Time for an update, I think!
I think most of you have received photos of what I'm contending with
and for several reasons I felt it was definitly the power company's
creation. considerable evidence was present to indicate that the
noise was both on the power line and also being radiated.
Fortunately, since there isn't too much SDR equipment in this corner of
Wisconsin, periodically I get requests from people who want to see the
stuff in person. Last week a couple of guys came. One of them was a
retired maintenance supervisor from my power company! He took one
look at the panafall, asked that I give him some examples of what this
stuff sounded like and without hesitation announced that it was coming
from MOV or insulator breakdown, probably both and not too far from me.
Now comes the problem. This is one of the smallest farmer's co-op
power companies in the state and do not have very much in the way of
technical expertise. They will have to borrow "someone" and some
equipment. So I will probably have to wait some time for things to
happen. Actually, since we are in the middle of a drought, the noise
isn't too bad at the moment. I know I have to wait for a
"resurrgence."
73
Lee
Quoting Rob Sherwood <r...@nc0b.com>:
I have been fighting RFI from my computer system at my rural QTH for
two years. (4 logging PCs in the ham shack, 1 family PC, 1 file
server and a Motorola
Canopy wireless Internet link with a 10 mile hop to my access point.)
The spurs
were quite annoying on 20 meters and up, all of which went away when I killed
the router and Ethernet switch. There were four 100-foot runs to the
shack, a
75 foot run to the utility room for the file server, with the router
and switch
in the family room. Now I am using fibre optic cable to the shack, the Fibre
switch is at the server, and one fibre run goes to the family room.
The short
RJ-45 cables in the family room are shielded CAT6, with the shield
connected on
one end only. The RFI is way down, but not 100% gone. I will now experiment
with ferrite toroids on the RJ-45 to the Motorola receiver that is mounted 45
feet up tower #1. I don't know if it is worth getting rid of the two 10 foot
runs of RJ-45 in the family room between the switch, PC and Ethernet HP laser
printer.
Some attention may be required of the switching power supply wall
warts, but I
think their radiation between 14 and 51 MHZ is minimal.
Moving everything to Fibre was not trivial, but all the NICs and the Fibre
switch were purchased on the used market. I believe some of the multi-multi
contest stations use shielded CAT 5e or CAT6 to connect all the
computers. In
my case another reason for the switch to Fibre was EMP from lightning
strikes. Last summer a near-by strike a few 100 yards north of our
home took out one
computer embedded NIC and the Dish Network DVR. With hundreds of
feet of RJ-45
running all over the place, it seemed wise to kill two birds with one stone.
73, Rob, NC0B
>>> Tim Ellison <telli...@itsco.com> 8/3/2009 8:24 PM >>>
See my comments below.
-Tim
-----Original Message-----
From: flexradio-boun...@flex-radio.biz
[mailto:flexradio-boun...@flex-radio.biz]
On Behalf Of Kevin Hobbs
Sent: Monday, August 03, 2009 8:52 PM
To: 'Flex Radio'
Subject: [Flexradio] Birdie Hunting
I went Birdie hunting tonight . found a few couldn't kill them.
1) I was getting tired of a Birdie on 50.125 and having to run ANF all
the time . unplugged my wireless router (my Flex computer is cabled)
and it went
away . suggestions?
[Tim] A "birdie" is not a real descriptive term for what you are seeing. That
term usually describes RF signals internal to the radio like DDS spurs. What
you are seeing is an actual RF signal; RFI from the wireless router.
The fix? Turn off the wireless router :-) Sometimes a plethora of ferrite
beads on all wires egressing the wireless router will fix it, but
sometime not. It could be the switching power supply "wall wart"
causing the noise. You can
also try moving it to another location. The cheaper wireless routers are
notorious for excessive spurious emissions.
2) I guess there is no way to get rid of the 9 Khz Birdie? Ie: Main RX
50.100, Sub RX gets a Birdie on 50.091 (oe 9 KHz below main RX Freq).
Engaging SR does move the Birdie a bit.
[Tim] This too is not a birdie, per se. This is the 0 Hz IF or "DC noise" of
the A/D converter. You can't get rid of it. Refer to the following
KB article.
http://kc.flex-radio.com/KnowledgebaseArticle50176.aspx
73 de Kevin
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