Actually the value of 20 pF/meter (-j27) is also quoted at several places in my
1970 edition along with 13 pF/meter.
Presumably these values result in "reasonable" cathode circuit Q's (2 - 3) with
the input impedances
(in the region of 100 ohms) of then commonly used grounded grid tubes (see i.a.
the table on page 191).
73/
Karl-Arne
SM0AOM
----- Original Message -----
From: "Peter Chadwick" <g3rzp@g3rzp.wanadoo.co.uk>
To: "Bill Fuqua" <wlfuqu00@uky.edu>; "Roger D Johnson" <n1rj@adelphia.net>;
<garyschafer@comcast.net>
Cc: <amps@contesting.com>
Sent: Saturday, March 25, 2006 10:11 AM
Subject: Re: [Amps] Tuned input board on SB-220
> What is the rationale for the magic 13pF/metre? It works out as -j41....and
> please don't say 'because it's in Bill Orr's book!'
> 73
> Peter G3RZP
> _______________________________________________
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