[RFI] Sling Link RFI

Scott Yost nm8rmedic at rocketmail.com
Wed Jul 11 10:36:04 PDT 2012


Looks like it was Mr. Johnson who had the idea of offering a wifi setup.  Good idea.  


(off topic: related to Kelly Johnson of P-38 design fame?)



________________________________
 From: Kelly Johnson <n6kj.kelly at gmail.com>
To: Scott Yost <nm8rmedic at rocketmail.com> 
Sent: Wednesday, July 11, 2012 11:59 AM
Subject: Re: [RFI] Sling Link RFI
 
An AC filter will probably not help.  The RFI is most likely being
radiated from the neighbor's AC wiring and coming directly into your
antenna.  The only solution is to eliminate the source of the noise.

I am surprised that this box is doing this.  This is call Powerline
Ethernet and the manufacturers of those devices all (AFAIK) adhere to
a design standard which notches the HAM bands so that no signals are
put into the ham bands.  Most people say that these devices don't
cause problems, including the ARRL's Ed Hare.

There are lots of devices that do "ethernet over home wiring".  I
won't use one in my own home, but I'm told that they are relatively RF
quiet and should not cause problems.  I suggest you look into buying
your neighbor another branch of powerline ethernet adaptor OR a high
speed WiFi adapter so the neighbor gets the ethernet he wants and you
get no RFI.

You may want to contact Ed Hare at ARR for more information and/or
suggestions.  He will probably want to know about this noisy device so
he can test it and report it to the FCC if it violates FCC rules.


On Wed, Jul 11, 2012 at 8:44 AM, Scott Yost <nm8rmedic at rocketmail.com> wrote:
> Could use some advice on a whole-house AC filter to reduce
> RFI in the SW spectrum.
>
> I’ve tracked down two RFI sources this summer.  One was an arcing junction box connection in
> my neighbor’s home (we fixed it) and the other turned out to be a wireless ethernet
> device he had plugged in but was no longer using, called Sling Link.  It blankets the SW spectrum with a constant
> snapping, arc-like noise.  We unplugged
> it and I brought it home for a post-mortem and to take some photos.  I turned on the SW rig to celebrate, but
> quickly found out I have another neighbor with one of these darn boxes.
>
> Here is the description from the manufacturer:
> “A SlingLink™ is a
> convenient way to connect your Slingbox to the Internet. If you're like most
> people, you don't have an ethernet jack right next to your television. Rather
> than running long wires all around your house, or having an expensive
> technician re-wire your home, you can just purchase a pair of SlingLink
> adapters.
> Like an extension cord
> for the Internet, the SlingLink uses your home's existing electrical wiring to
> transmit the ethernet signal from your router. Plug one SlingLink into the wall
> near your router, and plug in the other SlingLink wherever you have your
> Slingbox installed. Voila - your Slingbox is connected to the Internet!”  - end -
> The AC wiring makes a great radiator, and with 7 neighbors
> sharing the distribution transformer, it has a lot of wiring to use.
>
> Any recommendations on AC line filtering I can place on my
> home’s wiring to at least eliminate it in my own home?
>
> Thanks,
>
> ScottNM8R
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