Topband: Need More Help Getting rid of Router Birdies

Ed Gray W0SD w0sd at
Thu Feb 21 00:35:04 EST 2008

I got my $100.00 worth of type #43 ferrite that are exacty the ferrite 
that has been recommended for curing router birdes on this reflector.  I 
have wrapped 9 turns of the CAT cable through and around the ferrite 
core and it makes absolutely no difference.

Today three of us hams worked on the birdie problem for quite awhile. 
Here is what we found.  It seems to be something to do with the birdies 
being generated in the computer, ie the circuitry that talks to the 
router.  It happens with all my computers but on my newest one when you 
shut it off some circuitry stays powered up and the light on the network 
card stays on and the birdies only go away when you pull the AC cord off 
the computer.

We took the side cover off the computer and the birdies do not get worse 
so more sheilding does not seem to be the answer.  It is a good steel 
cabinet, well shielded.  We unhooked everything from the computer other 
than the AC cord and the CAT cable and no change.  We wrapped 9 turns of 
the AC power cord through the ferrite core and it made no difference. 
As I said having 9 turns of the CAT cable wrapped through the ferrite 
core makes no difference.  We tried less turns and no change.

On beam antennas aways from the house you can peak the signal by beaming 
on the house or lose the signal beaming away from the house.  We tried 
different runs of CAT Cable seeing if it would change the signal 
strength thinking the CAT cable was acting as an antenna and it made 
absolute no difference.

I also have an AC line filter on the computer which cured my switching 
power supply noise. We also tired the ferrite core on the power cord to 
the Router which was a desperation idea as our tests seem to indicate it 
is being generated in the computer if the router signal is coming into 
the computer.  We hooked the DSL modem right to the computer and the 
birdies are gone.  It would seem the birdies are being radiated by the 
CAT Cable and the ferrite is not attenuating it at all.  I also tried a 
clip on ferrite and no effect.  I don't have any shielded Network cable 
and all I read is that really should not be necessary.

The birdies happen on all bands 160M through 10M.  I have not checked 
six meters and above as I just moved into a new radio room and don't 
have those bands hooked up yet.

We need some fresh ideas as we have ran out of ideas to try next.  It 
happens with all three of my computers in this same way.

I also have a laptop with a wireless card and it gives no problem(no 
birdies)as long as you don't have a CAT cable hooked to one of my three 
computers and as I said there is not problem if the computer is not on.

The only solution so far that would seem to work is to buy a wireless 
card or the USB wireless adaptor for each desktop computer and forget 
the CAT cable.  I base this on having no problem with using the wireless 
card in the laptop.

Every computer hooked to the router has its own set of birdies so with 
three computers hooked up I have quite a number of birdies, some very 
loud depending on the antenna orientation.  If I just have two on there 
are less and with just one on there are not all that many.  I can rank 
the computers as to which produces the most birdies and the least.

Does anyone have suggestions of things to try before trying the wireless 
connection? The birdie does at times have a bit of worble to it and it 
seems to be when the light is flashing on the Network card.


Ed Gray W0SD wrote:
> I need these to surpress my router noise and have several runs of Cat5e 
> cable so I need several ferrite cores. . The best price I have found is 
> $9.00 for the #43 and $10.00 for the #31.  Does anyone know where I can 
> beat this price.
> Thank you,
> Ed W0SD
> _______________________________________________
> Topband mailing list
> Topband at

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