----- Original Message -----

From: R L Measures

To: ham_amplifiers@...

Sent: Saturday, September 23, 2006 1:37 PM

Subject: Re: [ham_amplifiers] Re: HIGH SWR / HIGH REFLECTED POWER SHUT DOWN CIRCUIT !!

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

> --- In ham_amplifiers@yahoogroups.com, 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@...