Call Search
     

New to Ham Radio?
My Profile

Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question

Operating
Contesting
DX Cluster Spots
Propagation

Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net

donate to eham
   Home   Help Search  
Pages: Prev 1 [2]   Go Down
  Print  
Author Topic: HAs anyone ever had to shield their hard drive?  (Read 3584 times)
KF7CG
Member

Posts: 1213




Ignore
« Reply #15 on: March 15, 2007, 09:57:46 AM »

I have noticed too, all the newer power supplies have neglected the heavy RFI filters that at one time were built into the input power cord socket. These were brute force RC filters that stood a very good change of eliminating the hash put out by the switching type supply.

Now that most home electronics are digital and AM radio is not used as much, these filters are disappearing from computer power supplies.

KF7CG
Logged
KG6OMK
Member

Posts: 107




Ignore
« Reply #16 on: March 15, 2007, 12:41:56 PM »

"Screen door screen made no change "

If you are going to plug a hole in the case with screen, the screen needs to be electrically bounded all around the perimeter of the hole it is to plug.  Using tape or glue is ineffective.  About the only way is to make sure there is bare metal to metal contact and then use a clamp of some kind.  Note that aluminum will oxidize and the clear oxide coating that naturally develops is an insolator.  Bonding is typically  done with spot welding every 1/4 inch or so or  with clamps secured with screws.  It is very hard to get a good contact between a screen and sheet metal  without a mechanical clamp or welding/brazing. and the contact has to be all around the perimeter of the screen patch.
You might try using closly spaced screws or pop rivits and large washers to clamp the screen to the sheet metal

The best solution will be to buy a new high quality case and make sure all the screws are tight and in place.  Then connect the case to your station common ground point with a  solid copper strap or very large diameter wire. I have a 1" diameter copper pipe running just under the radio/computer desk that serves as a station ground.  A quality case will have no large holes in the metal not even for fans.  The fans need to blow through a metal grid of some kind.  After this place ferite cores on all of the cables.  Plug the computer into one of those "iso bar" power strips.  to top of the line isobar strips have RF chokes on each outlet

Logged
KC8ADU
Member

Posts: 0




Ignore
« Reply #17 on: March 24, 2007, 02:19:57 AM »

those pretty windowed cases loaded with led fans and ccfl lights usually come with junk power supplies.
we call them gutless wonders.
no rfi/emi filtering at all.jumper wites for chokes and empty spots for caps.
post the brand/model of yours or better yet open it up and post a pic.
Logged
Pages: Prev 1 [2]   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!