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K3 PA3000.. you can dream, can't you?

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Jeff Wandling W7BRS-2

K3 PA3000.. you can dream, can't you?

Fun stuff -

I'm not quite looking for the KPA1000, but this is where I'd ultimately
like to go design and homebrew-wise if I could try, someday.. maybe.

(I saw QEX had an article Oct/2006 for a tokyo-style amp - these hams
based theirs on that design)

http://www.mods-ham.com/03_Home-brew/Homebrew-Mods/ARF1500-PA/ARF1500PA.pdf

and a follow up:

http://www.mods-ham.com/03_Home-brew/Homebrew-Mods/ARF1500-PA/ARF_PA_DL6JI.pdf

hosted at:

http://www.mods-ham.com/03_Home-brew/Homebrew_Frame.html

Auf Deutsch. Select all the text, paste it into various translators
online and get a jist of what's going on.

-jeff
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Greg - AB7R

Re: K3 PA3000.. you can dream, can't you?

If interested there's a guy named Yuri near Seattle who has a board with 12 MRF-
150s on it that he tested I think with 25W drive for 1.1KW output. I don't recall
what the power supply was. Think he wanted something like $350 for it. Add may
still be on QRZ.com.

-------------------------
73,
Greg - AB7R
Whidbey Island WA
NA-065

On Wed Feb 11 13:09 , Jeff Wandling W7BRS sent:

>
>Fun stuff -
>
>I'm not quite looking for the KPA1000, but this is where I'd ultimately
>like to go design and homebrew-wise if I could try, someday.. maybe.
>
>(I saw QEX had an article Oct/2006 for a tokyo-style amp - these hams
>based theirs on that design)
>
>http://www.mods-ham.com/03_Home-brew/Homebrew-Mods/ARF1500-PA/ARF1500PA.pdf
>
>and a follow up:
>
>http://www.mods-ham.com/03_Home-brew/Homebrew-Mods/ARF1500-PA/ARF_PA_DL6JI.pdf
>
>hosted at:
>
>http://www.mods-ham.com/03_Home-brew/Homebrew_Frame.html
>
>Auf Deutsch. Select all the text, paste it into various translators
>online and get a jist of what's going on.
>
>-jeff
>______________________________________________________________
>Elecraft mailing list
>Home: http://mailman.qth.net/mailman/listinfo/elecraft
>Help: http://mailman.qth.net/mmfaq.htm
>Post: [hidden email]','','','')">[hidden email]
>
>This list hosted by: http://www.qsl.net
>Please help support this email list: http://www.qsl.net/donate.html

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Rick Dettinger-3

Re: K3 PA3000.. you can dream, can't you?

With that kind of drive requirement, you could skip the 100 watt amp
on the K2 or K3 and go directly to about 700 watts out using the QRP
versions for about the same cost.

73
Rick K7MW
LaConner, WA

On Feb 11, 2009, at 1:38 PM, Greg - AB7R wrote:

> If interested there's a guy named Yuri near Seattle who has a board
> with 12 MRF-
> 150s on it that he tested I think with 25W drive for 1.1KW output.
> I don't recall
> what the power supply was. Think he wanted something like $350 for
> it. Add may
> still be on QRZ.com.
>
>
> -------------------------
> 73,
> Greg - AB7R
> Whidbey Island WA
> NA-065
>
>
> On Wed Feb 11 13:09 , Jeff Wandling W7BRS sent:
>
>>
>> Fun stuff -
>>
>> I'm not quite looking for the KPA1000, but this is where I'd
>> ultimately
>> like to go design and homebrew-wise if I could try, someday.. maybe.
>>
>> (I saw QEX had an article Oct/2006 for a tokyo-style amp - these hams
>> based theirs on that design)
>>
>> http://www.mods-ham.com/03_Home-brew/Homebrew-Mods/ARF1500-PA/ARF1500PA.pdf
>>
>> and a follow up:
>>
>> http://www.mods-ham.com/03_Home-brew/Homebrew-Mods/ARF1500-PA/ARF_PA_DL6JI.pdf
>>
>> hosted at:
>>
>> http://www.mods-ham.com/03_Home-brew/Homebrew_Frame.html
>>
>> Auf Deutsch. Select all the text, paste it into various translators
>> online and get a jist of what's going on.
>>
>> -jeff
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: [hidden email]','','','')">[hidden email]
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html

Jeff Wandling W7BRS-2

Re: K3 PA3000.. you can dream, can't you?

I think this thread may have already boosted itself out of the Elecraft
orbit, so excuse this additional post and I'll take it off line. I don't
know why I even started it here on this list, but the caffeen was probably
clouding my judgement.

I'm not sure about the same cost. Maybe there were some things I
overlooked in the schematic and the posting earlier but the main thing is
solid-state PA's are current devices.. Lots of current.

That one they were based on required 100Vdc @30A. That's tough business
to bring up cheaply, AFAIK.

It's one of the reasons why I was talked-out of starting with solid-state
PA's for homebrew at that power level until I get my feet wet with some
15-50W designs (many ARRL books referenced here). I'm going to try some
tube amps first, get a feel of building the input tuning network and so
forth, undersanding Q, and those subsystems that are required.

After checking with MicroSemi who makes the ARF line, those particular BeO
MOSFETS are quite expensive, new. And the BeO makes them tricky to work
with safely. For a reference design, check out ARRL.org, search QEX,
Tokyo, MOSFET keywords and you'll find the QEX article from 2006 from the
THP designers.

For those so inclined and experienced to do so, it would be an incredible
project -- especially the STAMP programming and so forth to make the unit
really stand out.

The Hayward book on SS design and it's sequel are really interesting
reading too. I have a spare pair of 2SC2782's in bag just waiting for my
own outboard PA homebrew project one of these days.

-jeff

On Wed, 11 Feb 2009, Rick Dettinger wrote:

> With that kind of drive requirement, you could skip the 100 watt amp on the
> K2 or K3 and go directly to about 700 watts out using the QRP versions for
> about the same cost.
>
> 73
> Rick K7MW
> LaConner, WA
>
>
> On Feb 11, 2009, at 1:38 PM, Greg - AB7R wrote:
>
>> If interested there's a guy named Yuri near Seattle who has a board with 12
>> MRF-
>> 150s on it that he tested I think with 25W drive for 1.1KW output. I don't
>> recall
>> what the power supply was. Think he wanted something like $350 for it.
>> Add may
>> still be on QRZ.com.
>>
>>
>> -------------------------
>> 73,
>> Greg - AB7R
>> Whidbey Island WA
>> NA-065
>>
>>
>> On Wed Feb 11 13:09 , Jeff Wandling W7BRS sent:
>>
>>>
>>> Fun stuff -
>>>
>>> I'm not quite looking for the KPA1000, but this is where I'd ultimately
>>> like to go design and homebrew-wise if I could try, someday.. maybe.
>>>
>>> (I saw QEX had an article Oct/2006 for a tokyo-style amp - these hams
>>> based theirs on that design)
>>>
>>> http://www.mods-ham.com/03_Home-brew/Homebrew-Mods/ARF1500-PA/ARF1500PA.pdf
>>>
>>> and a follow up:
>>>
>>> http://www.mods-ham.com/03_Home-brew/Homebrew-Mods/ARF1500-PA/ARF_PA_DL6JI.pdf
>>>
>>> hosted at:
>>>
>>> http://www.mods-ham.com/03_Home-brew/Homebrew_Frame.html
>>>
>>> Auf Deutsch. Select all the text, paste it into various translators
>>> online and get a jist of what's going on.
>>>
>>> -jeff
>>> ______________________________________________________________
>>> Elecraft mailing list
>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>>> Help: http://mailman.qth.net/mmfaq.htm
>>> Post: [hidden email]','','','')">[hidden email]
>>>
>>> This list hosted by: http://www.qsl.net
>>> Please help support this email list: http://www.qsl.net/donate.html
>>
>>
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html