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From: John Rabson <john.rabson@numeo.fr>
In-Reply-To: <201107061206.01983.rick@hartmantech.com>
Date: Thu, 7 Jul 2011 11:41:45 +0200
Cc: rsgb_lf_group@blacksheep.org,
 Robin Gape <robingape@ukfsn.org>
Message-Id: <18D08C47-772B-4F77-91E8-CFE11AA814E7@numeo.fr>
References: <516CAAC2-5EF6-456A-80E9-A4697777371E@numeo.fr> <201107061206.01983.rick@hartmantech.com>
To: Rick Jenkins <rick@hartmantech.com>
Subject: LF: Re: Circuit Analysis Programs
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Many thanks everyone.  I'm spoilt for choice.=20

John F5VLF

On 6 Jul 2011, at 20:06CEST, Rick Jenkins wrote:

> Hi John,
>=20
> On Wednesday, July 06, 2011 11:21:35 AM you wrote:
>> I am experimenting with various forms of matching network to go =
between my
>> 136kHz antenna and the transmitter. It would be very handy if I had a
>> fairly simple circuit analysis program with which to do the =
following:
>>=20
>> Having measured the input impedance to the combined matching unit and
>> antenna, then =93subtract=94 the components of the matching network, =
see what
>> I get and compare it with what I actually measure. I'm not always
>> convinced that what I measure is what I think I'm measuring.
>>=20
>> Platforms available: XP, Linux and MacOs X.
>>=20
>> Yes, I could write something, but somebody must have done this and =
there is
>> no point in reinventing the wheel.
>>=20
>> Any suggestions, please?
>=20
> Faced with the need to do math, I usually turn to Maxima. This is a =
descendant=20
> of the original DOD Macsyma, now with an open-source license. I run it =
on=20
> Linux, but I am told the W*ndows version is good too.=20
>=20
> With a little fiddling I can usually carry through a symbolic s-plane =
analysis=20
> of a network with not too much trouble, then substitute s=3Djw, then =
throw in=20
> numerical values and plot the results. There is a visual interface =
called=20
> wxmaxima, and plotting is best done via gnuplot.=20
>=20
> It takes a while to do your first analysis, but as you use the system =
you=20
> slowly come to understand its philosophy, and life gets faster and =
slicker. I=20
> find this *much* more accurate than fiddling about with pencil and =
paper. Maxima=20
> never drops a sign or a 2*pi.
>=20
> Hope this helps,
> --=20
> Rick Jenkins <rick@hartmantech.com>
> Hartman Technica           http://www.hartmantech.com=20
> Phone +1 (403) 230-1987
> 221 35 Avenue. N.E., Calgary, Alberta, Canada T2E 2K5
>=20