Newsgroup: it.hobby.radioamatori
Titolo: Messagio strano....

Questo messagio e comparso su il blog e podcast SolderSmoke
http://soldersmoke.blogspot.com
  Data 1 Aprile.  Mi sembra molto
strano...
TO: 
solde...@yahoo.com
FROM:i.no...@primaprile.it
SUBJECT: CHEMICAL TAILORING OF CRYSTAL MICROPHONE AUDIO RESPONSE
Ciao Bill! Greetings from not-so-sunny Roma! After I read you blog
posting --
http://soldersmoke.blogspot.com/2011/03/homebrew-literally-
your-own-microphone.html â€“
with the video about how to grow your own piezo-electric crystals at
home, I was reminded of an article from an old Italian radio magazine
that I came across not long ago. Having heard of your recent (well,
long-standing) problems with audio quality and microphones, it
occurred to me that this old Italian article might be the solution to
your audio difficulties.
The article appeared in the Italian radio magazine "Radio-Furbizia"
April 1950. Tough times in Italy! Hams had to be inventive and
ingenious, and they had to put to work whatever resources they had at
hand. Dottore Andrea Bugiardo, I0SOL, was clearly a man for those
times. During the post-war period, writing from his hamshack in the
beautiful village of Scherzo-Barzelleta, in the province of
Truccoimbroglio, OM Bugiardo produced a steady stream of truly
incredible ham radio innovations.As you know, life in an Italian home
revolves around the kitchen, so it should come as no surprise that
Bugiardo based many of his devices on things that he found there.
Bugiardo opens his April 1950 article with a really touching admission
of his deep, unfulfilled yearning for a Astatic D-104 microphone. I
know this mic was not warmly received by your listeners (insensitive
brutes!) but for Bugiardo, the D-104, with its chrome and its art-deco
lines was the epitome of ham radio class! As you know, style and good
design are important for Italians -- this is the country of "bella
figura!" But alas, the dire economic situation did not permit Dr.
Bugiardo to buy his coveted chrome lollipop. But, being a true ham, a
ham's ham, he decided to "roll his own"as you Americans would say. He
decided to build his own D-104.
The exterior did not represent a major problem. He had many friends in
Milano who could handle the needed metal and chrome work. The problem
was electrical... or should I say electro-mechanical. You see,
Bugiardo needed the key component, or perhaps I should say, the key
ingredient: he needed the piezoelectric element, the transducer, the
piezo-electric device that transforms sound to electricity.  It is
very interesting. In growing his crystals, Bugiardo employed
essentially the same techniques as described in the video on your
blog. But -- and here is where I think his article could help you --
he went a significant step further and described how -- by using
simple substances found in any kitchen -- the audio characteristics of
the microphone can be tailored to the needs of any individual human
voice. Bugiardo's research showed that by adding certain common
crystalline substances to the standard mix for piezo-electric crystals
(the familiar Tartar sauce formula) we can actually come up with the
kind of mic we need! No need for EQ or mixer boards! Just start out
with the right kind of crystal for your voice, and you are, as you
guys say, â€œ good to go!
The physics of this is all based on the physical mechanics of the
crystals -- motional inductance and all that. I'll spare you the gory
details. Here is the essential information:
-- You start with the standard mix for the crystal element as
described in the ARRL Handbooks (this formula appears in all the
handbooks from the 40's and 50's).
-- In order to have a mic that accentuates the high notes in the
voice, add approximately 5 grams of sugar to the mix.
-- For a stronger bass response, highlighting the low frequencies, add
approximately 5 grams of salt. Ordinary table salt will do.
-- For a "punchy" DX-hunter's sound, Bugiardo recommends adding some
Tabasco sauce to the Tartar sauce before the initial mixing. (He says
this will give you about 3.2456 db gain!)
-- As for your whistling SSSSS problem, Bugiardo's "cook book" does
seem to hint at a solution: He says that by adding some molasses to
the mixture, you can sort of "smooth out" the response. (This is no
doubt caused by the molasses adding its sticky-ness to the crystal
matrix.) PLEASE give this a try Bill.  Mama Mia! Those whistles hurt
my ears!
Anyway, I hope this proves useful. We all really enjoy the podcast.
Ciao,
Carlo

:-)
ha scritto nel messaggio 
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