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!
_______________________________________________
RFI mailing list
RFI@contesting.com
http://lists.contesting.com/mailman/listinfo/rfi
|