... dunno what a
3x20 goes for. Reid at Eimac tells me in a e-mail... they now
make a 3CX-20,000C7.... socketless version of a 3x20. The SK-
1320 socket that fits all the above tubes is HUGE bux.... but a
LOT less in the Svetlana version.

### 3 x YC-156's is totally stupid.[11m ops have successfully
done it, they are obviously not stupid... maybe we should invite a
few of em to this group,

guffaw

...

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

On Oct 29, 2006, at 1:43 AM, pentalab wrote:

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

, and replace the RF chokes with fusing resistors.

RICH SEZ... In my experiences, a suitable glitch-R in the HV+

helps prevent grid- filament shorts.

### agreed... when stuff "goes nuts"... the glitch will LIMIT
current..... precede the glitch with a HV fuse... and that combo

is excellent.

RICH SEZ... What failure does the HV fuse protect against with

thoriated tungsten filament tubes?

### Lemme see. 8kv /50 ohm = 160 A Ur typ 240v pri breaker is
way too slow for my liking... even magnetic hydraulic ones... with
the fastest trip curve u can get. Supplement the pri breaker with
fast fuses might work.

Fast fuses pop like popcorn in C-filter power supplies.

The point here is... when "it" goes
nuts.... I want "it" shut down ASAP... NOW ! You stuff 160 A
through a Buss 5 kv 3 A fuse [5" long sandfilled jobs]... and
they open so fast...good enough for me. Last thing I need.. or
anybody else... is having an arc welder going on inside... waiting
for the pri breaker to maybe open. Pop a HV fuse open in the
B+... and you just took the load off the caps, diodes, and plate
xfmr.

Xfmrs and diodes are adequately protected a plain-vanilla circuit breaker. Capacitors need voltage-protection, not current protection.

A 2nd HV sandfilled fuse between one leg of dahl sec...
and diode board completes the protection.

### what have u got against HV fuses Rich?

Do you carry two spare tires in your car? As I see it, overkill is not good engineering - except perhaps on a moon mission if I going.

Greatest thing
invented since sliced bread.

Come glitch time.. it's always limiting , followed
by HV fuse opening....saves all sorts of destruction...

whether

cuzed by parasitics.. or anything else.

RICH SEZ.. A friend went the Henry booth at a Hamvention and

asked one of the Henry engineers why none of the Henry 3-500Z
amplifiers currently had 160m coverage. The reply: 1.8MHz is
below the 3-500Z's low- frequency cutoff.

### LOL. Joke right ??

RICH SEZ no.

### Other than the 3+8 k ultra... I don't think any of their
amps covered 160m. They probably didn't want to have to
redesign their 3-500Z amps to handle 160m and warc bands.....
for the few additional sales it would generate .. a lot of
fellows don't operate 160m.......

160m is the only game in town for <1000km evening communications when 75m gets long during the Winter months.

OR it could be,they didn't have
the engineering "know how"... OR perhaps they actually believed a
3-500 Z wouldn't operate at such a "low freq"...

Probably all of the above, Jim. Anybody who would use a 1000A-pk mercury contactor on a 1500w amplifier is pretty obviously some kind of schlub.

...
RICH SEZ... One step-start R will not work with amplifiers that

are made for dual 120v/240v operation.

### agreed.... but who in their right mind is gonna run an amp on
120V ?? .... unless it's a single 3-500Z.. or a similar 700w
output ..or less amp.

The Henry 2k-4 has a resonant-choke filter -- perfect for 120v operation with virtually no drop in PEP out.

...

RICH SEZ... I disagree. Inductive loads can produce 25x the

operating potential when current stops.

### What kind of inductive load are u talking about here ??

Even electric heaters have L. An ordinary 12vDC relay's coil can produce 400v when the EM field collapses.

......

RICH SEZ... Most of the grid-filament shorted tubes that I have

high- potted were Eimacs.

### All eimac 3=500Z's have a MU= 130 Knock off's are

all MU=200.

RICH SEZ... Then why do RF Parts 3-500s have the same ZSAC as

Eimacs in a SB-220 or TL-922 while Amperex 3-500s exhibit a lower
ZSAC?

### IF they have the same zsac.... they have the same MU...130
IF they lower zsac... they have a mu of 200. The lower zsac
[higher mu] tubes require less bias to get the idle current
[zsac] dialled in right. Higher mu tubes should require
slightly less drive... since you have less bias to overcome.

Agreed, Jim

Later... Jim VE7RF

...end

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

Yahoo! Groups Links

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

On Oct 28, 2006, at 7:25 PM, Mike((W5UC)) & Kathy((K5MWH)) wrote:

Ok all you amplifier genei out there; how much power will a BNC connector handle at frequencies below 30 mHz?

Mike == I accidentally connected a BNC to 6kW of SSB on 1.8MHz. Nothing happened. The innards of a BNC will mate with a type N.

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

--- In ham_amplifiers@..., Tony King - W4ZT <w4zt-
060920@...> wrote:

Pentalab wrote:

---
This works the other way too. Reid at Eimac told me fellow's
will raise the tube up on a pedestal.. like a hollow piece of
aluminium thick wall pipe.... drilled and tapped on both

ends...

this then gets the anode up AWAY from the chassis.. lowering

the

anode to grid C.

TONY SEZ... Nothing you can do external will lower internal anode

to grid C. Any external effects caused by lowering the anode by an
inch will probably not impact anyone using it below 25 MHz. The
only part of the anode cooler getting closer to chassis is the
edge. There's not a large flat surface getting closer (except the
vertical).

### On the bench they measure 36 pf.... bolted into the
chassis... they rise to 50-55pf. IMO, it's the proximity of
the lower fins to the chassis that's causing this. Bring it
down another 1"... and I'm betting it will increase
substantially. It would take all of 5 seconds to measure
the exact pf in the submounted case. [nothing connected to anode]

In the submount case, the tube will also have to be inserted

from

below ! IE: stuff the top of the anode UP through a min

4.94"

diam hole in the chassis.

TONY SEZ.... Not in the case of a YC-156 or YC-179. It works just

fine inserting it from the top.

### whoa . If the grid ring is aprx 5" diam.... the hole in
the chassis has to be a tiny bit bigger... u drop it from
above... then u would need offset metal standoffs to screw to
the top side of the grid ring.... up and outwards beyond the
hole in chassis.... to screw to chassis ??? Still, this
would leave a huge hole immediately next to the tube... and loads
of air will get through... way more than if u used a SK-306
chimney ?

TONY SEZ... I have to wonder about suspending the tube out there

in the middle of the cross. There's a bit inductance gained grid to
ground by doing that.

Plus there's a significant amount of loss in the conduction of

heat away from that flange.

### Point well taken! A ring of holes would result in least
inductance. With the amount of airflow available.. the grid
ring is still gonna get cooled allright. Notice how JA6TAY
appears to use a large copper sheet.. and puts his tube, C1/C2 cap
on it ?

Some guy in W6 land wants me to design an amp around 3 x

YC-156's in parallel, GG... low band stuff. I figure with 600w
of drive.. it should do 30-36 k out.

Wow... well if one tube isn't enough... you need a BIGGER tube! I

can't imagine dealing with the problems of paralleling 3 YC-156's.
He needs a 15k or 20k!

### Eimac wants get this $3200 for a 3 x 10.... Svetlana wants
$2200. Eimac wants $4500 for a 3x 15.... dunno what a
3x20 goes for. Reid at Eimac tells me in a e-mail... they now
make a 3CX-20,000C7.... socketless version of a 3x20. The SK-
1320 socket that fits all the above tubes is HUGE bux.... but a
LOT less in the Svetlana version.

### 3 x YC-156's is totally stupid.[11m ops have successfully
done it, they are obviously not stupid... maybe we should invite a
few of em to this group, they seem to have a wealth of info.... like
how to use LMR-1200 as a rotor loop, what blows up, what
doesn't, who makes reliable pole pigs, once removed from the oil,
etc.]

## I can see two of em....barely. Even then,they would gobble
up chassis space. My buddy asked Eimac if they could remove
the 4.94" cooler from these YC-156/YC-179's... and install the
larger 7.5" diam cooler from the 3CX-15KB7... Eimac said.. "no
way".

### Considering the typ "200 A" service most folks have, coax,
flexible coax, 7-16 Dins, baluns,etc... with 10-20 kw pep out...
you have usually reached an upper practical limit. The next 3db
is just too impractical... requiring a 440 lb dahl, careful
layout, obscene currents, bizzare component requirements etc.
Still, it could be done.... and a fun engineering challenge...
doable... but very expensive. The overall logistics can quickly
get out of hand. Just toss some numbers into the various spread
sheets for a lark....cheap entertainment.

Later... Jim VE7RF

<snip>

73, Tony W4ZT

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

, and replace the RF chokes with fusing resistors.

RICH SEZ... In my experiences, a suitable glitch-R in the HV+

helps prevent grid- filament shorts.

### agreed... when stuff "goes nuts"... the glitch will LIMIT
current..... precede the glitch with a HV fuse... and that combo

is excellent.

RICH SEZ... What failure does the HV fuse protect against with

thoriated tungsten filament tubes?

### Lemme see. 8kv /50 ohm = 160 A Ur typ 240v pri breaker is
way too slow for my liking... even magnetic hydraulic ones... with
the fastest trip curve u can get. Supplement the pri breaker with
fast fuses might work. The point here is... when "it" goes
nuts.... I want "it" shut down ASAP... NOW ! You stuff 160 A
through a Buss 5 kv 3 A fuse [5" long sandfilled jobs]... and
they open so fast...good enough for me. Last thing I need.. or
anybody else... is having an arc welder going on inside... waiting
for the pri breaker to maybe open. Pop a HV fuse open in the
B+... and you just took the load off the caps, diodes, and plate
xfmr. A 2nd HV sandfilled fuse between one leg of dahl sec...
and diode board completes the protection.

### what have u got against HV fuses Rich? Greatest thing
invented since sliced bread.

Come glitch time.. it's always limiting , followed
by HV fuse opening....saves all sorts of destruction...

whether

cuzed by parasitics.. or anything else.

RICH SEZ.. A friend went the Henry booth at a Hamvention and

asked one of the Henry engineers why none of the Henry 3-500Z
amplifiers currently had 160m coverage. The reply: 1.8MHz is
below the 3-500Z's low- frequency cutoff.

### LOL. Joke right ??

RICH SEZ no.

### Other than the 3+8 k ultra... I don't think any of their
amps covered 160m. They probably didn't want to have to
redesign their 3-500Z amps to handle 160m and warc bands.....
for the few additional sales it would generate .. a lot of
fellows don't operate 160m....... OR it could be,they didn't have
the engineering "know how"... OR perhaps they actually believed a
3-500 Z wouldn't operate at such a "low freq"...

Early Henry amplifiers had a problem welding the contacts of

the power contactor that was used to switch them on and off.
Instead of doing the obvious -- adding a step-start relay and 2
step-start resistors, Henry's solution was to install an

uncheap

humungous power contactor with mercury-wetted contacts.

### You never install 2 x step start resistors..... it's total

loop

resistance we are concerned with here. Just install one

step

start resistor.. in one leg of the 240 line.

RICH SEZ... One step-start R will not work with amplifiers that

are made for dual 120v/240v operation.

### agreed.... but who in their right mind is gonna run an amp on
120V ?? .... unless it's a single 3-500Z.. or a similar 700w
output ..or less amp.

### some henry amps had manual step start. Of course some ops
can't or won't read the manual... and left the resistor in
line... and wondered why the V reg sucked.. and v under load
dive bombed....... then posted the big question "why why why"
on that other amp reflector. Read the manual.

#### > > Loads of

good contactor's out there. A standard contactor is just 2

sets of contacts.. in series... PER POLE, so u end up with no
arcing when trying to open a load off. [u split the arc into two

simultaneous arcs = zero arc].

RICH SEZ... I disagree. Inductive loads can produce 25x the

operating potential when current stops.

### What kind of inductive load are u talking about here ??
We don't have any problems shutting OFF 400 + 800A rectifiers at
the local Telco I work at. When switching from commercial AC power
to a Diesel Gen set... they use something other than contactor's...
looks like paralled silver plated "knife switches".... one group
per phase.... they wind up the motor.. wind up the big
spring....and separate the contacts real fast.{if the motor craps
out, they can still be wound up /activated via a hand crank). On
really big set ups.... they use two such assy's... one for gen
set... one for commercial power..feeding a common load buss...
instead of a SPDT set up.

### On reg contactor's... up to 1000 A.... you will see
inductive load ratings... and HP ratings. You will also see max
interupt current ratings etc. They also make some humongous
fused and alarmed MOV's for this kinda stuff.... the size of
coffee mugs.

Contactor's got it over relays every time. Not only do u split
the arc into 2 x arcs.... it opens off faster than any relay....
simply cuz of the huge initial spring tension. The flip half,
of course... is the solenoid has to develop a huge amount of
magnetism to overcome the spring tension. Once operated... u
can't pry the contacts open with anything.

### Notice on circuit breakers, they rate em in max current
interupting capability... usually in thousands of amps...
even though the breaker maybe only stamped as '50 A' . The slots
you see on the backs of some of em are... 'arc chutes'.... to
divert some of the huge back emf from inductive loads.

> >

The direct-grounding camp all reports no problems since their

mod. and swearby that solution.

### Yeah, I swear by it.... esp after 40 e-mails from other

SB-

220/221/TL-922 owners, who also swear by it. It's worth it
anyway... guranteed 22-25 watts LESS drive required. I have

yet

to hear from any of those guys about parasitic problems

either.

The guys with the TL-922's all said.. after directly

grnding the

grids to the chassis.... they could all remove the after market
nichrome suppressor's... and re-install the stock kenwood
suppressor's..... rock stable.

RICH SEZ.. The toasted bandswitch in the jpg has damage mostly where
the 10m and 15m contacts used to be.

### Key word here is "used to be"

and NO wire from any bandswitch
contacts..... just wide, silver plated strap

RICH SEZ... Round conductors exhibit uniform RF current

distribution, flat conductors don't.

### Gimme a break. I'll take my chances with say 1/4" wide CU
strap over mickey mouse 12-10ga wire any day. Strap has zip
stray uh every time. 1/4" to 3/8" wide strap is perfect
for tuned input taps.... esp the .010" to .022" thick stuff.

### I use 3/4" wide strap on 3 x 3 amps.... for main tank
coils... and 1" wide stuff for 3x6 amp.

## strap is easier to thread through a tank coil.. and back on
itself... it's thin..... won't get near adjacent turns. With
wire... you can't wrap it at all. Special clips are needed
around the tank coil material... 1st.... that will handle the
wire. This latest craze, using teflon covered wire from
bandswitch to tank taps just adds stray uh. IF the wire gets
hot... heat can't get out.... you just insulated it with a layer
of teflon! It's not the real deal.

RICH SEZ... Most of the grid-filament shorted tubes that I have

high- potted were Eimacs.

### All eimac 3=500Z's have a MU= 130 Knock off's are

all MU=200.

RICH SEZ... Then why do RF Parts 3-500s have the same ZSAC as

Eimacs in a SB-220 or TL-922 while Amperex 3-500s exhibit a lower
ZSAC?

### IF they have the same zsac.... they have the same MU...130
IF they lower zsac... they have a mu of 200. The lower zsac
[higher mu] tubes require less bias to get the idle current
[zsac] dialled in right. Higher mu tubes should require
slightly less drive... since you have less bias to overcome.


Later... Jim VE7RF

...end

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