开云体育

开云体育

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Am 23.09.2006 um 15:41 schrieb pentalab:

I couldn't resist.

I'm dying to see some beautiful pictures of all those neat things you describe... Please be so kind and put some into the photos area of this group on yahoo.

Mni tnx de Frank DG1SBG

开云体育

I couldn't resist.

To make a 40-10m choke balun for 40-10m yagi's use type 43
beads [1" OD x .5" ID x 1" long] slid over RG-393 teflon
coax. The balun is 17" long when completed [16-17 beads.]

The Z at 7 mhz is 1350 ohms. On 10/12m... power rating is
8500 watts CCS dead cxr.

For 75m it has to be 24" long [1350 ohms Z.]

For 160m, it has to be 30" long [1350 ohms Z]

And no... 500 ohms Z is NOT enough... take ur ARRL ant
book ...and toss it !

10 turns of 10" diam 213 u won't work on 75m either.... too
low a Z. Coiled up coax in a solenoid is a huge windload...
and a pain to manhandle on a tower. When using [expensive new]
393 teflon high power coax... the last thing u need is a megabuck
worth of coax to make a solenoid.

Besides.. a real linear will cook 213 u on 75m.

Type 43 is bomb proof... and cheaper than the type 77 beads
[type 77 is shorter .81" long]

Type 43 beads are still $2.00 each.... the inferior type 77
are $3.00 each. They are cheaper still... in bulk from Amidon.

You can also get em pre-made from Ken Hirschberg at Cal-Av
labs..[and also from Jay Terleski at Array Solutions].. comes
with a 7-16 DIN... and teflon coated 10 ga wires. His are
pumped with silicone glop... under pressure.. then bubbles
removed in a vac chamber. All siver soldered to boot. The
teflon wires are unique. Each layer of fine wires is reversed
in twist cw.. ccw...cw...ccw etc.

End result is... when u form the 10 ga wire.. it stays put !!
Won't spring back....slick.

You can't blow these babies up if you tried. They won't heat up
either. Best Balun ever made... period. You can pump 15
kw into em all day long.

The boys on the contest reflector finally figured out the same
thing. The typ W2DU baluns using 303 teflon coax.. and the
tiny type 75 beads would heat up with just a 500 w dead cxr on
all bands from 1.8 to 30 mhz. They switched to type 43
small beads... and the same small 303 teflon coax.[slightly
longer.. more beads] They ran the exact same test as b4.....
except 2200 watts.... zero heat !

I use type 43 for all my bifilar rods as well. [for fils of
thoriated tungsten fils] .. but that will be another story.

Later.... Jim VE7RF

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

On Sep 23, 2006, at 1:35 AM, pentalab wrote:

### These 1500-2000w amps just bore me to tears. IMO...

it's just as easy to build a big one as a small one.

Lifting an 85lb transformer is not easy for this old fart.

##### Use a cum-a-long hooked to a basement beam... or one of
those small devices used to lift small engines. Me... after
tearing the crate apart.... I slid the 253 lb Dahl straight
across from the pallet it came on, to the new RE-enforced
cabinet. I re-enforced it with a sheet of 1/4" aluminium on
top... and unistrut below...used 4.25" dolley wheels.

### Rich.... get some help....from ur helper babe... or ask Riley
H to give u a hand, the next time he stops by... for tea.

.

... since you will never read any... "how to
build a 5-15 kw linear" in any ARRL hand book / QST article.

The laugher is that W1AW had an Alpha 2, 8877 amplifier until the
ARRL sold it to because it had a habit of zapping 8877s. The
purchaser of the amplifier, QST Editor Mark Wilson, installed a

low VHF-Q parasitic suppressors and apparently put the amplifier
to good use.

### Kilobuck 8877's are about the least cost effective.. throw
away tube one can buy these days. You can buy a 3CX-3000A7 brand
new... with a 3 yr - 12,000 warranty for a paltry $50.00
more... and have it rebuilt over and over and over. Instant on
too... and does an easy 5300 watts out... with 200 w of
drive.... or for you legal limit types.... 50 w of drive will
produce 1500 w out.

### Ted Henry agreed with me... said the 8877 for HF... was a
dumb way to go...... unless available as MRI pulls.. or u got
deep pockets. Can you imagine spending 2 grand to re-tube a
2 x 8877 Alpha 77-SX ???

### Alpha's newest amp is gonna use a single 8877... no vac tune
cap... and no pin diodes ! They just don't ..'get it'

### You can buy 2 x brand new YC-243's for a tiny bit more..
[socketless version of a 6000A7 GG triode] For $2200.00 you
can get a brand new Svetlana 3CX-10K

### All as it amounts to is ... either using bigger
components.... or doing stuff like paralleling 8 x 200pf @

15 kv HEC ceramic doorknobs to make a plate block cap assy.

With one or two thousand ohms of of RL, 1600pF is not necessary

for the DC blocker cap at MF/HF.

### I have heard everything from way more [9000 pf] to
slightly less. I can't find any two engineering books that are
evenly remotely close.

### I figured for 1.8 mhz... 1600pf would do the trick. For the
high bands, the caps current rating goes way up.... thank god...
cuz the current through those caps on the high bands is just
bizzare.

#### How much do you think is needed... for say a 1500 ohm
RL @ 1.8 mhz ????

Later...... Jim VE7RF

...

cheers, Jim

R L MEASURES, AG6K. 805-386-3734
r@...

If any of you intend to series parallel Oil caps for greater
V ratings... BEWARE. I did just that with 4 x 50 uf @ 4500 V
units. These were each 12" tall x 8' wide x 4" thick. I
got em years ago from W6RR, Roger Mace... now sk.

I had one of em flash over [6900 vdc no load] . The arc
occured between the steel case and the threaded rod that
comes up outa the oil !! Even though these units had large cone
HV insulator's out the top... the weak spot is BELOW the
insulator /rubber O ring.

The fix was to FLOAT all 4 of em... both from the chassis...
and from EACH other ! I used a huge sheet of 1/4" thick HV
Red Micarta under them... and 1/8" thick sheets of micarta
BETWEEN em. End of problem. Even though mine.. and most of
these oil caps have a nice grnd lug welded to the steel case...
DON'T BOND it to the chassis. By floating all the cases... you
will RELIEVE the stress on em... they will never arc. Treat em
like lytics.

There is now an abundance of huge size 350 V / 450 V / 500V
lytics on the surplus market. 1600uf to 5200 uf. Lotsa
joules ... which is what we want.

The 1600 uf @ 450 V lytics I obtained from Fair radio yrs ago
[$5.00 each] were all measured between 1900 uf and 2000
uf. They were all 3" diam x 6" long... and used # 10 machine
screw terminals.

I mounted 20 of em horizontally [4 rows of 5].... between two
huge sheets of 3/8" thick UHMW [from the local plastic
shop] We used a 3" hole saw in a modified drill press... and
drilled out both sheets at same time.

It all fits in a nice 19" wide short rack... with front and
rear panels. The HV meter is a 0-1 ma with 10 x 2 watt, 1
meg, 2% tol series resistor's.

This is my "external cap box". I used Millen Red/ Black HV
connector's on it. IF using the Millen's.... either use
nylon mounting screws or mount em on Micarta. Both Kings and
ROWE make better HV connector's imo.

Measured C is 100 uf. I built it years ago and used 50 k,
5% tol, 25 watt wire wound's across each cap. If you build
one of these huge lytic stacks... use Rich Measure's 100 K @ 3
watt units across each lytic. For faster bleed down time...
use a PAIR of his 100K 3 watt units across EACH lytic.
With the wirewounds, I used 'L' shaped copper straps on each
screw terminal... to dissipate heat. One end of the 'L' goes
to the screw... the wire wound is screwed to the other end of
the 'L'.

With just a single 50 K resistor across each one.... HV bleeds
down slowly.. a few mins. With 100 K units.... it takes
longer.

I recently obtained cases of 2500 uf @ 450 V lytics from that
fellow in Florida. Now these newer design caps are slick...
only 2" diam x 4" long.... and a whopping 9.8 A CCS ripple
current rating. ESR is aprx 50 MILLI ohms each.

I have 72 of em.... so I'm building 3 x banks .. with 24
caps per bank. I can use 1 or 2 or all 3 banks in parallel.

To protect all this mess.... we used a BUSS HVU-3 HV sand
filled fuse [ SSON has ton's of em... so does Buss... Buss
has em in a huge variety of ratings]. These units are 13/16"
diam on the ends... and fit a standard 3/4" fuse clip snugly.
I used the 3/4" from SSON that have end retainers on em... so
once inserted, there is NO way they can migrate out.. esp when
mounted vertically.

The surplus HV fuses from SSON are rated at 3 A CCS.. and
are sandfilled. $3.50 each... in bulk. The SSON units are
glass bodied.... the newer ones from Buss are Ceramic bodied...
other wise, they are identical. The 5" long HV fuses are
rated at 5 kv AC RMS.... and work at 8 kv DC no sweat.
They also make 10" long fuses... rated at 10 kv AC RMS / 16 kv
DC.

I install ONE of these HV fuses... in ONE leg.... between the
SECONDARY of the Dahl plate xfmr and the FWB diodes. The
2nd HV fuse goes BETWEEN the B+ output of the lytics and the
HV "Glitch Resistor's"

If something ever shorts out in the lytic banks.. the 1st
HV fuse between sec of plate xfmr and HV diodes will save
the diodes every time. With fault current... they blow
REALLY fast.

The 2nd HV fuse, located in the B+ line is always located
BEFORE the glitch Resistor... never after. IF u flipped em
around... and something happened to the glitch R [arc, dust,
etc] the fault current from the lytics could easily damage /
finish off the glitch R assy.



The "Glitch Resistor" for 2.5 to 3.0 A of dc plate
current can be built a couple of ways. My buddy used 2 x
paralleled 100 ohm @ 225 watt wire wound resistor's. A fan is
used on em to keep things cool at all times. With 3 A
keydown... diss is a whopping 450 watts ! On ssb/ cw... it's
only 1/4 of that... or 112 watts. [66 watts per resistor]

The 2nd method employed uses 4 x 200 ohm 275 watt globars...
each 1" diam x 12" long. I had loads of these older, 60's
vintage globars.... TYPE CX. BEWARE, the older CX type
globars are NOT glass bodied.. and are NOT suitable for oil
immersion. Since I couldn't use em for a QRO dummy load... they
make perfect... "glitch resistor's ".

On my buddy's latest project [I designed it, he built it],
while ironing out some bugs... One or both HV fuses opened up a
few times. The paralled 100 ohm-225 watt wirewound's didn't
flinch. The surge current is limited to aprx 158 A..... which
will blow a 3 A rated fuse in <2 msecs. The glitch R and
the C filter will also form a 'RC' time constant. Without a
glitch R... the current from the bank(s) of caps is HUGE...
only limited by the ESR of the 20-30 lytics... and the ESR of
the plate choke(s) 1.25 ohms + 1.2 ohms.


I always use 6A1O diodes... rated at 6 A CCS @ 1 kv PIV...
400 A surge. These babies are exactly double the diam of a
1N5408. They will drop right in where a 1N5408 once stood.
Dahl figured this one out too... and makes all his diode
assy's from 6A1O's. I looked at HV diodes at 8-10-12 A
ratings.... and all of em had LESS surge capability than a
6A10... and all of em required a heatsink.

The 6A1O's are used every where.... from meter protection to
series strings of em... used for BIAS. [tapped with a 20 x
position rotary switch....slickest thing yet]

Don't mess with .01uf disc caps and resistor's across each
diode... waste of time/ money /effort/SPACE. The "IN" way of
building strings of HV diodes is to use ... no load plate
voltage x 3. IOW... for a 7900 V supply... use 24 diodes
per EACH of the 4 legs in a FWB.

Now both Dahl and other's use the "ultimate" in diode
protection. They parallel a 510 v MOV across each diode.
[510LA40A.. available from Mouser, Digi-Key] I also use a 275
V bolt down MOV across the plate xfmr PRIMARY [Movistar,
available from Dahl]... and 130 V bolt down MOV's ... between
each hot leg and neutral/grnd. [available from Mouser/Digi-key]

Some will even install 6 x 1000 v [in series] MOV's across the
plate xfmr sec.

IMO... the huge banks of lytics will "swallow" any
transients, spikes,surges, that manage to get through all of
that. The lytics will look like a low Z short to any higher
V spikes, etc.

Of course... this mess of lytics has to be step started...
properly. We use a 0-30 delay timer.... the type that comes
in a 8 pin octal base... and use the mating flange mount
socket [no holes required for the mating socket... you can
flush mount em to anything] These delay units all use a DPDT
mech relay with 10 A CCS contacts. I get mine with a 120
vac coil. One 1/2 of the DPDT contacts activate the step
start contactor. You can use the other 1/2 of the DPDT
contacts to turn on a NEON.... or close the key line to the
linear..[via a pair of RCA connector's.] This way... the big
amp can't be keyed UNTIL the step start cycle has been
completed. On our step start contactor's that use 220/240v
windings.... both halves of the DPDT relay inside the delay unit
must be used. Fortunately.... those contactor's had AUX
contacts... and the AUX contacts can easily be used to close
the key line to the big amp + turn ON a neon.

The Neon can be used as a visual to let one know that the step
start conatctor /TD relay has operated.

We use 2 x paralled 50 ohm 100 W resistors for the step
start resistor assy. They can be either metal finned bolt
down units... OR wire wounds. If one ever opened up.... the 2nd
one is the back up. If a single resistor was used... and opened
up.... you could shunt a wide open !

The step start assy [25 ohms] is inserted in ONE LEG only of
the primary of the plate xfmr. 50 ohms is too much
resistance... and will produce a bigger current surge when
shunted. Install a 0-50 A AC ammeter or a 0-100A in one leg of
the 240 V primary.... you will get an eye opener ! The 50 A
and bigger AC ammeter's use current xfmr's.... which simply go
around one of the big 120 v hot conductor's. Small 18 ga
wire is then used between the actual meter movement...and the
current xfmr.

Now here's the kicker. Joules [watt seconds] goes up to the
SQUARE of the voltage! When a 8 kv pwr supply is charged up to
4 kv... the caps are only ONE QUARTER charged.. and have 1/4 the
energy of a fully charged cap. The same caps charged up to
5656 volts is only ONE HALF charged up !!

The trick here is to get the HV up as HIGH as you can... BEFORE
shunting out the step start resistor. This implies NOT
sucking huge amounts of bleeder current. Also BEWARE... all
these Dahl / Pole pig plate xfmr's typ suck 1.4 to 1.8
Amps of ac magnetizing current on their 240 v primaries.....
even with NOTHING connected to the HV secondary !! [The
magnetizing current will always be flowing through the step
start resistor... until it's shunted] .

We typ set the TD delay for 14-20 seconds... with 'typ' 100-135
uf C input HV supplies. And longer with 200-300 uf supplies.

34 uf will typ give you aprx 3% ripple. [6900 V @ 3 A]
100 uf will give you 1 % ripple. Ripple is one thing....
dynamic regulation is another [as opposed to static
regulation] . To get good dynamic regulation on a FWB C input
HV supply.... you want to shoot for 1% or less ripple.

These Dahl 253 lb xfmr's I use have a .08 dc ohm primary...
and a 8.2 dc ohm secondary ! My 10 kva Hypersil pole pigs typ
have 16-18 ohms of sec dc resistance.

Dahl tells me there is NO problem whatsoever using 150-300 uf
C input filters with his xfmr's.

If modifying a 3 pole contactor as one big SPST-DM contactor...
after paralleling the 3 contacts on each side.... you go in on one
corner... and exit diagonally. [enter top left... exit bottom
right] This will distribute the current evenly. This trick
is also used on paralled doorknobs, diodes, bandswitch wafers,
breakers, broadcast caps, etc.

On these latest bunch of 135 A rated 3 pole contactors... we
paralled all 3 poles with just aluminium 1" x 1" x 1/8"
thick 6061-T6 angle stock. This also makes it EASY to
terminate the 2 ga wire used [and also 3 x ought] Also makes
it easy to simply bolt two angles together... when the output
of one contactor is feeding the input of the step start
contactor. One modified contactor is installed in each hot
leg. The 135 A rating looked a little flaky to me... and we had
plenty of contactor's... so instead of 2... we used 3 x modified
ones. I also would suggest silver plating the contacts
with 'cool amp'... available from the cool-amp co... in Ore. I
use that stuff to silver plate everything from contacts to
tank coils to loads of copper strap. Use latex/vinal gloves..
and use ur fingers to rub it in. Contact resistance will drop
to zero every time. It works EXTREMELY well... so does 'conducto
lube'... used on sliding contacts.... pure silver in grease.

Sri for the diatribe. Sorry for boring anybody.

Later... Jim VE7RF

On Sep 23, 2006, at 1:35 AM, pentalab wrote:

--- In ham_amplifiers@..., PA3DUV <pa3duv@...> wrote:

Great info Jim!
NOW we're talking amplifiers ;-)

This yahoo group has the possibility of posting pictures, files and

the like. Some pics of your "QRP" amps (They also make the usual 10
kw 5 kw.. 2.5 kw qrp slugs.) would be very much appreciated.

Thanks again for the very interesting contributions!

Cheers, Dick
PA3DUV

### Tnx Dick..... As soon as I can figure out this pix posting
deal... We will try and get some pix up.

### Just to set the record straight. I design this QRO stuff
[including everything downstream like baluns, LC networks for
stacked arrays, etc, for ... "clients" [who will remain
nameless for obvious reasons]

### IMO.... I could care less how one gets their ERP. 1500w
into stacked yagi's is... "OK".... but 5 kw into a dipole is
a "no-no" ..gimme a break !

### These 1500-2000w amps just bore me to tears. IMO... it's
just as easy to build a big one as a small one.

Lifting an 85lb transformer is not easy for this old fart.

To me, it's an
engineering challenge.

Indeed.

... since you will never read any... "how to
build a 5-15 kw linear" in any ARRL hand book / QST article.

The laugher is that W1AW had an Alpha 2, 8877 amplifier until the ARRL sold it to because it had a habit of zapping 8877s. The purchaser of the amplifier, QST Editor Mark Wilson, installed a low VHF-Q parasitic suppressors and apparently put the amplifier to good use.

### When AES / RF Parts / Coaxial Dynamics tell me they
sell 10 kw slugs like popcorn.... it's blatantly obvious this
QRO scenario is, and always has been.. alive and well.

### Eimac tells me their is this... "secret world wide
underground network of QRO amp bulders ".... so secret.. they
don't even know each other !!

### For a laff... check out JA6TAY's site. He doesn't mess about.


### Well, the cat's out of the bag now ! I fully intend to post
as much of these "trade secrets" as I can. None of it is
rocket science really.

Amen to that.

It starts off as an engineering
problem... reverts to a... "sizing issue" then back to an
engineering issue.

### All as it amounts to is ... either using bigger
components.... or doing stuff like paralleling 8 x 200pf @ 15
kv HEC ceramic doorknobs to make a plate block cap assy.

With one or two thousand ohms of of RL, 1600pF is not necessary for the DC blocker cap at MF/HF.

...

cheers, Jim

R L MEASURES, AG6K. 805-386-3734
r@...

All,

I started editing the page on transformers at Wikipedia at 6:00 PM
this evening, and it is now 4:30 AM in the morning. I corrected a few
errors from others plus added a complete section on steel used in
transformers. I also added more in the formulas concerning designing
transformers using the square inch measurement for the core. In other
words, I showed the converted metric to inch formulas. I also showed
references to any books I used throughout the page. Below is the links
on some of the sections I corrected, modified, or wrote new.








Transformer#Operation_at_different_frequencies




Transformer#Electrical_Silicon_Steel_Types









That's about it folks, I'm tired and off to bed! Hopefully, some might
add some additional knowledge about RF transformers as it's kind of
lacking (IE ferrite types, powdered iron types, their use, etc).

73,

Will

--- In ham_amplifiers@..., PA3DUV <pa3duv@...> wrote:

Great info Jim!
NOW we're talking amplifiers ;-)

This yahoo group has the possibility of posting pictures, files and

the like. Some pics of your "QRP" amps (They also make the usual 10
kw 5 kw.. 2.5 kw qrp slugs.) would be very much appreciated.

Thanks again for the very interesting contributions!

Cheers, Dick
PA3DUV

### Tnx Dick..... As soon as I can figure out this pix posting
deal... We will try and get some pix up.

### Just to set the record straight. I design this QRO stuff
[including everything downstream like baluns, LC networks for
stacked arrays, etc, for ... "clients" [who will remain
nameless for obvious reasons]

### IMO.... I could care less how one gets their ERP. 1500w
into stacked yagi's is... "OK".... but 5 kw into a dipole is
a "no-no" ..gimme a break !

### These 1500-2000w amps just bore me to tears. IMO... it's
just as easy to build a big one as a small one. To me, it's an
engineering challenge.... since you will never read any... "how to
build a 5-15 kw linear" in any ARRL hand book / QST article.

### When AES / RF Parts / Coaxial Dynamics tell me they
sell 10 kw slugs like popcorn.... it's blatantly obvious this
QRO scenario is, and always has been.. alive and well.

### Eimac tells me their is this... "secret world wide
underground network of QRO amp bulders ".... so secret.. they
don't even know each other !!

### For a laff... check out JA6TAY's site. He doesn't mess about.


### Well, the cat's out of the bag now ! I fully intend to post
as much of these "trade secrets" as I can. None of it is
rocket science really. It starts off as an engineering
problem... reverts to a... "sizing issue" then back to an
engineering issue.

### All as it amounts to is ... either using bigger
components.... or doing stuff like paralleling 8 x 200pf @ 15
kv HEC ceramic doorknobs to make a plate block cap assy.

### heck.... rolls of 3/8" and 1/2" copper tubing is dirt
cheap at home depot or any other hardware store. Buy it by the
foot... or buy the entire roll.

### My buddy saw hundreds of these brand new 135 A 3 phase
contactor's on e-bay... dirt cheap. We paralled all 3 poles
together.. to make one big 400 A SPST-DM contactor.... and stuck
one such assy in each leg of the 240 V [single phase] line. A
3rd such contactor assy was used for the step start.

### BTW... the coils on those contactor's were rated at 220 V.
My electrician buddy told me to run em on 240 V... without any
drop resistor ! They rate em at 220 V... simply cuz it's a mid
point between 208 V... and 240 V... and will work on all 3 x
voltages nicely. They even came with 4 x complete sets of
AUX contacts.

### a buddy of mine in Ohio has access to dozens of pole pigs...
in various KVA sizes.... with or without the oil.

### 7-16 DIN chassis connector's are starting to show up dirt
cheap on the surplus market. Best and most practical QRO
connector ever made.... originally designed by the german Military
in the mid 60's.... now all the cell ph co's use em.

### There are TWO connector's you can always get for any
coax... type N and 7-16 DIN. You just can't blow up the huge
7mm center conductor on a DIN [.284" ! ] They are only 1.25"
square to boot... not much bigger than a SO-239 / Type N.

Later.... Jim VE7RF

开云体育

--- In ham_amplifiers@..., "Peter Voelpel" <df3kv@...>
wrote:

Hi Jim,

I prefer that my GG amps cannot run in too high dissipation at

full

drive. They should have no problem when the antenna gets lost...

73
Peter

### Peter, et all

### I had an engineer buddy of mine cook up a high reflected
power shut down circuit for me. My buddy got a hold of a
ton of Bird single line sections. He joined two of em
together with some brass rod and soldered the outside flanges...
to fabricate a "double line section".

### He made two such assemblies. We installed one on the
input of the amp... and the 2nd one on the output. [4 x slugs
installed]

### Since the big amp is remoted 30' away from the shack.....
we had to be able to read all 4 x line sections in BOTH
locations. My engineer buddy designed a peak reading board that
would work with all 4 x line sections.... and continuously
monitor the PEP reflected power from the ant [line section # 4 ]

### Only one bird 30 ua meter is used in each location.... and
either end can be switched independently to any of the 4 x
line sections. He used line drivers at the amp end.. to drive
the box in the shack.

### The high PEP reflected power threshold is fully
adjustable... and in this case was set to 1 kw. When the
threshold is exceeded.... a minature dpdt relay operates [ in <2
msecs] and one set of contacts applies -10 vdc to the ALC
jack of the Yaesu MK-V.... shutting it down asap !!

### The 2nd set of conatcts activates a 2nd, identical relay
[also in < 2 msecs]

### This 2nd DPDT relay opens up the key line to both the IPA
[ intermediate pwr amp] and also the 12 kw amp. The
circuit latches.... and lights a red led. A spring loaded
push button resets the circuit . [AFTER you find out why the
high swr condition occured]

### Since the 2 x minature relay's are sequenced.... the ALC
shut down on the xcvr occurs 1st.... followed by kicking BOTH
amps off line ! NO Hot switching!

### To key both amps.... I used a PAIR of P+B opto
isolators.... they run on +13.8 vdc @ 10 ma each.
The "electronic TX ground" from pin 2 of the MK-V's band
data jack supplies the grnd to both opto's on TX.

### The output side of each opto is rated at 200 Vdc @ 1 A
CCS. They also have 4 kv isolation between input and output...
and operate in under 100 microseconds. Cheap too.

### We used +120 vdc to operate all 4 x vac relays in the big
amp. [speed up circuit, with a pair of dropping resistors]

### The high swr circuit could have been configured to open
off the INPUT to both opto's instead.. of the Opto outputs. Moot
point.

## I had my engineer buddy also include a short 12-14 msec
delay... used in conjunction with the yaesu "TX inhibit lead"
[used on both the 1000-D... plane MP.... MK-V /field.

## BOTH amps are keyed NOW.... after 10-14 msecs... TX
inhibit is removed... allowing full power from the Yaesu MK-V.

### This delay ensures the vac relays won't hotswitch on TX...
even though all 4 x are sped up.... we are using RJ1A's on the
input side [one for drive RF... the 2nd RJ1A shorts out the
100k resistor to remove the cutoff bias. We paralled a pair
of larger, slower vac relays on the output 10 kw side.

### We didn't want a situation where input relays operated
1st... drive applied to cathode... and no ant connected ...yet !!

### This delay circuit is for SSB / FM /AM

### In the MK-V menu.... on CW only.,... you can delay the RF
by 0-30 msecs [ digital delay... NOTHING gets truncated
either] ... and still key the amps in real time... NOW. It
needs to be set between 10-30 msecs.

## The above T/R scheme is super fast vox cw/ ssb /fm /am.
Due to the 'slower' larger vac relays on the 12 kw output
side....qsk is not recomended.

### If anybody is interested.... the high swr circuit will be
made available down the road... along with the rest of the
schematics. It's saved everyones bacon a few times so far...
works slick... and works on any bird line section / slug size.

Later......... Jim VE7RF

Gents

This may well be old news to some... but Coaxial Dynamics makes
a 25 kw slug.[2-30 mhz].. for a standard 7/8" line
section....cheap.
They also make the usual 10 kw 5 kw.. 2.5 kw qrp slugs.

It's Not on their website.. nor catalog... but has been around for
years. I'll dig up the model number and post it in a few days.

Fits the Bird 7/8" line sections too !

The 7/8" line sections all have a huge 3/8" inner conductor
tube running down the middle..... where they then neck it down
to the small diam... to take the QC [quick connector's].

They also make 7-16 DIN QC connector's [male or female] for
both the 7/8" + 1 5/8" line sections. You can also get
7/8" EIA flange connector's as QC connector's. Any QC
connector will fit either a 7/8" line section OR a 1 5/8" line
section. The 1 5/8" line section requires an adaptor plate...
in order to accept the QC connectors.

My buddy in Ohio tells me you can also get 50 kw 2-30 mhz
slugs... but didn't say what size line section it was designed
for.

later...... Jim VE7RF

--- In ham_amplifiers@..., "Peter Voelpel" <df3kv@...>
wrote:

Hi Jim,

I use heatresistant glass cylinders I get made locally and also

use

round teflon covers as you, thats works very well.
All my blowers are made by EBM.
I do not like to boost a tubes rating, I rather prefer then to use

a

bigger one.
I prefer that my GG amps cannot run in too high dissipation at

full

drive. They should have no problem when the antenna gets lost...

### Partially agreed. ..BUT the 3CX-6000A7 is rated at 3.5 A
of plate current CCS. [7 kv under load] .

## as is.... with 2.5 A of plate current @ aprx 6900 V under
load.... DC input is 17.25 kw....... output is 11.5 kw. Anode
diss is 5.75 kw. At 6kw of anode diss.... lower anode
seal [ where the anode meets the ceramic] will be 225 Deg
C !

### I don't like running tubes anywhere near their max
anode diss. The saving grace here is ssb/cw............ the
duty cycle is WAY down. Plus Eimac's air flow specs are
based on a 50 deg C [121 deg F] intake temp... which it's not.

### The point here is.... one would HAVE to increase the anode
diss with more airflow.... in order to operate with 3 - 3.5 A
of plate current.

### Eimac also makes an industrial heater tube.... 3CX-10,000D
with a real small anode... 6.4" diam. I phoned em up.....
they just blew more air through it to get the 10 kw anode diss !


### also note the Eimac 3CX-10,000A7 and also the 3CX-15,000A7
have IDENTICAL physical dimensions in every regard.
What's the diff ??? They just blow more air through the 15K...
that's it.

### Both the 3CX-2500 and the 3CX-3000A7 have IDENTICAL
dimensions/weights. BOTH are rated at 4000 watts of anode
diss... CCS ! Eimac tells me the 2500 was origionally
2.5 kw anode diss.... then they upped the airflow....... ditto
with the 3000A7.



### The 6000A7 is one of the easiset to cool [ and to increase
the anode diss if needed/wanted] . Reason is.... the ceramic
stem is real small diam compared to a YC-156.. 10K, 5K. With
it's 6.125" OD cooler..... you end up with a HUGE fin area
underneath.

## To really utilize this huge fin area underneath... it's gotta
be able to breath right........... and that means the AREA of
the holes /slots in the chassis should be at least the same or
bigger, than the underneath fin AREA. And that means NO
straight up/down chimneys can be used......... hence the 9"
square box we used.

### The Eimac 10,000 chimney is a virtual straight up and down
affair.... and chokes off the airflow from the chassis.

### When I see a 5 HP... 3 phase 208V blower motor for a
pair of 3CX-15,000A7'S...... it makes me gag.

### Compare the pressure requirements of a YC-156 [or a 4CX-
5000] vs a 3CX-6000A7... you will get the idea. [compare em at
the SAME 50 deg C inlet air temp]

Jim VE7RF

73
Peter


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

For an experiment, I remember W7IUV had fabricated a

fiberglass

box around his YC-156.. for a chimney.

We tried the same trick... except the vertical sidewalls

were

made from wood... about 9" square... top was also made

from

wood.... and the original chimney was placed in a groove..

on

top of this wooden affair. Now we could increase the

hole

sizes on the chassis.

The result was a huge improvement! Intead of the original

205

cfm... we are now getting an easy 320 cfm [using a

Dayton

5C508 dual speed, capacitor start blower].

On Sep 22, 2006, at 1:54 PM, pentalab wrote:

--- In ham_amplifiers@..., "Peter Voelpel" <df3kv@...>
wrote:

Jim,

Grid dissipation is measured by ohms law, grid voltage by grid
current.
Since the grid is at ground, you just measure the cathode voltage

with

a scope.

### whoa. Are you saying RF cathode V x DC grid current
= grid diss ????

That's pretty much what Care and Feeding ... ... says. Avg. DC grid-
current is measured with an ordinary panel meter.

### That equates to way below 200 w of grid diss.... based
on 45 ohm input Z... and 800w of drive . I can see we
are well within the grid diss ratings.

For calculation of efficiency you have to deduct the drive power

first

in GG, about 70% of the drive power is seen as output power.
Drive power is not lost totally as with GK.

### I never deduct the drive power... since it really enhances
the eff in the end anyway... another benefit of GG. Bottom line
is... "apparent eff" goes up... anode diss goes down a bit.

If both capacitors of your input network are the same value you

have

no transformation, you will have 50 ohm input from the transceiver
and 50 ohm output to the cathode side.

### yes... u can see that effect on GM3SEK's excellent pi/ pi-l
spreadsheets. Funny how every arrl handbook/qst article
using fixed silver mica's always used same values for C1 +
C2.... which never worked.

I would expect the cathode impedance smaller at that power,

probably

30-40 Ohms.

#### it's about 40-45 ohms. The gain is about 11.54 db at
11.5 kw out.

### Funny thing is... with just 100w of drive... power out is 3
kw [ 3CX-6000A7] It appears on all these big tubes... that
gain is higher with low drive levels... then decreases... with
increasing drive levels.

### The 3000A7 is abt 1500w out with just 50 w of drive.

### Tubes like the higher gain YC-156 have aprx 25 ohm input Z.
Gain is almost quasi proportional between plate load Z and input
Z.

I use that tunable pi-network on my 3CX3K amp, but used a smaller
capacitor on the ouput then on the input. My coil is switched as

well.

I would like to use ganged capacitors there and ganged with a

roller

at the same time, should work with that low circuit Q.

### Henry tried that in the 4 K ultra. Trying to get it to
track was [still is] a real bitch. I wouldn't do it. For
160-10m... u need 4000 pf caps. If u pad smaller 2100 pf caps
like I did for 160m... ur tracking will be out to lunch. You
also seem to get anomoly's from one band to the next.

Any idea of the price of the 4?H roller by multronics?

### No clue It appears identical to their 28 uh unit that
was featured in many qst/ handbook articles over the years...
excpet the little 4.4 uh unit is shorter... and uses 8 ga wire
[.128" solid tinned alloy wire]. I believe the 4.4 uh unit also
has the same tapered pitch at the high freq end.

### Multronics is now a division of Cardwell condenser corp.... I
think it's just cardwell condensercorp.com

Later... Jim VE7RF

73
Peter

Yahoo! Groups Links

R L MEASURES, AG6K. 805-386-3734
r@...

--- In ham_amplifiers@..., "Peter Voelpel" <df3kv@...>
wrote:

Jim,

Grid dissipation is measured by ohms law, grid voltage by grid
current.
Since the grid is at ground, you just measure the cathode voltage

with

a scope.

### whoa. Are you saying RF cathode V x DC grid current
= grid diss ????

### That equates to way below 200 w of grid diss.... based
on 45 ohm input Z... and 800w of drive . I can see we
are well within the grid diss ratings.

For calculation of efficiency you have to deduct the drive power

first

in GG, about 70% of the drive power is seen as output power.
Drive power is not lost totally as with GK.

### I never deduct the drive power... since it really enhances
the eff in the end anyway... another benefit of GG. Bottom line
is... "apparent eff" goes up... anode diss goes down a bit.

If both capacitors of your input network are the same value you

have

no transformation, you will have 50 ohm input from the transceiver
and 50 ohm output to the cathode side.

### yes... u can see that effect on GM3SEK's excellent pi/ pi-l
spreadsheets. Funny how every arrl handbook/qst article
using fixed silver mica's always used same values for C1 +
C2.... which never worked.

I would expect the cathode impedance smaller at that power,

probably

30-40 Ohms.

#### it's about 40-45 ohms. The gain is about 11.54 db at
11.5 kw out.

### Funny thing is... with just 100w of drive... power out is 3
kw [ 3CX-6000A7] It appears on all these big tubes... that
gain is higher with low drive levels... then decreases... with
increasing drive levels.

### The 3000A7 is abt 1500w out with just 50 w of drive.

### Tubes like the higher gain YC-156 have aprx 25 ohm input Z.
Gain is almost quasi proportional between plate load Z and input
Z.

I use that tunable pi-network on my 3CX3K amp, but used a smaller
capacitor on the ouput then on the input. My coil is switched as

well.

I would like to use ganged capacitors there and ganged with a

roller

at the same time, should work with that low circuit Q.

### Henry tried that in the 4 K ultra. Trying to get it to
track was [still is] a real bitch. I wouldn't do it. For
160-10m... u need 4000 pf caps. If u pad smaller 2100 pf caps
like I did for 160m... ur tracking will be out to lunch. You
also seem to get anomoly's from one band to the next.

Any idea of the price of the 4?H roller by multronics?

### No clue It appears identical to their 28 uh unit that
was featured in many qst/ handbook articles over the years...
excpet the little 4.4 uh unit is shorter... and uses 8 ga wire
[.128" solid tinned alloy wire]. I believe the 4.4 uh unit also
has the same tapered pitch at the high freq end.

### Multronics is now a division of Cardwell condenser corp.... I
think it's just cardwell condensercorp.com

Later... Jim VE7RF

73
Peter

--- In ham_amplifiers@..., Jan Erik Holm <sm2ekm@...>
wrote:

Jim,

Grid drive I suppose? In GG I would guess with 200W drive
maybe 5-6 kW, or?

### 9-12 kw out with 200w of drive. ..easy. [7900 v no load]

I?m planing to replace my 2x4-1000A?s with a YC-156, I think
it?s a ideal tube. As soon as I can get hold of a good one
at a decent price, would be a quick swap. However it will
be GG.

The 4-1000A is a pain in the rear end and I?m getting to old
to struggle with them.

#### The trbl with 4-1000's is trying to find good one's
these days. I had single 4-1000's and pairs of em... between
1976- late 80's.

### The YC-156 in GG has a huge amount of gain. 100 w and low
plate v... like 4 kv will do 4 kw out. My buddy had a 4-
1000 amp... he converted to a pair of 8877's.... then later on...
replaced the 2 x 8877's with a single YC-156.... best thing he
ever did.

### They all used a removeable aluminum plate for the tube...
so the plate could be removed... and replaced with another
plate / diff tube/socket combo. Of course all the LC
ratio's on the pi-net had to be changed.

### I'm told the YC-156 has an input Z of 25 ohms.... so base
any tuned inputs around that... and use paralled RG-58 u coax to
make the 25 ohm cable from output of tuned input... to socket.

### also beware.... the YC-156 has 36 pf of anode to grid
C........ which will INCREASE to 50 pf.... when the YC-156 is
bolted to the chassis !!!

### The 3000A7 does the same thing.... anode to grid C is 24
pf.... and rises to 33 pf when plugged into the grid ring.

### The 6000A7 is 24.5 pf anode to grid.... and rises to 36 pf
when plugged in.

### To get these big tubes to work on 20-10m.... you gotta
add .6 uh between plate block cap and tube.... OR just tap
into the 1st .6 uh of main tank coil.... with the vac tune
cap.... amounts to the same thing.

### This will DROP ther plate load Z WAY down.... so the PI
net is designed around this lower value.

### I use GM3SEK's excellent pi pi-L spreadsheet. It factor's
in this L between tube anode and the pi net. Any stray L
between the anode and the input of the PI net will make a HUGE
difference in transformed plate load Z on the higher bands. [I
also use his spread sheet for the pi tuned input calcs]

### also if u have any kind of Z bump bewteen vac load cap and
the vac T/R relay...... you will have a mini PI-L on the high
bands.. esp 10m..... which will put the vac load cap at a sky
high Voltage. 11m ops have used just wire, strap between vac
load cap.. and the vac T/R relay.... and smoked 5 kv rated vac
load caps !!


### I deep sixed 10/12 m from the last bunch of linears I have
built. Also, if you do, beware of trying to re-use the 10m
tank coil tap... on 12M. The Q will sky rocket... and the
circulating currents will cook everything.

Later.... Jim VE7RF

73 Jim SM2EKM
-----------------

pentalab wrote:

### These YC-156's [and YC-172's] are a huge bang for

the

buck. 200 w drive = 10kw + out. No socket required.

$400.00

### after messing about with multiple tube linears in

the

Later.... Jim VE7RF

That was my reason for moving to 4CX3000A and bought 6 for $100.

Jan Erik Holm wrote: