Zipper Noise and Birdies on 6M -- FIXED!

[Jim Brown-10]

Ever since I started using my K3 on 6M I've been troubled with zipper
noise as I tune, as well as birdies generated within the K3 that move
around as I tune.  Today I found and eliminated the coupling mechanism,
and the noise and birdies are gone.

My setup uses an external ARR 6M preamp at the RXOUT / RXIN patch point.
(I use it rather than the Elecraft preamp because I already owned it,
and it's a very good preamp). I also have a switch that brings in my
Beverages,  with a Tee jumper between the AUX input (for the SUB RX) and
the RXIN.  That Tee was the coupling path. On a hunch, I replaced the
Tee with a Mini-Circuits passive splitter that has about 35dB of
isolation between outputs, with an insertion loss of 6.6 dB.  It's rated
for use between 10 MHz and 1 GHz, but it passes my Beverages on 160M
just fine.

Mini-Circuits is an old line, well respected company based in Brooklyn.
I've been specifying their splitters for about 30 years for the VHF and
UHF wireless mic systems I designed for performance facilities and
churches.  The splitter I used with the K3 is a ZFSC-4-175 that is one
of several I picked up at a hamfest.  While it's a 75 ohm splitter, it
works just fine in this application.  It's a 4x1 splitter, and a 2x1
would work equally well.  For optimum isolation, unused outputs should
be terminated in 75 ohms, and I did that.

http://www.minicircuits.com/pdfs/ZFSC-4-175.pdf

http://www.minicircuits.com/pdfs/ZFSC-2-1+.pdf

El cheapo CATV splitters MAY also work -- IF they have enough isolation.

73, Jim Brown K9YC
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[Jim Brown-10]

On 7/3/2011 3:42 PM, Merv Schweigert wrote:
> Ever since I started using my K3 on 6M I've been troubled with zipper
> noise as I tune, as well as birdies generated within the K3 that move
> around as I tune.  Today I found and eliminated the coupling mechanism,
> and the noise and birdies are gone.

Sorry team, I spoke too soon.  Turns out the zipper noise was swamped by
band noise when I tested after making the change. It's still there, a
bit weaker. Most of the birdies are weaker, and a very loud one is gone.
So the isolation of the splitter helps, but is not a complete fix.

73, Jim K9YC

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[John_N1JM]

How old is your radio? Isn't there an Elecraft mod for that?

John N1JM

[Allen Brier N5XZ]

I have a number of birdies on 6 and other bands and they sure are annoying.
What's the best way to eliminate them? I am not using an external pre-amp.

Allen N5XZ

ORIGNAL MESSAGE:
Message: 20
Date: Sun, 03 Jul 2011 15:32:21 -0700
From: Jim Brown <[hidden email]>
Subject: [Elecraft] Zipper Noise and Birdies on 6M -- FIXED!
To: Reflector Elecraft <[hidden email]>
Message-ID: <[hidden email]>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

Ever since I started using my K3 on 6M I've been troubled with zipper
noise as I tune, as well as birdies generated within the K3 that move
around as I tune.  Today I found and eliminated the coupling mechanism,
and the noise and birdies are gone.

My setup uses an external ARR 6M preamp at the RXOUT / RXIN patch point.
(I use it rather than the Elecraft preamp because I already owned it,
and it's a very good preamp). I also have a switch that brings in my
Beverages,  with a Tee jumper between the AUX input (for the SUB RX) and
the RXIN.  That Tee was the coupling path. On a hunch, I replaced the
Tee with a Mini-Circuits passive splitter that has about 35dB of
isolation between outputs, with an insertion loss of 6.6 dB.  It's rated
for use between 10 MHz and 1 GHz, but it passes my Beverages on 160M
just fine.

Mini-Circuits is an old line, well respected company based in Brooklyn.
I've been specifying their splitters for about 30 years for the VHF and
UHF wireless mic systems I designed for performance facilities and
churches.  The splitter I used with the K3 is a ZFSC-4-175 that is one
of several I picked up at a hamfest.  While it's a 75 ohm splitter, it
works just fine in this application.  It's a 4x1 splitter, and a 2x1
would work equally well.  For optimum isolation, unused outputs should
be terminated in 75 ohms, and I did that.

http://www.minicircuits.com/pdfs/ZFSC-4-175.pdf

http://www.minicircuits.com/pdfs/ZFSC-2-1+.pdf

El cheapo CATV splitters MAY also work -- IF they have enough isolation.

73, Jim Brown K9YC

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[John Ragle]

Allen...

     I have these same birdies (at least I suppose they're the same) and
I suspect that all K3 have them. The most annoying ones are where the CW
action usually occurs (50.09430, 20 dB above noise floor) and a number
of minor ones around 50.098 (3-5 dB above the noise floor), as well as
several major ones up where the SSB action occurs: 50.21050, 50.24055,
etc. which are all 20+ dB above the noise floor. These are not
"external" blips (not computer, not router, etc.) as they are present
when nothing else is on, and they are present when the antenna is
disconnected.

     I "treat" them by ignoring them. They are sharp, stable, and
unmodulated. My ear can differentiate between them and real signals
without any problem. They are "features" for "calibration.".. ;>) Every
modern rig I have ever owned has had similar warts.

John Ragle -- W1ZI

=====

On 7/4/2011 1:16 PM, Allen R. Brier wrote:
> I have a number of birdies on 6 and other bands and they sure are annoying.
> What's the best way to eliminate them? I am not using an external pre-amp.
>
> Allen N5XZ

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[N5GE]

1. Go to page 59 of your owner's manual.
2. Near the top you will find a section labeled "SIG RMV [T]" ([T] means you
must have CONFIG in Test mode).
3. Follow the instructions.

And it works...

73,
Tom
Amateur Radio Operator N5GE
ARRL Lifetime Member
QCWA Lifetime Member



On Mon, 4 Jul 2011 12:16:21 -0500, "Allen R. Brier" <[hidden email]> wrote:

>I have a number of birdies on 6 and other bands and they sure are annoying.
>What's the best way to eliminate them? I am not using an external pre-amp.
>
>Allen N5XZ
>
[snip]

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[Mike Reublin]

Tech mode, not test mode.

73, Mike NF4L

On 7/4/2011 5:17 PM, [hidden email] wrote:

> 1. Go to page 59 of your owner's manual.
> 2. Near the top you will find a section labeled "SIG RMV [T]" ([T] means you
> must have CONFIG in Test mode).
> 3. Follow the instructions.
>
> And it works...
>
> 73,
> Tom
> Amateur Radio Operator N5GE
> ARRL Lifetime Member
> QCWA Lifetime Member
>
>
>
> On Mon, 4 Jul 2011 12:16:21 -0500, "Allen R. Brier"<[hidden email]>  wrote:
>
>> I have a number of birdies on 6 and other bands and they sure are annoying.
>> What's the best way to eliminate them? I am not using an external pre-amp.
>>
>> Allen N5XZ
>>
> [snip]
>
> ______________________________________________________________
> 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
>

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[John Ragle]

Try page 58 (not 59) & near bottom of page...or better yet, use the PDF
"find" resource for SIG RMV [T]...

John Ragle -- W1ZI

=====

On 7/5/2011 7:36 AM, Mike wrote:
> Tech mode, not test mode.
>
> 73, Mike NF4L
>
> On 7/4/2011 5:17 PM, [hidden email] wrote:
>> 1. Go to page 59 of your owner's manual.
>> 2. Near the top you will find a section labeled "SIG RMV [T]" ([T] means you
>> must have CONFIG in Test mode).
>> 3. Follow the instructions.
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[wa9fvp]

My K3 is 3 months old.  I don't hear any birdies on 6 meters with the antenna disconnedted.
I do hear birdies around the frequencies you mentioned but it's barely readable when antenna
is connected.