Topband: Need More Help Getting rid of Router Birdies

Howard W3CQH hsgorden at
Thu Feb 21 12:19:37 EST 2008

 Message: 1
> Date: Wed, 20 Feb 2008 23:35:04 -0600
> From: Ed Gray W0SD <w0sd at>
> Subject: Topband: Need More Help Getting rid of Router Birdies
> To: Topband at
> Message-ID: <47BD0D88.1040103 at>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> 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 W0SD

1>    You might want to try and shield all cables with tin foil.
2>    You might want to try and shield the computer with tin foil as well as 
        router box, but not the router antennas.
Howie W3CQH 

More information about the Topband mailing list