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6m birdies and K3S and/or new synth boards

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Dave G3WGN M6O

6m birdies and K3S and/or new synth boards

Is there anyone out there yet who has done a detailed study of 6m birdies with the new synth and either external or internal preamp? A good friend with an early K3 is reluctant to upgrade to K3S as he hears a couple of dozen birdies on 6m with antenna disconnected.

So how has this aspect of K3 performance evolved from early K3 (his is S/N sub-100) to the K3S?

David G3WGN M6O

Member of the 6Gs team at E6GG in September 2015 www.e6gg.com

Work us on as many bands as you can!

wayne burdick

Re: 6m birdies and K3S and/or new synth boards

Administrator

David,

When we designed the K3S, we very carefully evaluated internally generated spurs on all bands. We found that the KSYN3 and KSYN3A had roughly the same number. This is consistent with both being high-level signal sources; you can't get rid of spurs entirely. All but a very few are masked by band noise, as well.

6 meters was no exception. Both the old and new synths show some spurs on this band, and we adjusted PLL divider ratios, etc., to minimize them. But the new synth -- in our tests -- doesn't have any more than the old. I use a pair of the new synths in my lab K3S, as well as the KXV3B, which includes premamp 2 (-145 dB MDS). I've had no problem with spurs on 6 meters.

In some cases, it could come down to how the cables are oriented. Make sure you're orienting the cables as described in the manual, and if you feel that you have excessive spurs, email customer support. If we come up with any improved cable routing, we'll post to the list.

73,
Wayne
N6KR

On Jun 23, 2015, at 8:52 AM, Dave G3WGN M6O <[hidden email]> wrote:

> Is there anyone out there yet who has done a detailed study of 6m birdies with the new synth and either external or internal preamp? A good friend with an early K3 is reluctant to upgrade to K3S as he hears a couple of dozen birdies on 6m with antenna disconnected.
> So how has this aspect of K3 performance evolved from early K3 (his is S/N sub-100) to the K3S?
> 73
> David G3WGN M6O
> Member of the 6Gs team at E6GG in September 2015 www.e6gg.com<http://www.e6gg.com>
> Work us on as many bands as you can!
>
>
>
>
>
>
> --
> View this message in context: http://elecraft.365791.n2.nabble.com/6m-birdies-and-K3S-and-or-new-synth-boards-tp7604211.html
> Sent from the Elecraft mailing list archive at Nabble.com.
> ______________________________________________________________
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bhemmis

Re: 6m birdies and K3S and/or new synth boards

David, Your friend states there are 2 dozen birdies on 6 meters with the antenna DISCONNECTED. This tells me nothing. Please tell him to connect a RESONANT 6 meter antenna to the radio then tell me how many birdies he hears.
73, Brian K3USC

> On Jun 23, 2015, at 1:41 PM, Wayne Burdick <[hidden email]> wrote:
>
> David,
>
> When we designed the K3S, we very carefully evaluated internally generated spurs on all bands. We found that the KSYN3 and KSYN3A had roughly the same number. This is consistent with both being high-level signal sources; you can't get rid of spurs entirely. All but a very few are masked by band noise, as well.
>
> 6 meters was no exception. Both the old and new synths show some spurs on this band, and we adjusted PLL divider ratios, etc., to minimize them. But the new synth -- in our tests -- doesn't have any more than the old. I use a pair of the new synths in my lab K3S, as well as the KXV3B, which includes premamp 2 (-145 dB MDS). I've had no problem with spurs on 6 meters.
>
> In some cases, it could come down to how the cables are oriented. Make sure you're orienting the cables as described in the manual, and if you feel that you have excessive spurs, email customer support. If we come up with any improved cable routing, we'll post to the list.
>
> 73,
> Wayne
> N6KR
>
>
> On Jun 23, 2015, at 8:52 AM, Dave G3WGN M6O <[hidden email]> wrote:
>
>> Is there anyone out there yet who has done a detailed study of 6m birdies with the new synth and either external or internal preamp? A good friend with an early K3 is reluctant to upgrade to K3S as he hears a couple of dozen birdies on 6m with antenna disconnected.
>> So how has this aspect of K3 performance evolved from early K3 (his is S/N sub-100) to the K3S?
>> 73
>> David G3WGN M6O
>> Member of the 6Gs team at E6GG in September 2015 www.e6gg.com<http://www.e6gg.com>
>> Work us on as many bands as you can!
>>
>>
>>
>>
>>
>>
>> --
>> View this message in context: http://elecraft.365791.n2.nabble.com/6m-birdies-and-K3S-and-or-new-synth-boards-tp7604211.html
>> Sent from the Elecraft mailing list archive at Nabble.com.
>> ______________________________________________________________
>> 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
>> Message delivered to [hidden email]
>
> ______________________________________________________________
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Jim Brown-10

Re: 6m birdies and K3S and/or new synth boards

On Tue,6/23/2015 10:44 AM, Brian Hemmis wrote:
> David, Your friend states there are 2 dozen birdies on 6 meters with the antenna DISCONNECTED. This tells me nothing. Please tell him to connect a RESONANT 6 meter antenna to the radio then tell me how many birdies he hears.

It tells me a LOT. With no antenna connected and a 50 ohm resistor
across the antenna input, I hear birdies on 6M from my station logging
computer. That tells me that the K3 has a Pin One Problem on one or more
of the dozen or so connectors to which I have cables connected -- DC
power, Aux power out (for P3), audio I/O, mic, headphones, IF out to P3,
RX antenna in, AUX antenna in, paddle, amplifier key line, AUX cable,
and RS232 cable. With the antenna connected and pointed away from the
shack, these birdies are at least 6 dB above band noise when the band is
quiet.

This is in addition to the birdies generated within my K3s that move
around as the main RX is tuned. Interestingly, I do NOT see birdies
related to the SubRX. Those moving birdies are a real PITA -- I use the
P3 to look for weak CW signals during double-hop E-skip openings, and
those internally generated moving birdies look just like those weak CW
signals. This greatly reduces the usefulness of the P3 on 6M.
Installation of the new synth boards has not changed that. Although the
preamp in the KXV3B may have reduced my noise level a bit, I had an
outboard GasFET preamp before installing it, and heard the birdies with
it too.

73, Jim K9YC
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Guy Olinger K2AV

Re: 6m birdies and K3S and/or new synth boards

In reply to this post by bhemmis

Yes indeed. Checking for birdies or any such with an unterminated antenna
jack is invalid. You can terminate with a dummy load, or more practically
with an antenna listening to normal band noise.

73, Guy K2AV

On Tuesday, June 23, 2015, Brian Hemmis <[hidden email]> wrote:

> David, Your friend states there are 2 dozen birdies on 6 meters with the
> antenna DISCONNECTED. This tells me nothing. Please tell him to connect a
> RESONANT 6 meter antenna to the radio then tell me how many birdies he
> hears.
> 73, Brian K3USC
>
>
> > On Jun 23, 2015, at 1:41 PM, Wayne Burdick <[hidden email]
> <javascript:;>> wrote:
> >
> > David,
> >
> > When we designed the K3S, we very carefully evaluated internally
> generated spurs on all bands. We found that the KSYN3 and KSYN3A had
> roughly the same number. This is consistent with both being high-level
> signal sources; you can't get rid of spurs entirely. All but a very few are
> masked by band noise, as well.
> >
> > 6 meters was no exception. Both the old and new synths show some spurs
> on this band, and we adjusted PLL divider ratios, etc., to minimize them.
> But the new synth -- in our tests -- doesn't have any more than the old. I
> use a pair of the new synths in my lab K3S, as well as the KXV3B, which
> includes premamp 2 (-145 dB MDS). I've had no problem with spurs on 6
> meters.
> >
> > In some cases, it could come down to how the cables are oriented. Make
> sure you're orienting the cables as described in the manual, and if you
> feel that you have excessive spurs, email customer support. If we come up
> with any improved cable routing, we'll post to the list.
> >
> > 73,
> > Wayne
> > N6KR
> >
> >
> > On Jun 23, 2015, at 8:52 AM, Dave G3WGN M6O <[hidden email]
> <javascript:;>> wrote:
> >
> >> Is there anyone out there yet who has done a detailed study of 6m
> birdies with the new synth and either external or internal preamp? A good
> friend with an early K3 is reluctant to upgrade to K3S as he hears a couple
> of dozen birdies on 6m with antenna disconnected.
> >> So how has this aspect of K3 performance evolved from early K3 (his is
> S/N sub-100) to the K3S?
> >> 73
> >> David G3WGN M6O
> >> Member of the 6Gs team at E6GG in September 2015 www.e6gg.com<
> http://www.e6gg.com>
> >> Work us on as many bands as you can!
> >>
> >>
> >>
> >>
> >>
> >>
> >> --
> >> View this message in context:
> http://elecraft.365791.n2.nabble.com/6m-birdies-and-K3S-and-or-new-synth-boards-tp7604211.html
> >> Sent from the Elecraft mailing list archive at Nabble.com.
> >> ______________________________________________________________
> >> Elecraft mailing list
> >> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> >> Help: http://mailman.qth.net/mmfaq.htm
> >> Post: mailto:[hidden email] <javascript:;>
> >>
> >> This list hosted by: http://www.qsl.net
> >> Please help support this email list: http://www.qsl.net/donate.html
> >> Message delivered to [hidden email] <javascript:;>
> >
> > ______________________________________________________________
> > Elecraft mailing list
> > Home: http://mailman.qth.net/mailman/listinfo/elecraft
> > Help: http://mailman.qth.net/mmfaq.htm
> > Post: mailto:[hidden email] <javascript:;>
> >
> > This list hosted by: http://www.qsl.net
> > Please help support this email list: http://www.qsl.net/donate.html
> > Message delivered to [hidden email] <javascript:;>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email] <javascript:;>
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email] <javascript:;>
>

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Dave G3WGN M6O

Re: 6m birdies and K3S and/or new synth boards

In reply to this post by wayne burdick

Thanks Wayne, that's helpful. Just want to be sure I've optimised 6m performance and passed on any suggestions to my buddy.
73 David G3WGN

Sent from my Samsung smart (ish) phone

-------- Original message --------
From: Wayne Burdick <[hidden email]>
Date: 23/06/2015 19:39 (GMT+01:00)
To: David Aslin G3WGN <[hidden email]>
Cc: [hidden email]
Subject: Re: [Elecraft] 6m birdies and K3S and/or new synth boards

David,

When we designed the K3S, we very carefully evaluated internally generated spurs on all bands. We found that the KSYN3 and KSYN3A had roughly the same number. This is consistent with both being high-level signal sources; you can't get rid of spurs entirely. All but a very few are masked by band noise, as well.

6 meters was no exception. Both the old and new synths show some spurs on this band, and we adjusted PLL divider ratios, etc., to minimize them. But the new synth -- in our tests -- doesn't have any more than the old. I use a pair of the new synths in my lab K3S, as well as the KXV3B, which includes premamp 2 (-145 dB MDS). I've had no problem with spurs on 6 meters.

In some cases, it could come down to how the cables are oriented. Make sure you're orienting the cables as described in the manual, and if you feel that you have excessive spurs, email customer support. If we come up with any improved cable routing, we'll post to the list.

73,
Wayne
N6KR

On Jun 23, 2015, at 8:52 AM, Dave G3WGN M6O <[hidden email]> wrote:

Dave G3WGN M6O

Re: 6m birdies and K3S and/or new synth boards

In reply to this post by Guy Olinger K2AV

Got it.
73 David G3WGN

Sent from my Samsung device

-------- Original message --------
From: Guy Olinger K2AV <[hidden email]>
Date: 23/06/2015 20:16 (GMT+01:00)
To: Brian Hemmis <[hidden email]>
Cc: Wayne Burdick <[hidden email]>, [hidden email], David Aslin G3WGN <[hidden email]>
Subject: Re: [Elecraft] 6m birdies and K3S and/or new synth boards

Yes indeed. Checking for birdies or any such with an unterminated antenna jack is invalid. You can terminate with a dummy load, or more practically with an antenna listening to normal band noise.

73, Guy K2AV

On Tuesday, June 23, 2015, Brian Hemmis <[hidden email]<mailto:[hidden email]>> wrote:
David, Your friend states there are 2 dozen birdies on 6 meters with the antenna DISCONNECTED. This tells me nothing. Please tell him to connect a RESONANT 6 meter antenna to the radio then tell me how many birdies he hears.
73, Brian K3USC

> On Jun 23, 2015, at 1:41 PM, Wayne Burdick <[hidden email]> wrote:
>
> David,
>
> When we designed the K3S, we very carefully evaluated internally generated spurs on all bands. We found that the KSYN3 and KSYN3A had roughly the same number. This is consistent with both being high-level signal sources; you can't get rid of spurs entirely. All but a very few are masked by band noise, as well.
>
> 6 meters was no exception. Both the old and new synths show some spurs on this band, and we adjusted PLL divider ratios, etc., to minimize them. But the new synth -- in our tests -- doesn't have any more than the old. I use a pair of the new synths in my lab K3S, as well as the KXV3B, which includes premamp 2 (-145 dB MDS). I've had no problem with spurs on 6 meters.
>
> In some cases, it could come down to how the cables are oriented. Make sure you're orienting the cables as described in the manual, and if you feel that you have excessive spurs, email customer support. If we come up with any improved cable routing, we'll post to the list.
>
> 73,
> Wayne
> N6KR
>
>
> On Jun 23, 2015, at 8:52 AM, Dave G3WGN M6O <[hidden email]> wrote:
>
>> Is there anyone out there yet who has done a detailed study of 6m birdies with the new synth and either external or internal preamp? A good friend with an early K3 is reluctant to upgrade to K3S as he hears a couple of dozen birdies on 6m with antenna disconnected.
>> So how has this aspect of K3 performance evolved from early K3 (his is S/N sub-100) to the K3S?
>> 73
>> David G3WGN M6O
>> Member of the 6Gs team at E6GG in September 2015 www.e6gg.com<http://www.e6gg.com><http://www.e6gg.com>
>> Work us on as many bands as you can!
>>
>>
>>
>>
>>
>>
>> --
>> View this message in context: http://elecraft.365791.n2.nabble.com/6m-birdies-and-K3S-and-or-new-synth-boards-tp7604211.html
>> Sent from the Elecraft mailing list archive at Nabble.com.
>> ______________________________________________________________
>> 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
>> Message delivered to [hidden email]
>
> ______________________________________________________________
> 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
> Message delivered to [hidden email]

______________________________________________________________
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Ken_ke2n

Re: 6m birdies and K3S and/or new synth boards

In reply to this post by Dave G3WGN M6O

My K3 with the new synth (and upgraded DSP board) has an unfortunate "birdy" on 50.276 (unfortunate because this is the JT65 calling frequency in the US). I know it is a DSP-type artifact because the pitch of the birdy changes with the IF Shift control. The IF shift control does not change the frequency of the signal, just the birdy. This phenomenon is actually useful. By shifting the center frequency to 1.35 kHz I can move the spur down to zero beat. And, like all spurs, the pitch of the spur changes a lot faster than the tuning rate of the radio. The pitch of the spur also varies with the setting of the crystal filter offset (mine is set at 200 Hz).

73
Ken

Joe Subich, W4TV-4

Re: 6m birdies and K3S and/or new synth boards

The spur also changes with bandwidth. In my K3 it happens to fall at
50.279.00 with FC=1.50, BW=2.80 in DATA_A when the rig is at 50.276.00.
When going to FC=2.20, BW=4.00 the "spur" moves to ~50.285.5 and in
USB "NORM" it falls at 50.275.71 (zero beat). Again, this is fortunate
in that the spur is equivalent to a -96 dBm signal as measured on the
P3 and would be a killer if it fell "in band".

I see additional (bothersome) spurs at 50.047.57 (-100 dBm), 50,082.72
(-116 dBm), 50.095.32 (-119 dBm), 50.102.04 (-116 dBm), 50.110.52 (-118
dBm), 50.111.65 (-120 dBm), 50.112.78 (-120 dBm), 50.150.26 (-110 dBm),
50.193.57 (-103 dBm), 50.222.56 (-119 dBm), 50.351.35 (-119 dBm),
50.390.82 (-119 dBm), 50.393.90 (-110 dBm), 50.435.85 (-119 dBm),
50.465.09 (-120 dBm), and 50.486.11 (-120 dBm) - frequencies are zero
beat in USB with DSP = norm. Measurements were made with dummy load
and PRE_1 in K3 s/n 1450 with 2x KSYN3A and KXV3B.

"Bothersome" to me is > 6 dB above the receiver noise floor under the
measurement conditions described. I have not attempted to catalog
spurs on the other bands.

73,

... Joe, W4TV

On 2015-06-25 9:14 AM, Ken_ke2n via Elecraft wrote:

> My K3 with the new synth (and upgraded DSP board) has an unfortunate "birdy"
> on 50.276 (unfortunate because this is the JT65 calling frequency in the
> US). I know it is a DSP-type artifact because the pitch of the birdy
> changes with the IF Shift control. The IF shift control does not change the
> frequency of the signal, just the birdy. This phenomenon is actually useful.
> By shifting the center frequency to 1.35 kHz I can move the spur down to
> zero beat. And, like all spurs, the pitch of the spur changes a lot faster
> than the tuning rate of the radio. The pitch of the spur also varies with
> the setting of the crystal filter offset (mine is set at 200 Hz).
>
>
>
> -----
> 73
> Ken
>
> --
> View this message in context: http://elecraft.365791.n2.nabble.com/6m-birdies-and-K3S-and-or-new-synth-boards-tp7604211p7604287.html
> Sent from the Elecraft mailing list archive at Nabble.com.
> ______________________________________________________________
> 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
> Message delivered to [hidden email]
>

Dave G3WGN M6O

Re: 6m birdies and K3S and/or new synth boards

Thanks Joe for a very helpful note. This will materially aid my 'birdie hunting' when I upgrade S/N 4474 with new synths and internal preamp in a couple of weeks time.
73 Dave G3WGN M6O WJ6O

Earl

Re: 6m birdies and K3S and/or new synth boards

In reply to this post by Dave G3WGN M6O

Maybe as Elecraft suggests it is poor shielding. I am finding a birdie on 50.293, the WSPR frequency- what a shame.

I will experiment with adding the metal plate back on my new synth board. Also I will build new jumpers with some high quality cable from a decommissioned microwave I have here at the tv station.

I will update my findings...