[AMPS] L4B

[km1h@juno.com (km1h@juno.com)]

On Thu, 15 Oct 1998 21:58:25 +0100 "Ian White, G3SEK"
<G3SEK@ifwtech.demon.co.uk> writes:
>
SNIP

>
>"What price" comes into this very literally. In Europe the classic 
>8.2V
>50W zeners are very hard to find.

Ian...in the Colonies:
 Anywhere from $7 -15 depending on voltages and who has what when. K2AW
is often a very good source.



 From the big catalogs, the choices 
>are
>between a 20W diode at $10 (but probably under-rated in a flashover) 
>or
>a 75W diode at $50 - and neither of those has adjustable voltage.
>
>The cost-effective alternatives then are either a string of forward-
>biased diodes or something involving a transistor.

Which is as likely to blow during an Oh-Oh ( aka: Oh Shit) as a zener. A
handful of 25 cent 1N5408's are less high-tech but also lots more
reliable to contesters and other hard users of amps. Personally, I
absolutely hate fixing things at 3AM.


>
>One reason for microwavers liking regulated bias voltage is that it
>allows more RF output in the common situation where drive power is 
>hard
>to find and small tubes are being pushed to the limit. But mostly I
>think it's the "follow-my-leader" effect.

Pretty soon the 3CX100A5/7289 will be as extinct as 8873's the way the
23cm group abuse them.

73  Carl  KM1H


>
>73 from Ian G3SEK          Editor, 'The VHF/UHF DX Book'
>                          'In Practice' columnist for RadCom (RSGB)
>                           http://www.ifwtech.demon.co.uk/g3sek
>
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>
>

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