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K3 birdies - question?

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K2QI

K3 birdies - question?

Dear group,

At first I thought I did not have any noticeable birdies, but now it seems
that I have developed a few. It's probably from moving cables and such
around inside the rig.

When I tune quickly through a band, I can hear solid tones that change in
pitch as I move up or down in frequency. The weird thing is, they don't
behave like I thought a birdie would. In my case, disconnect the antenna
and the tone practically disappears below the noise floor. Reinsert the
antenna, and it comes back. Also, switching from my antenna on ANT1 to the
dummy load on ANT2 or the RX connector removes the birdie as well.

The NB has no effect, but the notch feature does. For example, moving the
notch to 2700Hz wipes out a strong signal tone on 28.380

I haven't tried the birdie mapping feature yet, so I thought I'd ask. is
what I'm hearing considered a birdie in this case, or just DDS signal noise?

73,

James KC2UEE

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--... ...-- -.. . .--- .- -- . ...

Grant Youngman

Re: K3 birdies - question?

What you're hearing aren't "birdies". If they go away when you remove
the antenna, then obviously they're signals being picked up by the
antenna from some source outside the radio. Do you her them on
another receiver connected to the same antenna?

Grant/NQ5T

On Mar 3, 2009, at 11:22 PM, James Sarte wrote:

> Dear group,
>
>
>
> At first I thought I did not have any noticeable birdies, but now it
> seems
> that I have developed a few. It's probably from moving cables and
> such
> around inside the rig.
>
>
>
> When I tune quickly through a band, I can hear solid tones that
> change in
> pitch as I move up or down in frequency. The weird thing is, they
> don't
> behave like I thought a birdie would. In my case, disconnect the
> antenna
> and the tone practically disappears below the noise floor. Reinsert
> the
> antenna, and it comes back. Also, switching from my antenna on ANT1
> to the
> dummy load on ANT2 or the RX connector removes the birdie as well.
>
>
>
> The NB has no effect, but the notch feature does. For example,
> moving the
> notch to 2700Hz wipes out a strong signal tone on 28.380
>
>
>
> I haven't tried the birdie mapping feature yet, so I thought I'd
> ask. is
> what I'm hearing considered a birdie in this case, or just DDS
> signal noise?
>
>
>
> 73,
>
> James KC2UEE
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html

gm3sek

Re: K3 birdies - question?

In reply to this post by K2QI

James Sarte wrote:
>
>
>At first I thought I did not have any noticeable birdies, but now it
>seems that I have developed a few. It's probably from moving cables
>and such around inside the rig.
>
>

We could really use a detailed set of photos of cables behind the synth
board(s), showing the complete step-by-step buildup of a good layout -
and also examples showing what *not* to do.

--

73 from Ian GM3SEK
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David Cutter

Re: K3 birdies - question?

I also wonder if it would be worthwhile buying higher spec coax. Don't know what is used in the K3, but for the lengths involved it would be worth the investment to get short cables made in say LMR100 or RG142 etc if it's not already

David
G3UNA

---- Ian White GM3SEK <[hidden email]> wrote:

> James Sarte wrote:
> >
> >
> >At first I thought I did not have any noticeable birdies, but now it
> >seems that I have developed a few. It's probably from moving cables
> >and such around inside the rig.
> >
> >
>
> We could really use a detailed set of photos of cables behind the synth
> board(s), showing the complete step-by-step buildup of a good layout -
> and also examples showing what *not* to do.
>
>
>
> --
>
> 73 from Ian GM3SEK
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html

K2QI

Re: K3 birdies - question?

In reply to this post by Grant Youngman

Hello Grant,

There are some that are strong enough that when the antenna is removed, they
can still be heard a little bit above the noise floor. For the most part
however, removing the antenna or changing over to the dummy load removes or
masks them completely.

It really does sound like some sort of synth noise, but I can't explain its
behavior with the antenna. They are always in the same places, and when you
tune up or down the band, the tones will change in pitch until you pass a
certain frequency.

73,
James KC2UEE

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Grant Youngman
Sent: Wednesday, March 04, 2009 1:08 AM
To: Elecraft Mailing List
Subject: Re: [Elecraft] K3 birdies - question?

What you're hearing aren't "birdies". If they go away when you remove
the antenna, then obviously they're signals being picked up by the
antenna from some source outside the radio. Do you her them on
another receiver connected to the same antenna?

Grant/NQ5T

On Mar 3, 2009, at 11:22 PM, James Sarte wrote:

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--... ...-- -.. . .--- .- -- . ...

Richard Ferch

Re: K3 birdies - question?

In reply to this post by K2QI

James,

Any signal coming in from the antenna will change pitch when you tune the
radio in CW, SSB or DATA mode. That's not how you tell a birdie from a real
signal - it's removing the antenna that distinguishes them. A real signal
will either disappear entirely or at least become much weaker when the
antenna is removed. Internal birdies, on the other hand, usually sound
louder when the antenna is removed, because the noise floor surrounding them
drops.

Note also that there is a difference between the situation with nothing
connected to any of the K3's antenna connectors, and having anything at all,
such as an antenna switch or a dummy load or just a short piece of coax,
connected to one of the connectors. If the signal is still there with
nothing whatsoever touching any of the antenna connectors, then it is likely
a birdie internal to the radio. From your description, it sounds as if you
are hearing external signals, not birdies.

There are different kinds of birdies. Some are on fixed frequencies, just
like real signals, and others are harmonics that tune more rapidly than real
signals. The birdies that are removed by the new signal removal feature are
the ones that change pitch abnormally rapidly as you tune the radio.

With a real signal, if you change the receiver's frequency by 10 Hz, the
pitch of the signal changes by 10 Hz. With one of these "fast" birdies,
changing the tuning of the radio by 10 Hz might cause the pitch of the
birdie to change by 300 Hz. These "fast" birdies also change pitch when you
rotate the Shift control - real signals do not.

Using a 2.7 kHz roofing filter, as you tune past a real signal it will be
audible over a tuning range of about 2.7 kHz, and will sweep steadily from
very low to very high pitch (or vice versa) as you tune past it. In
contrast, a "fast" birdie might only be audible over a tuning range of about
100 Hz, i.e. as you tune the radio past the birdie it will jump right across
the audible range of pitches within only 100 Hz of dial movement. These are
the birdies that the signal removal feature works on. It doesn't work on
birdies that are on fixed frequencies and tune like real signals.

73,
Rich VE3KI

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AC7AC

Re: K3 birdies - question?

In reply to this post by gm3sek

CONTENTS DELETED

The author has deleted this message.

K2QI

Re: K3 birdies - question?

In reply to this post by Richard Ferch

Rich,

Many thanks for your reply.

>From your description, it then sounds as if I'm hearing a real signal. I do
have a theory that there may be some sort of electronic signal getting into
my feedline. My coax isn't routed ideally, as a good portion of it runs
between two entertainment centers chock full of transformers, etc.

These birdies or signals as I hear them change in pitch over a wide range,
not just 100Hz. For example, if I start at 28.375, I can hear a solid
tone. As I go to 28.376, the tone pitch increases and so on until it peaks
at 28.380. At 28.381, I can no longer hear it. If I go back down in
frequency, the pattern repeats itself with the tone pitch decreasing.

I seem to hear these "birdies" spaced every 500-700 KHz. I'm going by
memory now as I don't have the rig in front of me.

If I remove the antenna, most of them go away. When I say most, I'd guess
about 98% of them. Only some which are very strong are still barely
audible, but their behavior doesn't change as I tune around. They are not
by your description fast tuning.

With the antenna connected, the loudest of these signals will peak my
S-meter at S3. With no antenna, it may be an S0-S1.

Interestingly, removing the antenna does not affect the sub receiver as I
can still hear them a little bit when the sub is set to ANT1. Switching the
sub to the BNC though, and all remaining signals disappear.

I'll have to play around a little bit more to determine the origin, but I
was surprised to suddenly hear all of these signals spaced quite evenly
apart. I began to think that this was synthesizer noise, as it does sound
similar to the DDS signals. I remember telling Wayne over the phone that I
was pleasantly surprised after the build, because the first thing I did was
to tune around the entire frequency range with no antenna attached to test
for birdies, and I did not hear any at all.

73,
James KC2UEE

On Wed, Mar 4, 2009 at 10:07 AM, Richard Ferch <[hidden email]> wrote:

> James,
>
> Any signal coming in from the antenna will change pitch when you tune the
> radio in CW, SSB or DATA mode. That's not how you tell a birdie from a real
> signal - it's removing the antenna that distinguishes them. A real signal
> will either disappear entirely or at least become much weaker when the
> antenna is removed. Internal birdies, on the other hand, usually sound
> louder when the antenna is removed, because the noise floor surrounding
> them
> drops.
>
> Note also that there is a difference between the situation with nothing
> connected to any of the K3's antenna connectors, and having anything at
> all,
> such as an antenna switch or a dummy load or just a short piece of coax,
> connected to one of the connectors. If the signal is still there with
> nothing whatsoever touching any of the antenna connectors, then it is
> likely
> a birdie internal to the radio. From your description, it sounds as if you
> are hearing external signals, not birdies.
>
> There are different kinds of birdies. Some are on fixed frequencies, just
> like real signals, and others are harmonics that tune more rapidly than
> real
> signals. The birdies that are removed by the new signal removal feature are
> the ones that change pitch abnormally rapidly as you tune the radio.
>
> With a real signal, if you change the receiver's frequency by 10 Hz, the
> pitch of the signal changes by 10 Hz. With one of these "fast" birdies,
> changing the tuning of the radio by 10 Hz might cause the pitch of the
> birdie to change by 300 Hz. These "fast" birdies also change pitch when you
> rotate the Shift control - real signals do not.
>
> Using a 2.7 kHz roofing filter, as you tune past a real signal it will be
> audible over a tuning range of about 2.7 kHz, and will sweep steadily from
> very low to very high pitch (or vice versa) as you tune past it. In
> contrast, a "fast" birdie might only be audible over a tuning range of
> about
> 100 Hz, i.e. as you tune the radio past the birdie it will jump right
> across
> the audible range of pitches within only 100 Hz of dial movement. These are
> the birdies that the signal removal feature works on. It doesn't work on
> birdies that are on fixed frequencies and tune like real signals.
>
> 73,
> Rich VE3KI
>
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

--... ...-- -.. . .--- .- -- . ...

gm3sek

Re: K3 birdies - question?

In reply to this post by AC7AC

Ron D'Eau Claire wrote:

>I've had the cables all over the place. There seems to be only one
>cable whose placement has a significant effect on birdies. That's the
>long (10"/25cm)cable running from J84 at the bottom of the Auxiliary
>KSYN3 board to J85 on the KRX3 RF module. It should be dressed as shown
>in Figure 47 in the KRX3 manual. In some cases it helps to keep it away
>from the tiny toriods on the mixer board as well. Either run it across
>above the mixer board as shown or work it down under the mixer board so
>it loops up between the mixer board and the front panel shield to J85
>on the KRX3 RF module.
>

Thanks, Ron.

--

73 from Ian GM3SEK
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n6wg

Re: K3 birdies - question?

In reply to this post by K2QI

James
When you start looking around for sources of these external
signals, be prepared for some surprises. I had a fairly
strong signal on 10m that was a real nuisance. I turned
off the power to my house and it went away. I finally
found it in the controller for our air mattress in the
bedroom. Now, during a serious 10m effort, like the
ARRL 10m contest, I just unplug the controller until after
the contest.
73, Bob N6WG

----- Original Message -----
From: "KC2UEE" <[hidden email]>
To: "Richard Ferch" <[hidden email]>
Cc: <[hidden email]>
Sent: Wednesday, March 04, 2009 8:15 AM
Subject: Re: [Elecraft] K3 birdies - question?

> Rich,
>
> Many thanks for your reply.
>
>>From your description, it then sounds as if I'm hearing a real signal. I
>>do
> have a theory that there may be some sort of electronic signal getting
> into
> my feedline. My coax isn't routed ideally, as a good portion of it runs
> between two entertainment centers chock full of transformers, etc.
>
> These birdies or signals as I hear them change in pitch over a wide range,
> not just 100Hz. For example, if I start at 28.375, I can hear a solid
> tone. As I go to 28.376, the tone pitch increases and so on until it
> peaks
> at 28.380. At 28.381, I can no longer hear it. If I go back down in
> frequency, the pattern repeats itself with the tone pitch decreasing.
>
> I seem to hear these "birdies" spaced every 500-700 KHz. I'm going by
> memory now as I don't have the rig in front of me.
>
> If I remove the antenna, most of them go away. When I say most, I'd guess
> about 98% of them. Only some which are very strong are still barely
> audible, but their behavior doesn't change as I tune around. They are not
> by your description fast tuning.
>
> With the antenna connected, the loudest of these signals will peak my
> S-meter at S3. With no antenna, it may be an S0-S1.
>
> Interestingly, removing the antenna does not affect the sub receiver as I
> can still hear them a little bit when the sub is set to ANT1. Switching
> the
> sub to the BNC though, and all remaining signals disappear.
>
> I'll have to play around a little bit more to determine the origin, but I
> was surprised to suddenly hear all of these signals spaced quite evenly
> apart. I began to think that this was synthesizer noise, as it does sound
> similar to the DDS signals. I remember telling Wayne over the phone that
> I
> was pleasantly surprised after the build, because the first thing I did
> was
> to tune around the entire frequency range with no antenna attached to test
> for birdies, and I did not hear any at all.
>
> 73,
> James KC2UEE
>
>
>
>
> On Wed, Mar 4, 2009 at 10:07 AM, Richard Ferch <[hidden email]> wrote:
>
>> James,
>>
>> Any signal coming in from the antenna will change pitch when you tune the
>> radio in CW, SSB or DATA mode. That's not how you tell a birdie from a
>> real
>> signal - it's removing the antenna that distinguishes them. A real signal
>> will either disappear entirely or at least become much weaker when the
>> antenna is removed. Internal birdies, on the other hand, usually sound
>> louder when the antenna is removed, because the noise floor surrounding
>> them
>> drops.
>>
>> Note also that there is a difference between the situation with nothing
>> connected to any of the K3's antenna connectors, and having anything at
>> all,
>> such as an antenna switch or a dummy load or just a short piece of coax,
>> connected to one of the connectors. If the signal is still there with
>> nothing whatsoever touching any of the antenna connectors, then it is
>> likely
>> a birdie internal to the radio. From your description, it sounds as if
>> you
>> are hearing external signals, not birdies.
>>
>> There are different kinds of birdies. Some are on fixed frequencies, just
>> like real signals, and others are harmonics that tune more rapidly than
>> real
>> signals. The birdies that are removed by the new signal removal feature
>> are
>> the ones that change pitch abnormally rapidly as you tune the radio.
>>
>> With a real signal, if you change the receiver's frequency by 10 Hz, the
>> pitch of the signal changes by 10 Hz. With one of these "fast" birdies,
>> changing the tuning of the radio by 10 Hz might cause the pitch of the
>> birdie to change by 300 Hz. These "fast" birdies also change pitch when
>> you
>> rotate the Shift control - real signals do not.
>>
>> Using a 2.7 kHz roofing filter, as you tune past a real signal it will be
>> audible over a tuning range of about 2.7 kHz, and will sweep steadily
>> from
>> very low to very high pitch (or vice versa) as you tune past it. In
>> contrast, a "fast" birdie might only be audible over a tuning range of
>> about
>> 100 Hz, i.e. as you tune the radio past the birdie it will jump right
>> across
>> the audible range of pitches within only 100 Hz of dial movement. These
>> are
>> the birdies that the signal removal feature works on. It doesn't work on
>> birdies that are on fixed frequencies and tune like real signals.
>>
>> 73,
>> Rich VE3KI
>>
>>
>>
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html

K2QI

Re: K3 birdies - question?

In reply to this post by AC7AC

That particular TMP cable I have running underneath the KRX3 board, and over
the filters.

73,
James KC2UEE

On Wed, Mar 4, 2009 at 11:01 AM, Ron D'Eau Claire <[hidden email]> wrote:

> I've had the cables all over the place. There seems to be only one cable
> whose placement has a significant effect on birdies. That's the long
> (10"/25cm)cable running from J84 at the bottom of the Auxiliary KSYN3 board
> to J85 on the KRX3 RF module. It should be dressed as shown in Figure 47 in
> the KRX3 manual. In some cases it helps to keep it away from the tiny
> toriods on the mixer board as well. Either run it across above the mixer
> board as shown or work it down under the mixer board so it loops up between
> the mixer board and the front panel shield to J85 on the KRX3 RF module.
>
> Ron AC7AC
>
> -----Original Message-----
> From: [hidden email]
> [mailto:[hidden email]] On Behalf Of Ian White GM3SEK
> Sent: Wednesday, March 04, 2009 12:11 AM
> To: [hidden email]
> Subject: Re: [Elecraft] K3 birdies - question?
>
> James Sarte wrote:
> >
> >
> >At first I thought I did not have any noticeable birdies, but now it
> >seems that I have developed a few. It's probably from moving cables
> >and such around inside the rig.
> >
> >
>
> We could really use a detailed set of photos of cables behind the synth
> board(s), showing the complete step-by-step buildup of a good layout -
> and also examples showing what *not* to do.
>
>
>
> --
>
> 73 from Ian GM3SEK
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

--... ...-- -.. . .--- .- -- . ...

Dave Van Wallaghen

Re: K3 birdies - question?

James,

I wound up running that one on top to diminish some of the birdies I had. In fact it almost eliminated most of them even with the antenna off and they ate certainly undetectable with the antenna connected.

73,
Dave W8FGU
-----Original Message-----
From: KC2UEE <[hidden email]>

Date: Wed, 4 Mar 2009 12:53:23
To: Ron D'Eau Claire<[hidden email]>
Cc: <[hidden email]>
Subject: Re: [Elecraft] K3 birdies - question?

That particular TMP cable I have running underneath the KRX3 board, and over
the filters.

73,
James KC2UEE

On Wed, Mar 4, 2009 at 11:01 AM, Ron D'Eau Claire <[hidden email]> wrote:

______________________________________________________________
Elecraft mailing list
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Post: mailto:[hidden email]

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Please help support this email list: http://www.qsl.net/donate.html
______________________________________________________________
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Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

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Please help support this email list: http://www.qsl.net/donate.html

K2QI

Re: K3 birdies - question?

In reply to this post by K2QI

Aha! I think you're on to something here Bill.

My RG-8 actually snakes its away around one of my entertainment centers
where I happen to have a cable modem, network switch, and seperate wireless
router all in the same spot. I have a PS3, Xbox360, and an Onkyo TX-NR905
receiver all wired by CAT-5 into the switch, plus the wireless router also
wired into the switch is only a few inches away. The RG-8 runs behind all
of that stuff, and if I recall, I simply have the cat5 cable laying loosely
around it. There also happens to be several wall-wart transformers behind
the entertainment center, which I'm sure aren't helping the situation.

When I get home, I'll try and turn off the network devices and see what
happens.

Like you, I'm also a computer geek hihi. I've got 2 home built PC's, a
Mac tower, and 3 laptops floating around the house all networked wirelessly.

It never crossed my mind to check the network for EMI... thanks again for
the suggestion!

73,
James KC2UEE

On Wed, Mar 4, 2009 at 1:07 PM, William Evans <[hidden email]> wrote:

> James,
> I believe what you are hearing are harmonics from ethernet cables. I
> listened on 28.380, and sure enough, I heard one of the tones there also
> which go away when I complete shield the antenna (dummy load) or remove it
> completely. I have been meaning to do something about these numerous
> network induced tones for a long time, but I haven't gotten around to it
> since they affect the higher frequencies the most (i.e., the "quieter
> bands"). Toroids and lots of shielding on all ethernet cables are required,
> and I have my whole house wired (about 6 computers, plus various routers,
> wi-fi, etc. Often the switching power supplies for these units generate a
> lot of noise.)
>
> Bill
> W4ISH
>
>

--... ...-- -.. . .--- .- -- . ...

Joe Planisky

Re: K3 birdies - question?

I find a portable (i.e. battery powered) short wave receiver very
useful for tracking down local sources of EMI. When I hear EMI that
goes away when I remove the antenna on my K3, I get out my SWL
receiver and tune it to the same frequency so I can hear the EMI on
it. With the telescoping whip antenna partially extended, I walk
around the house, placing the tip of the whip near suspected devices.
It's usually very obvious when you find the emitter as the signal
rapidly gets louder as you get close. I then make a note in my
logbook of the frequency and the offending device so I know exactly
which gadget to turn off if the need arises (assuming I can't easily
fix the device.)

It's a little less disruptive than switching off circuit breakers.

73
--
Joe KB8AP

On Mar 4, 2009, at 10:35 AM, KC2UEE wrote:

> Aha! I think you're on to something here Bill.
>
> My RG-8 actually snakes its away around one of my entertainment
> centers
> where I happen to have a cable modem, network switch, and seperate
> wireless
> router all in the same spot. I have a PS3, Xbox360, and an Onkyo TX-
> NR905
> receiver all wired by CAT-5 into the switch, plus the wireless
> router also
> wired into the switch is only a few inches away. The RG-8 runs
> behind all
> of that stuff, and if I recall, I simply have the cat5 cable laying
> loosely
> around it. There also happens to be several wall-wart transformers
> behind
> the entertainment center, which I'm sure aren't helping the situation.
>
> When I get home, I'll try and turn off the network devices and see
> what
> happens.
>
> Like you, I'm also a computer geek hihi. I've got 2 home built
> PC's, a
> Mac tower, and 3 laptops floating around the house all networked
> wirelessly.
>
> It never crossed my mind to check the network for EMI... thanks
> again for
> the suggestion!
>
> 73,
> James KC2UEE

K2QI

Re: K3 birdies - question?

Hi Joe and gang,

I found the source of my "birdie"... ended up being a Linksys 54g wireless
router running a custom Linux kernel. The second I unplugged it from the
mains, all noise dissipated on the K3. Amazing really that it was so easy
to find! Special thanks to Bill W4ISH for pointing me in the right
direction.

Anyway, any suggestions on isolating my feedline? Would ferrite chokes on
the RG-8 work? I can't unplug the router for long periods of time as other
machines in my house require a constant network connection.

73,
James KC2UEE

-----Original Message-----
From: Joe Planisky [mailto:[hidden email]]
Sent: Wednesday, March 04, 2009 2:01 PM
To: KC2UEE
Cc: Elecraft list
Subject: Re: [Elecraft] K3 birdies - question?

I find a portable (i.e. battery powered) short wave receiver very
useful for tracking down local sources of EMI. When I hear EMI that
goes away when I remove the antenna on my K3, I get out my SWL
receiver and tune it to the same frequency so I can hear the EMI on
it. With the telescoping whip antenna partially extended, I walk
around the house, placing the tip of the whip near suspected devices.
It's usually very obvious when you find the emitter as the signal
rapidly gets louder as you get close. I then make a note in my
logbook of the frequency and the offending device so I know exactly
which gadget to turn off if the need arises (assuming I can't easily
fix the device.)

It's a little less disruptive than switching off circuit breakers.

73
--
Joe KB8AP

On Mar 4, 2009, at 10:35 AM, KC2UEE wrote:

--... ...-- -.. . .--- .- -- . ...

Vic K2VCO

Re: K3 birdies - question?

James Sarte wrote:

> Hi Joe and gang,
>
> I found the source of my "birdie"... ended up being a Linksys 54g wireless
> router running a custom Linux kernel. The second I unplugged it from the
> mains, all noise dissipated on the K3. Amazing really that it was so easy
> to find! Special thanks to Bill W4ISH for pointing me in the right
> direction.
>
> Anyway, any suggestions on isolating my feedline? Would ferrite chokes on
> the RG-8 work? I can't unplug the router for long periods of time as other
> machines in my house require a constant network connection.

The coax may be getting noise from the router and cables on the outside of the braid. This
then flows up to the antenna, where it is picked up. A coaxial choke or balun at the
antenna end of the coax might help.
--
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco
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w0mu

Re: K3 birdies - question?

In reply to this post by K2QI

Yes subscribe to [hidden email] and search those archives. Routers and
switches and hubs are notorious for generating crud.

"A slip of the foot you may soon recover, but a slip of the tongue you may
never get over." Ben Franklin
-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of James Sarte
Sent: Wednesday, March 04, 2009 4:58 PM
To: 'Joe Planisky'; 'KC2UEE'
Cc: 'Elecraft list'
Subject: Re: [Elecraft] K3 birdies - question?

Hi Joe and gang,

I found the source of my "birdie"... ended up being a Linksys 54g wireless
router running a custom Linux kernel. The second I unplugged it from the
mains, all noise dissipated on the K3. Amazing really that it was so easy
to find! Special thanks to Bill W4ISH for pointing me in the right
direction.

Anyway, any suggestions on isolating my feedline? Would ferrite chokes on
the RG-8 work? I can't unplug the router for long periods of time as other
machines in my house require a constant network connection.

73,
James KC2UEE

-----Original Message-----
From: Joe Planisky [mailto:[hidden email]]
Sent: Wednesday, March 04, 2009 2:01 PM
To: KC2UEE
Cc: Elecraft list
Subject: Re: [Elecraft] K3 birdies - question?

I find a portable (i.e. battery powered) short wave receiver very useful for
tracking down local sources of EMI. When I hear EMI that goes away when I
remove the antenna on my K3, I get out my SWL receiver and tune it to the
same frequency so I can hear the EMI on
it. With the telescoping whip antenna partially extended, I walk
around the house, placing the tip of the whip near suspected devices.
It's usually very obvious when you find the emitter as the signal rapidly
gets louder as you get close. I then make a note in my logbook of the
frequency and the offending device so I know exactly which gadget to turn
off if the need arises (assuming I can't easily fix the device.)

It's a little less disruptive than switching off circuit breakers.

73
--
Joe KB8AP

On Mar 4, 2009, at 10:35 AM, KC2UEE wrote:

> Aha! I think you're on to something here Bill.
>
> My RG-8 actually snakes its away around one of my entertainment
> centers where I happen to have a cable modem, network switch, and
> seperate wireless router all in the same spot. I have a PS3, Xbox360,
> and an Onkyo TX-
> NR905
> receiver all wired by CAT-5 into the switch, plus the wireless router
> also wired into the switch is only a few inches away. The RG-8 runs
> behind all of that stuff, and if I recall, I simply have the cat5
> cable laying loosely around it. There also happens to be several
> wall-wart transformers behind the entertainment center, which I'm sure
> aren't helping the situation.
>
> When I get home, I'll try and turn off the network devices and see
> what happens.
>
> Like you, I'm also a computer geek hihi. I've got 2 home built PC's,
> a Mac tower, and 3 laptops floating around the house all networked
> wirelessly.
>
> It never crossed my mind to check the network for EMI... thanks again
> for the suggestion!
>
> 73,
> James KC2UEE

David Gilbert

Re: K3 birdies - question?

In reply to this post by AC7AC

I've played around extensively with the cables in the K3 to see what
worked best, and as others (including Wayne) have noted, cable positions
that minimize one birdie might be poor for another. I'm convinced it
also makes a big difference whether or not you have the KRX3 subreceiver
installed, and I suspect that some signals are being conducted by the
shield of the KRX3 itself. I can short the top of the KRX3 shield to
the chassis at its far rear corner (looking from the front of the rig)
and cut the strength of several birdies in half.

I agree with Ron, though, that routing the cable to J85 on the KRX3 is
best done under the mixer board ... that made a large difference on
certain birdies without adversely affecting others that I could tell.

The other cable that seemed to have a big impact for me is the one going
from J2 on the KREF3 board to J83 on the KSYN3 board. Some birdies are
weakest when that cable is pressed down closer to the main RF board, but
it makes others stronger. Most of the birdies are weaker when that
cable is positioned just barely on top of the KRX3 shield ... running
along the front corner as closely as possible for as far as possible. I
noticed while playing around with that cable that if I held it between
the thumb and index finger of each hand that I could almost totally mute
certain birdies that were otherwise a solid S-2. So, in an experiment
I'm somewhat embarrassed to acknowledge, I placed 4" x 6" sheets of 1/8
inch thick high density conductive anti-static foam inside zip-lock
sandwich bags (to avoid shorting anything in the K3) and tried to
isolate that and other cables from each other and from various parts of
the K3 with what I thought might be lossy shielding at UHF frequencies.
Rolling up some of the foam into about a one inch diameter roll and
placing it between the cable going to J2 of the KREF3 board and the
KREF3 board itself significantly cut several 40m birdies down in
strength, but it didn't affect the S-3 one at 7259.48 at all. I
abandoned the foam and repositioned the cable along the front edge of
the KRX3 shield.

One thing I noticed, though, was that the can for the KTCXO (plugged
into a socket on the KREF3 board) was extremely sensitive. If I touched
it with my finger the strength of the birdies increased dramatically. I
assume the can is supposed to provide shielding and is probably grounded
via one of its pins, but it sits pretty far off the socket and I'm
wondering whether it shouldn't be more effectively bonded to ground. I
built a K2 several years ago and if I remember correctly the
instructions required that the cans of the crystals be grounded with
wires that I soldered to them. I'd be willing to try bonding the can of
the KTCXO to ground with some sort of clip if anyone from Elecraft can
tell me that I won't ruin something doing so.

I've had the chance to beta test the SIG RMV birdie removal software and
I find it works very well. I purposely left a half dozen birdies
untreated so that I could check out other potential remedies such as the
(ahem) conductive foam, but at this point I've gone back and zapped them
with SIG RMV and I'm happy with that. My advice to others would be to
position the cables as best you can per the descriptions that have been
given by others here on the reflector, and then use SIG RMV to finish
the job when it becomes universally available. Since SIG RMV alters the
frequency of the birdie itself as you tune across it, it totally removes
the birdie ... it doesn't just weaken it. It's a very clever piece of
engineering.

If anyone is interested in seeing my cable routing as a starting point,
the links below might help. I make no claim whatsoever that they will
work for anyone else.

http://i228.photobucket.com/albums/ee141/xazdave/K3CableRouting1.jpg

http://i228.photobucket.com/albums/ee141/xazdave/K3CableRouting2.jpg

73,
Dave AB7E

Ron D'Eau Claire wrote:

Geoffrey Mackenzie-Kennedy

Re: K3 birdies - question?

In reply to this post by David Cutter

David,

Double shielded coax would certainly reduce leakage from the coax, and is a
good investment in my opinion. However its use might not have too much
impact on the receiver's birdie problem, because many of the "rogue" signals
involved are probably flowing on the outside of the coax's braid, certainly
if the coax emerges from some enclosure through a hole.

The usual cause of a receiver birdie is that some response of the receiver
is "hearing" some oscillator or a harmonic, or some mixing product of two or
more oscillators, contained within the receiver. In a down conversion HF
receiver, the great majority of the receiver's responses, therefore the
"rogue signals", that cause birdie problems are at HF and up to low/ mid
VHF, which means that choking off coax runs within a receiver becomes
cumbersome.

73,

Geoff
GM4ESD

David Cutter wrote on Wednesday, March 04, 2009, at 10:32 AM:

>I also wonder if it would be worthwhile buying higher spec coax. Don't
>know what is used in the K3, but for the lengths involved it would be worth
>the investment to get short cables made in say LMR100 or RG142 etc if it's
>not already
>
> David
> G3UNA

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David Cutter

Re: K3 birdies - question?

So, could we use the good old methods of wrapping the coax around a suitable toroid. That would mean a longer cable at which point I would invest in a better quality cable if I were doing it and I'm tempted to do so to get the best chance of cracking the main issues we are addressing.

David
G3UNA

---- Geoffrey Mackenzie-Kennedy <[hidden email]> wrote:

> David,
>
> Double shielded coax would certainly reduce leakage from the coax, and is a
> good investment in my opinion. However its use might not have too much
> impact on the receiver's birdie problem, because many of the "rogue" signals
> involved are probably flowing on the outside of the coax's braid, certainly
> if the coax emerges from some enclosure through a hole.
>
> The usual cause of a receiver birdie is that some response of the receiver
> is "hearing" some oscillator or a harmonic, or some mixing product of two or
> more oscillators, contained within the receiver. In a down conversion HF
> receiver, the great majority of the receiver's responses, therefore the
> "rogue signals", that cause birdie problems are at HF and up to low/ mid
> VHF, which means that choking off coax runs within a receiver becomes
> cumbersome.
>
> 73,
>
> Geoff
> GM4ESD
>
> David Cutter wrote on Wednesday, March 04, 2009, at 10:32 AM:
>
> >I also wonder if it would be worthwhile buying higher spec coax. Don't
> >know what is used in the K3, but for the lengths involved it would be worth
> >the investment to get short cables made in say LMR100 or RG142 etc if it's
> >not already
> >
> > David
> > G3UNA
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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>
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