Carl wrote:
>----- Original Message -----
>From: "Ken" <kenw2dtc@comcast.net>
>To: "Ian White GM3SEK" <gm3sek@ifwtech.co.uk>; <amps@contesting.com>
>Sent: Tuesday, April 21, 2009 12:45 PM
>Subject: Re: [Amps] RE K2RIW 2 Meter Amp.
>
>
>> "for the record, did you guys really mean a 2m - repeat, 2m - version
>> that
>> was designed, built and published by K2RIW himself?"
>>
>> No, I don't think K2RIW ever designed and built one. The following
>> PDF file
>> shows that W2GN actually designed the 2 meter version based on the
>> K2RIW 432
>> design. Beware that the PDF file is over 7MB in size and after the
>> download, it takes another 2 minutes for format the file for your
>> screen.
>> The PDF is highly detailed for those who want to build the
>> "K2RIW/W2GN" 144
>> mhz amp.
>>
>> http://www.newsvhf.com/2m_stripline.pdf
>>
>> 73,
>> Ken W2DTC
>Then Im mistaken on the source as I built a 2 x 4CX250B 2M amp in the
>mid to late 60's. It was long before Freds ARCOS version.
>
>Carl
>KM1H
There were many push-pull 4CX250B designs around for 2m at that time,
but K2RIW seemed to be the first to tame the parallel connection using a
wide stripline. That was a half-wave line for 432MHz in the familiar
12in box.
K2RIW's articles were published in 1972. Not long afterwards, QST had a
photograph of a 2m version that someone had made, with a half-wave line
in a loooong box; but as far as I know it was W2GN who re-engineered it
as a quarter-wave for 2m (also borrowing from an 8877 design by Meade).
Fred then designed the complete ARCOS line of VHF/UHF amps using the
same basic metalwork for all bands, 50 through 432MHz. This included
some minor re-engineering of the K2RIW to make the grid and anode
circuits tune more easily.
The designs for 50, 144 and 220MHz were published in 'Ham Radio' around
1977 but the 432MHz design wasn't. The 432MHz details eventually
appeared in 'The VHF/UHF DX Book' with permission from Fred's widow.
(For complete disclosure, I was also involved in the final batch of 2m
amplifier kits from the UK that were sold through Down East Microwave in
the mid 90s. I still have the prototype with a pair of Svetlana
4CX400As.)
--
73 from Ian GM3SEK
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