Maybe one should check the design of WLW back in the day w/500KW AM
.. and reportedly they had it up to 800KW just for fun.
Just observ'en.
Andy
On 3/8/2025 12:13 PM, Jim VE7RF via
groups.io wrote:
I'm betting this will be an epic failure.? I'll put money on
it.?
BBI, in his infinite wisdom, is
documenting the....'worlds biggest 11m amplifier' on his U
tube channel. Using the 4CW-100,000E water cooled tetrode.
Teaser video.? 7 mins long.? ? ??
Here is part #1.? ? ?It's? ?2 hrs
and 27 mins long.? ? ?
I found 5 x mistakes so far.? ?This
will be an epic failure.? ?It's? good entertainment though.
20 kw of drive for 500 KW? output.?
?Being built in Victoria Texas......in a welding shop.... by
John? De Luna and BBI.? ?
Here is the detailed Eimac spec
sheet for the 4CW-100,000E? ??
IF they are gonna run it in GG, with
both screen and grid bonded to the chassis, the 500 watt grid
will burn up 1st.
If it's gonna be grid driven, well have fun, esp neutralizing
it.? ?If it's? gonna be cathode driven, like a Collins 30S1,?
have more fun.? On the 30S1, the B+ supply, screen supply, and
the bias supply are all in series, which means the screen and
bias supply have max plate current flowing through em.?
I'm gonna assume 3 phase power to run it.? ?With 500 kw
pep out,? it will suck? 800-900 kva.?
Well he did parallel 4 x 2 uf @ 40 kv oil caps for the B+
filter.? ?With 3 phase power, the raw DC from the 6 x leg
rectifier assy has 5.2 % ripple.? ? With 8 uf of filtering and
20 kv,? total energy in the 4 x caps = 1600 joules = dick on a
770 kw? DC input supply.? Any hum will be? 360 hz. (6F on 3
phase).
The tube requires? 20 gallons per minute? at no more than 70
psi...... just for 100 kw CCS anode dissipation.? My garden hose
only does? 4 gpm.? I would be worried about distilled water
purity, and resistance, and possible super heated? steam
explosions.?
100 kw of diss =? 341,000 BTU's? of heat to get rid of.? ?Do the
maths, that will require one helluva BIG air cooled? and
shrouded radiator to dump that much heat.?
Eimac also warns of an X-ray hazard, when operated > 15 kv.?
? ?The cavity needs to be lined with .020" lead sheeting.?
?
?The folks? building this amp? are in for a rude awakening.?
? They are talking about 250 kw CXR, and swinging to 500
kw....and pep output close to a megawatt.? ?When tuned for close
to a megawatt, the tank eff? with just the 250 kw CXR will be
aprx 25%.? ? Anode diss = 750 kw.? ?Tube rated for 100 kw
diss.??
Calculate the RF? current through the tank coil, and it's aprx?
225 amps.? Shit, even Kintronics doesn't make anything that
big.? ?3" tubing would run hot.? ?The RF current through the
tune and load caps is beyond horrendous.? ?205 amps through the
load cap.? 102 amps through the tune cap.? 80 amps into the TR
relay? + coax.? ?You would have to parallel 3 x Gigavac G52?
spst vac relays to handle that current. 5.7 kv peak across the
connectors, load cap, and TR relay...and coax....with a 1:1?
swr.?
Toss in sundry items like the plate block cap assy, which will
have? 100+ amps through it....... which in this case would have
to be a fixed ceramic vac cap....and this will be end up being?
the project of the decade.?
This amp would work....if they backed down on the insane power
levels.? Dunno what they are gonna use for an ant,? but if it's
a gamma matched yagi with a vac cap, they will be in for more
surprises.? ?The rotor loop will be an? engineering feat in
itself.? ?CM choke....good luck with that, not happening.?
IF they can pull it off, hats off to em.? IMO, they have bitten
off more than they can chew.?
--
"Where the Old Soo crossed the New Soo"
Duplainville, Wisconsin
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