View Single Post
  #2   Report Post  
Old May 30th 07, 11:05 PM posted to rec.radio.amateur.homebrew,sci.electronics.basics,alt.music.makers.electronic,rec.music.makers.guitar,sci.electronics.misc
Mad Scientist Jr Mad Scientist Jr is offline
external usenet poster
 
First recorded activity by RadioBanter: May 2007
Posts: 19
Default radio shielding?

Did you use shielded wire to connect the controls and jacks?

Thanks for your reply...

No, just normal stranded wire. Is that where the most interference
would be leaking in?

I found shielding paint (see below) - would it help to paint the
inside of the project box with this?

http://www.lessemf.com/paint.html

SUPER SHIELD

Reduce or Eliminate EMI / RFI Interference

Super Shield A general purpose EMI/RFI shielding in a handy aerosol
spray for use on most substrates. Especially good for RF shielding
plastic electronics enclosures. Consists of a tough, durable acrylic
base pigmented with a high purity nickel flake. One to two mil coating
provides 40dB - 50dB shielding across a frequency range of 5 to
1800MHz. About 1600 inē/can coverage at 1.5 mil. Contains no CFC 'S,
NO HCFC'S, ozone friendly. 340g (12 oz) aerosol can. Dries to a dull
gray color. Click to see MSDS

* Surface Resistivity ~0.7 Ohm/sq
* Dry time: 10 minutes at room temperature
* Recoat time: 5 minutes
* Excellent adhesion to most plastics
* Tested as per IEEE Std. 299-1997
* Underwriters Laboratories Recognized File No.: E202609
* NO CFC 'S, NO HCFC'S, Ozone Friendly
* RoHS Compliant

Flammable aerosol, ships by ground only.

Super Shield (Cat. #A285) ....................................... $24.95
add to cart







On May 30, 1:26 pm, Meat Plow wrote:
On Wed, 30 May 2007 10:18:26 -0700, Mad Scientist Jr wrote:
I am building an amplifier


(for schematic see page 5 he
http://makezine.com/09/crackerboxamp/
)


but when I turn up the gain, I get buzz and can actually hear some
radio broadcasts on it.


I assume I need to shield the circuit, or parts of it...


Would lining the inside of the project case (in this case a cardboard
cracker box) with aluminum foil work?


Incidentally, does anyone know if someone makes a type of "shielding"
spray paint or primer, that you could just spray on a plastic or
cardboard project box, that would provide shielding?


Any help appreciated...


Did you use shielded wire to connect the controls and jacks?
--
#1 Offishul Ruiner of Usenet, March 2007
#1 Usenet Asshole, March 2007
#1 Bartlo Pset, March 13-24 2007
#10 Most hated Usenetizen of all time
#8 AUK Hate Machine Cog
Pierre Salinger Memorial Hook, Line & Sinker, June 2004
COOSN-266-06-25794