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Re: [RFI] Successful RFI hunt

To: rfi@contesting.com
Subject: Re: [RFI] Successful RFI hunt
From: David Cole <dave@nk7z.net>
Reply-to: dave@nk7z.net
Date: Tue, 10 Feb 2015 04:21:48 -0800
List-post: <rfi@contesting.com">mailto:rfi@contesting.com>
As soon as I have the PS in hand, I will note the make/model here.
-- 
Thanks and 73's,
For equipment, and software setups and reviews see:
www.nk7z.net
for MixW support see;
http://groups.yahoo.com/neo/groups/mixw/info
for Dopplergram information see:
http://groups.yahoo.com/neo/groups/dopplergram/info
for MM-SSTV see:
http://groups.yahoo.com/neo/groups/MM-SSTV/info


On Mon, 2015-02-09 at 14:53 -0500, Michael Zolno wrote:
> Hi David,
> 
> Can you speak to the make, model of the supply? Great ending, sounds like the 
> kids will be able to have some fun!
> 
> All my very best,
> 
> 73, Mike WH6YH 
> 
> Sent from my iPad
> 
> > On Feb 8, 2015, at 12:00 PM, rfi-request@contesting.com wrote:
> > 
> > Hi,
> > Just thought I'd pass on a quick story about a successful RFI hunt
> > today...
> > 
> > A fellow ham who is also a teacher, asked me to assist in locating very
> > bad RFI problem in the new ham station for a local Middle School.
> > 
> > The teacher had installed the station about two weeks ago, only to find
> > a 20 over S9 noise level on all bands, he has spent the past 2 weeks
> > looking for it.  The antenna is perhaps 50 feet away from the station,
> > on the roof and is an R6 vertical.
> > 
> > Being a school I expected the hunt to take a few hours or more, the
> > school sits on an acre or so.
> > 
> > So I brought in my trusty FT-817, and the small hand held loop.  Almost
> > instantly upon powering the FT-817, the RFI was present, and loud!  I
> > DFed it using the small loop, and drew an imaginary line on the null in
> > my head, then walked into the hallway, maybe 50 feet away from the first
> > point, and did the same thing...  There was a huge difference in
> > bearing.  I did a mental triangulate on it, and was the Ham Station!  
> > 
> > I went to the station, and unplugged everything but the radio, and the
> > RFI ended...  Did the unplug each device one at a time process, and
> > found it to be the switching supply for the laptop intended for Digital
> > work.  
> > 
> > The power supply was 50 feet from the antenna, and generating 20 over
> > S9.  I finally killed the radio, and you can hear it with your ear!  It
> > was buzzing, in the audio spectrum as well as spraying RFI
> > everywhere...  
> > 
> > The teacher had an O-Scope there, so I put it on the power line to look
> > at what was happening...  What a mess!  signals all the way up to around
> > 50 MHz.  
> > 
> > Suffice to say, the RFI is gone now, and the Middle School students will
> > get their first exposure to Ham Radio Monday, when the ham/teacher,
> > shows them JT65-X in action!  
> > 
> > I have the Power Supply, and will use it for presentations... 
> > 
> > Some RFI stories turn out good, just thought I'd share a good story!
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