Hi Johan, yes a quick look suggests a value of anything over about 120uH
would do the job at 136 with a 10ohm load. I looked for data when I started
to experiment as I am sure you did and just built a big choke with thick
wire in a 50mm FX2240 pot core. It measured out at about 2mH and really
"clunked" at switching on.
I must read in more detail as at a first scan I did not see the choke
resistance in any equation. Most test amps made used at least 500mH I think
at 136, though what the effect of the current thought the choke and the
field in the ferrite was I havent a clue. I did not look for saturation.
Nice Find
Thanks Alan G3NYK
----- Original Message -----
From: "Johan H. Bodin" <[email protected]>
To: <[email protected]>
Sent: Friday, March 07, 2008 8:35 PM
Subject: LF: Smaller DC feeding choke in class E amplifier
> LFers,
>
> the usual design equations for class E amplifiers assume that the DC
feeding
> choke has a very large inductance in order to keep the DC current
practically
> constant over the RF cycle. I am in the process of building (yet another)
class
> E CW QRP transmitter and the need for an almost infinite inductance has
annoyed
> me for quite a while. Somewhere between the solder smoke puffs, I did some
> googling and found this interesting paper:
>
> http://www.msm.ele.tue.nl/~dmilosev/ECCTD2005.pdf
>
> My current project is a small 80m TX but I think this information is
applicable
> to LF as well.
>
> 73
> Johan SM6LKM
>
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