--- 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
