----- Original Message -----
From: "Andy talbot" <[email protected]>
To: "Rsgb_Lf_Group (E-mail)" <[email protected]>
Sent: Wednesday, April 23, 2003 2:32 PM
Subject: LF: Amidon Cores (slightly diverging from topic)
Does anyone know of a UK supplier of Amidon iron dust cores - they may be
called American Cores & Electronics now, according to the Amidon web page.
The
web is not too helpful at finding a UK stockist though.
I need a lot of them for a (work based) design with many parallel channels
of
filtering, and for various bureaucratic reasons to do with importation,
need
to get them from a UK supplier.
btw. I've discovered the published Al values for these, particularly for
the
T2 material (2 - 30MHz) is some way out from that shown in the ARRL
handbook.
Measured discrepancies of 10% to 30% seem to be common, so every coil
has to
be wound and measured to get to spec
This is normal procedure, published figures are usually a rough guide
because of variations in core material etc.
Like all the other measurements about radiated power from transmitters they
can vary by up to 20 db as discussed in previous messages posted here over
the years. It is impossible to calculate whether the person is emitting 1w
or 10w
All guess work, you must have seen some of these discussions, after several
pages of formulae the conclusion are that these calculation are within 10 db
or so. ie could be 1w or 10w erp. Never believe anything you hear or
see!!!!!!!!!
Too many pretentious experts not surprisingly from the South, and often
adamant that they are right!!!!!!!!
Fortunately north of Watford, especially Scotland and Ireland we do not fall
for this.
G3KEV
Andy G4JNT
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