[RFI] 160 Meter Interference

Jim Brown jim at audiosystemsgroup.com
Wed Oct 6 12:05:38 EDT 2004


On Wed, 6 Oct 2004 11:18:19 -0400, Tom Rauch wrote:

>The 90kHz spacing and reasonably clean carrier is a dead
>giveaway. 90 kHz is in the most common range of low or
>medium power switching power supplies. 

Now that you mention it, you remind me of related set of noise sources 
that I've found to be particularly nasty. They are the battery chargers for 
powered drills and screwdrivers. The noise they produce is largely hash 
(at least on 50 MHz where I have specifically identified it).  I identified the 
source when my friendly carpenter was here doing some work.  I haven't 
had the opportunity to identify their sound  at HF -- maybe the same, 
maybe not. My nextdoor neighbor is a carpenter, and I suspect some of 
the hash I hear may be his chargers.  It's something I need to check out. 
Luckily we're friends, and his dad is a ham. 


Jim Brown  K9YC




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