Hi
Don,
Speaking
of slide rules¡
I
used one in my first year at the technical school, but the
next year, the HP-35 and the TI hand calculators came in
(halleluiah !).
Just
making a series-parallel conversion with the slide rule was
a pain in the ¡ you know what.
And
yep, world is full of mysteries, but I believe we can solve
this one.
?
73,
Jacques, VE2JFE in Montreal
?
?
Hi
Jacques?? I also had a similar concern/thought, but since
the alignment had indicated too much capacitance, both were
in general agreement, so not so much need to ask.
I
think the original sweeps were mostly intended just to get
some sort of look at the response.
I
would not want to expect accuracy unless the probe does not
disturb the circuit . ??It would be good to understand how
much error can creep in. and¡I hope your slide-rule is well
lubricated too. Mystery continues.
?
From: [email protected]
[mailto:[email protected]]
On Behalf Of Jacques_VE2JFE via groups.io
Sent: Saturday, February 22, 2025 2:33 PM
To: [email protected]
Subject: Re: [HallicraftersRadios] S-85
refurbish: I've got a problem during the RF alignment of
bands 1 and 2 - trimcaps don't peak!
Importance: High
?
Hello
Emanuele,
One
time again, I performed some calculations from your test
results below.
IF
there is no error in the C7A capacitor and L3 sections
measurements,
your test results constantly shows an effect of EXCESS
capacitance in the tested antenna circuits.
Could
that be induced by the test setup you use ??
The
attached .pdf contains the calculated ¡°excess capacitance¡±
values (that are not constant, btw).
And
also the kind of test setup I will use to perform such
tests.
?
Maybe
I missed something from the (very) long thread of exchanges
about this problem, but the test setup you used is still not
clear to me.
I
just want to mention that measuring the resonant frequency
of a parallel circuit requires high impedance from both the
RF source used and the instrument displaying the result.
?
As
one of my colleagues already mentioned: ¡°Nothing is more
useful than a good theory¡±.
And
I still believe that it is true.
?
Let
us know !
?
73,
Jacques, VE2JFE in Montreal
--
don??? va3drl
