On Sat,7/25/2015 11:51 AM, Kenneth G. Gordon wrote:
On 25 Jul 2015 at 13:31, Randy Farmer wrote:
Ethernet birdies.
Ah. Makes sense. Dang.
You're lucky to have only two.
Each of those birdies around 14030 are synchronized to the clock on
someone's router or switch. If you have neighbors, you'll hear a birdie
for each of them. Identify your own by killing power to your router or
switch. Ethernet also produces birdies around 21060, on the low end of
10M CW, and the low end of 6M. There are also a few on 30M. These are
the ones I've noted because I'm a CW op -- if you work SSB, you may find
more. :)
Well, actually, I don't KNOW that I have only two. On 40 and 80 there appears a
"wandering" bit ofpretty loud crap that is pretty broad, and wonders up and
down the band at
intervals.
I haven't tracked that one down yet, but suspect it is some sort of switching
power
supply somewhere close by.
Right -- they are harmonics of Switch-Mode Power Supplies. Everything
from wall warts to computers to TVs to battery chargers of all sorts.
Well, we have both wired and wireless in our local net. Up to 5 computers, 3 of
which are
hardwired.
And, at this point, then, there isn't much I can do about them, I would suppose.
I have added multiple turns of cat 5 through large ferrite "chokes", but mostly
to keep my
transmitter out of the hub. That worked.
Long cables will need a choke at both ends, and you may also need a
choke on the power supply cable.
Consider adding WiFi adapters to your wired computers to eliminate
radiation from those cables. I've been using nothing but WiFi in my home
and shack (which is in a detached garage), and have all the bandwidth I
need -- enough to support streaming audio and video.
73, Jim K9YC
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