Elecraft

KSYN3A

Classic

List

Threaded

18 messages Options

Mike Reublin NF4L

KSYN3A

What could I expect to actually hear differently (not lab measurements) after the installation of the new synths? I have no interest in freqs below 1.8MHz, I'm not a high-speed CW guy. I chase DX (SSB, CW, RTTY) and do a bit of contesting to that end.

73, Mike NF4L
______________________________________________________________
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]

David Bunte

Re: KSYN3A

Mike -

Like you, I don't plan to go to the lower freqs., and seldom go faster than
32 wpm, but I got my board in the first shipment, and to me, my K3 "seems"
quieter on receive. That could be because I want it to be improved, but
that is clearly this impression I have.

Dave - K9FN
On May 3, 2015 2:04 PM, "Mike Reublin NF4L" <[hidden email]> wrote:

> What could I expect to actually hear differently (not lab measurements)
> after the installation of the new synths? I have no interest in freqs below
> 1.8MHz, I'm not a high-speed CW guy. I chase DX (SSB, CW, RTTY) and do a
> bit of contesting to that end.
>
> 73, Mike NF4L
> ______________________________________________________________
> 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]

Mike K2MK

Re: KSYN3A

In reply to this post by Mike Reublin NF4L

Hi Mike,

I have pondered the exact same thing. I hope folks answer you via the reflector as I, and perhaps others, would like to read the replies.

73,
Mike K2MK

<quote author="Mike Reublin NF4L">
What could I expect to actually hear differently (not lab measurements) after the installation of the new synths? I have no interest in freqs below 1.8MHz, I'm not a high-speed CW guy. I chase DX (SSB, CW, RTTY) and do a bit of contesting to that end.

73, Mike NF4L

Cady, Fred

Re: KSYN3A

In reply to this post by Mike Reublin NF4L

Hi all,
I'm working on some before and after testing to try to get a handle on what we might hear with the new synthesizer. I hope to have that done in a couple of days. I'll put a link up on my website and post the information here.
73 and cheers,
Fred KE7X

Author of:
"The Elecraft K3: Design, Configuration and Operation 2nd ed"
"The Elecraft KX3 - Going for the summit"
"The Elecraft KPA500 and KAT500 - the K-Line Dream Station"
Printed, coil bound copies of these are all available at www.elecraft.com
KPA500 and KAT500 Quick Set Up Guide
http://www.ke7x.com/home/k-line-introduction-and-set-up-guide
KAT500 and KXPA500 Tuner Operation
http://www.ke7x.com/home/kat500-and-kxpa100-tuners

> -----Original Message-----
> From: Elecraft [mailto:[hidden email]] On Behalf Of
> Mike Reublin NF4L
> Sent: Sunday, May 03, 2015 12:04 PM
> To: Elecraft List
> Subject: [Elecraft] KSYN3A
>
> What could I expect to actually hear differently (not lab measurements)
> after the installation of the new synths? I have no interest in freqs
> below 1.8MHz, I'm not a high-speed CW guy. I chase DX (SSB, CW, RTTY)
> and do a bit of contesting to that end.
>
> 73, Mike NF4L
> ______________________________________________________________
> 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]

Mike Reublin NF4L

Re: KSYN3A

In reply to this post by David Bunte

That would be nice, Dave. i'm one of the screwballs who considered the K3 noisy.

73, Mike NF4L

> On May 3, 2015, at 2:58 PM, David Bunte <[hidden email]> wrote:
>
> Mike -
>
> Like you, I don't plan to go to the lower freqs., and seldom go faster than 32 wpm, but I got my board in the first shipment, and to me, my K3 "seems" quieter on receive. That could be because I want it to be improved, but that is clearly this impression I have.
>
> Dave - K9FN
>
> On May 3, 2015 2:04 PM, "Mike Reublin NF4L" <[hidden email] <mailto:[hidden email]>> wrote:
> What could I expect to actually hear differently (not lab measurements) after the installation of the new synths? I have no interest in freqs below 1.8MHz, I'm not a high-speed CW guy. I chase DX (SSB, CW, RTTY) and do a bit of contesting to that end.
>
> 73, Mike NF4L
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft <http://mailman.qth.net/mailman/listinfo/elecraft>
> Help: http://mailman.qth.net/mmfaq.htm <http://mailman.qth.net/mmfaq.htm>
> Post: mailto:[hidden email] <mailto:[hidden email]>
>
> This list hosted by: http://www.qsl.net <http://www.qsl.net/>
> Please help support this email list: http://www.qsl.net/donate.html <http://www.qsl.net/donate.html>
> Message delivered to [hidden email] <mailto:[hidden email]>

Mike Reublin NF4L

Re: KSYN3A

In reply to this post by Cady, Fred

Thanks, Fred. I'm looking forward to seeing your results.

73, Mike NF4L

> On May 3, 2015, at 5:23 PM, Cady, Fred <[hidden email]> wrote:
>
> Hi all,
> I'm working on some before and after testing to try to get a handle on what we might hear with the new synthesizer. I hope to have that done in a couple of days. I'll put a link up on my website and post the information here.
> 73 and cheers,
> Fred KE7X
>
> Author of:
> "The Elecraft K3: Design, Configuration and Operation 2nd ed"
> "The Elecraft KX3 - Going for the summit"
> "The Elecraft KPA500 and KAT500 - the K-Line Dream Station"
> Printed, coil bound copies of these are all available at www.elecraft.com
> KPA500 and KAT500 Quick Set Up Guide
> http://www.ke7x.com/home/k-line-introduction-and-set-up-guide
> KAT500 and KXPA500 Tuner Operation
> http://www.ke7x.com/home/kat500-and-kxpa100-tuners
>
>> -----Original Message-----
>> From: Elecraft [mailto:[hidden email]] On Behalf Of
>> Mike Reublin NF4L
>> Sent: Sunday, May 03, 2015 12:04 PM
>> To: Elecraft List
>> Subject: [Elecraft] KSYN3A
>>
>> What could I expect to actually hear differently (not lab measurements)
>> after the installation of the new synths? I have no interest in freqs
>> below 1.8MHz, I'm not a high-speed CW guy. I chase DX (SSB, CW, RTTY)
>> and do a bit of contesting to that end.
>>
>> 73, Mike NF4L
>> ______________________________________________________________
>> 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]

Arie Kleingeld PA3A-2

Re: KSYN3A

In reply to this post by Mike Reublin NF4L

I installed two new SYN3A's yesterday in K3 #1255

A very positive surprise: The diversity mode has improved a lot. The
'woosh' during tuning has competely gone! Super.
A negative surprise: Tuning noise on 40m (S3 !) plus birdies.
I will install the tuning noise reduction mod (of 2009) now and see
whether that helps and i'll move the TMP cables around to improve on the
birdie problem.

73
Arie PA3A

Mike Reublin NF4L schreef op 3-5-2015 om 20:03:
> What could I expect to actually hear differently (not lab measurements) after the installation of the new synths? I have no interest in freqs below 1.8MHz, I'm not a high-speed CW guy. I chase DX (SSB, CW, RTTY) and do a bit of contesting to that end.
>
>

______________________________________________________________
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]

Johnny Siu

KSYN3A

Hello Arie,
I would suggest you install all the hardware modification as mentioned by Elecraft
http://www.elecraft.com/K3/k3_app_notes.htm
It is not difficult and many parts could be found in the junk box. I did it all for my K3 at similar serial no. range.
73
Johnny VR2XMC
寄件人︰ Arie Kleingeld PA3A <[hidden email]>
收件人︰ Mike Reublin NF4L <[hidden email]>; "[hidden email]" <[hidden email]>
傳送日期︰ 2015年05月4日 (週一) 7:14 PM
主題︰ Re: [Elecraft] KSYN3A

I installed two new SYN3A's yesterday in K3 #1255

A very positive surprise: The diversity mode has improved a lot. The
'woosh' during tuning has competely gone! Super.
A negative surprise: Tuning noise on 40m (S3 !) plus birdies.
I will install the tuning noise reduction mod (of 2009) now and see
whether that helps and i'll move the TMP cables around to improve on the
birdie problem.

73
Arie PA3A

Mike Reublin NF4L schreef op 3-5-2015 om 20:03:
> What could I expect to actually hear differently (not lab measurements) after the installation of the new synths? I have no interest in freqs below 1.8MHz, I'm not a high-speed CW guy. I chase DX (SSB, CW, RTTY) and do a bit of contesting to that end.
>
>

______________________________________________________________
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]

Mike Reublin NF4L

Re: KSYN3A

In reply to this post by Arie Kleingeld PA3A-2

Thanks, Arie.

I've never tried diversity reception. I must get around to it soon. The birdies are a worrisome report.

73, Mike NF4L

> On May 4, 2015, at 7:14 AM, Arie Kleingeld PA3A <[hidden email]> wrote:
>
> I installed two new SYN3A's yesterday in K3 #1255
>
> A very positive surprise: The diversity mode has improved a lot. The 'woosh' during tuning has competely gone! Super.
> A negative surprise: Tuning noise on 40m (S3 !) plus birdies.
> I will install the tuning noise reduction mod (of 2009) now and see whether that helps and i'll move the TMP cables around to improve on the birdie problem.
>
> 73
> Arie PA3A
>
> Mike Reublin NF4L schreef op 3-5-2015 om 20:03:
>> What could I expect to actually hear differently (not lab measurements) after the installation of the new synths? I have no interest in freqs below 1.8MHz, I'm not a high-speed CW guy. I chase DX (SSB, CW, RTTY) and do a bit of contesting to that end.
>>
>>
>

Arie Kleingeld PA3A-2

KSYN3A tuning noise on 40m

In reply to this post by Arie Kleingeld PA3A-2

Hi all,

I just installed two new KSYN3A's in K3 #1255. I found high tuning noise
on 40m.

First case:
On 40m S-3 tuning noise in the MAIN RX while tuning the MAIN RX

To reproduce:
mode: SSB, normal bandwidth
freq: 7000 -7200
no antenna connected
pre-amp off
att off
full RF gain
AGC-S
VFO tuning noise reduction Mod has no effect.

Second case, with SUB RX on:
Listening on MAIN RX
Same tuning noise audible on MAIN RX while tuning the SUB RX

Third case, with SUB RX on:
Listening on SUB RX
SUB RX has no tuning noise, neither tuning the SUB RX nor tuning the MAIN RX

(I switched the two SYNT3A's, main to sub, sub to main: NO difference)

Can anyone confirm this, or is #1255 unique in this?

73
Arie PA3A

______________________________________________________________
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]

dmb@lightstream.net

Re: KSYN3A tuning noise on 40m

Hi Arie,

Just another data-point: I tried all three of your tests, and the S-meter
stayed at S1 with no tuning noise at all on VFO-A or B.

K3 SN: 5855 w/ 2 KSYN3A's

73, Dale
WA8SRA

Johnny Siu

KSYN3A tuning noise on 40m

In reply to this post by Arie Kleingeld PA3A-2

Hello Arie,
I tried your settings in my K3 #11xx and do not have any tuning noise issues. I am afraid I cannot provide you with further assistance in this area.
In case, you find out the answer, please do share with the group. These are ancient K3 users like me in this email listing.
73
Johnny VR2XMC
寄件人︰ Arie Kleingeld PA3A <[hidden email]>
收件人︰ [hidden email]
傳送日期︰ 2015年05月4日 (週一) 9:31 PM
主題︰ [Elecraft] KSYN3A tuning noise on 40m

Hi all,

I just installed two new KSYN3A's in K3 #1255. I found high tuning noise
on 40m.

First case:
On 40m S-3 tuning noise in the MAIN RX while tuning the MAIN RX

To reproduce:
mode: SSB, normal bandwidth
freq: 7000 -7200
no antenna connected
pre-amp off
att off
full RF gain
AGC-S
VFO tuning noise reduction Mod has no effect.

Second case, with SUB RX on:
Listening on MAIN RX
Same tuning noise audible on MAIN RX while tuning the SUB RX

Third case, with SUB RX on:
Listening on SUB RX
SUB RX has no tuning noise, neither tuning the SUB RX nor tuning the MAIN RX

(I switched the two SYNT3A's, main to sub, sub to main: NO difference)

Can anyone confirm this, or is #1255 unique in this?

73
Arie PA3A

______________________________________________________________
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]

Joe Subich, W4TV-4

Re: KSYN3A tuning noise on 40m

In reply to this post by Arie Kleingeld PA3A-2

> Can anyone confirm this, or is #1255 unique in this?

I don't see it with #1450 ... I do hear a few fast tuning birdies
(350 Hz/10 Hz VFO change) but most of them are less than -120 to
-125 dBm equivalent (indicated on the calibrated P3) and are below
the noise level with an antenna connected.

73,

... Joe, W4TV

On 2015-05-04 9:31 AM, Arie Kleingeld PA3A wrote:

> Hi all,
>
> I just installed two new KSYN3A's in K3 #1255. I found high tuning noise
> on 40m.
>
> First case:
> On 40m S-3 tuning noise in the MAIN RX while tuning the MAIN RX
>
> To reproduce:
> mode: SSB, normal bandwidth
> freq: 7000 -7200
> no antenna connected
> pre-amp off
> att off
> full RF gain
> AGC-S
> VFO tuning noise reduction Mod has no effect.
>
>
> Second case, with SUB RX on:
> Listening on MAIN RX
> Same tuning noise audible on MAIN RX while tuning the SUB RX
>
>
> Third case, with SUB RX on:
> Listening on SUB RX
> SUB RX has no tuning noise, neither tuning the SUB RX nor tuning the
> MAIN RX
>
> (I switched the two SYNT3A's, main to sub, sub to main: NO difference)
>
>
> Can anyone confirm this, or is #1255 unique in this?
>
> 73
> Arie PA3A
>
> ______________________________________________________________
> 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]
>

Guy Olinger K2AV

Re: KSYN3A tuning noise on 40m

In reply to this post by Arie Kleingeld PA3A-2

As has been stated here before, operating a K3 rx with the input
unterminated is an invalid test. The rx will never be used this way to
routinely listen to "nothing connected".

Terminate the antenna connector with 50 ohms to make any test of this sort.
Also remember that 40m band noise anywhere covers up a lot of rx internal
noise. Terminated noise readings as a possible impact on received signals
start to make sense on 10m and above.

73 Guy

On Monday, May 4, 2015, Arie Kleingeld PA3A <[hidden email]> wrote:

> Hi all,
>
> I just installed two new KSYN3A's in K3 #1255. I found high tuning noise
> on 40m.
>
> First case:
> On 40m S-3 tuning noise in the MAIN RX while tuning the MAIN RX
>
> To reproduce:
> mode: SSB, normal bandwidth
> freq: 7000 -7200
> no antenna connected
> pre-amp off
> att off
> full RF gain
> AGC-S
> VFO tuning noise reduction Mod has no effect.
>
>
> Second case, with SUB RX on:
> Listening on MAIN RX
> Same tuning noise audible on MAIN RX while tuning the SUB RX
>
>
> Third case, with SUB RX on:
> Listening on SUB RX
> SUB RX has no tuning noise, neither tuning the SUB RX nor tuning the MAIN
> RX
>
> (I switched the two SYNT3A's, main to sub, sub to main: NO difference)
>
>
> Can anyone confirm this, or is #1255 unique in this?
>
> 73
> Arie PA3A
>
> ______________________________________________________________
> 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]
>

--
Sent via Gmail Mobile on my iPhone
______________________________________________________________
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]

Arie Kleingeld PA3A-2

Re: KSYN3A tuning noise on 40m

Hey Guy,

thanks for your remark on the termination of the K3.

To give you a rough idea of the relative tuning noise, measured with the
K3 dBV meter:
- 4 dB above noise floor (terminated 50 ohm)
- 5 dB above noise floor (open antenna input)
(values + or - 0.5 dB)

On 10m, the tuning noise adds about 2dB to the noise floor (terminated
measurement)

About the conditions on 40m: well aware of that and the effect on
hearing tuning noise, :-) (...after nearly 40 years on HF. At least s7
noise on 40m where I live now.)

The tuning noise on 40m just struck me. I did not expect to hear it that
loud on the K3. I never noticed this with the old KSYN's so that is why
I'm asking around in the reflector.
I would not have heard it if I did not have to do the calibrations after
installing the KSYN3A's.

BTW: I never measured it on my K2 or FT1000MP (both are no longer in my
possession so I cannot check that)

73
Arie PA3A

Guy Olinger K2AV schreef op 4-5-2015 om 16:59:

> As has been stated here before, operating a K3 rx with the input
> unterminated is an invalid test. The rx will never be used this way to
> routinely listen to "nothing connected".
>
> Terminate the antenna connector with 50 ohms to make any test of this
> sort. Also remember that 40m band noise anywhere covers up a lot of rx
> internal noise. Terminated noise readings as a possible impact on
> received signals start to make sense on 10m and above.
>
> 73 Guy

N2TK

Re: KSYN3A tuning noise on 40m

In reply to this post by Arie Kleingeld PA3A-2

I can't duplicate on #311 and #1435.
Time to call Elecraft.
73,
N2TK, Tony

-----Original Message-----
From: Elecraft [mailto:[hidden email]] On Behalf Of Arie
Kleingeld PA3A
Sent: Monday, May 04, 2015 9:32 AM
To: [hidden email]
Subject: [Elecraft] KSYN3A tuning noise on 40m

Hi all,

I just installed two new KSYN3A's in K3 #1255. I found high tuning noise on
40m.

First case:
On 40m S-3 tuning noise in the MAIN RX while tuning the MAIN RX

To reproduce:
mode: SSB, normal bandwidth
freq: 7000 -7200
no antenna connected
pre-amp off
att off
full RF gain
AGC-S
VFO tuning noise reduction Mod has no effect.

Second case, with SUB RX on:
Listening on MAIN RX
Same tuning noise audible on MAIN RX while tuning the SUB RX

Third case, with SUB RX on:
Listening on SUB RX
SUB RX has no tuning noise, neither tuning the SUB RX nor tuning the MAIN RX

(I switched the two SYNT3A's, main to sub, sub to main: NO difference)

Can anyone confirm this, or is #1255 unique in this?

73
Arie PA3A

______________________________________________________________
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]

Richard Ferch

Re: KSYN3A tuning noise on 40m

In reply to this post by Arie Kleingeld PA3A-2

My experience has been that the tuning noise is strongly affected by the
positioning of the TMP cables, regardless of whether you have the old
KSYN3's or the new KSYN3A's.

I had heard some slight tuning noise on higher bands with the old
KSYN3's, but only with no antenna connected, which is not a realistic
test. After I put the new KSYN3A's in, at first I had much higher tuning
noise (a buzz or rapid clicks when turning the tuning knob), but I
opened up the rig and repositioned the TMP cables and since then the
tuning noise has completely disappeared, even with no antenna connected.

I do not have the VFO tuning noise reduction mod installed.

As for the rapidly tuning birdies (the ones that can be eliminated with
the CONFIG:SIG RMV option), I have not done a careful check. However,
while they may appear at different places than they did before (perhaps
that might be related to a reference oscillator adjustment), they do not
seem to me to be any worse than they were with the old synth boards.

73,
Rich VE3KI
K3 #1595
______________________________________________________________
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]

wayne burdick

Re: KSYN3A tuning noise on 40m

Administrator

The K3 has very high dynamic range, requiring a high-level local oscillator (the synth). One way to minimize spurs ("birdies") in a superhet design of this type is to include very narrow-band filtering, which we used throughout the radio. The ham-band filters are all just a bit wider than the ham bands themselves, there are multiple I.F. rejection traps, and there's a very narrow triple-tuned filter on the noise blanker.

The other way to minimize spurs is to enclose every subassembly in its own shield and connect them when coax cables. While we use shielding where absolutely necessary, we tried to avoid extensive shielding because it would have dramatically increased the size, weight, and cost of the K3. Instead, we used careful PCB layout, just the right number of coax cables, and balanced low-pass filtering in the first mixer that rolls off the VHF and UHF synth harmonics. The combination of these techniques results in very few spurs within ham bands.

Those spurs which persist are generally very low level, inaudible with any kind of antenna connected. For any "fast-tuning" (VFO harmonic-related) spurs that remain above the noise floor, we provided the CONFIG:SIG RMV menu entry -- a variation on spur-mapping that can be quite effective.

It's not surprising that certain very low-level spurs would change in level with repositioning of the coax cables, since they typically arise from UHF harmonics of the VFO.

73,
Wayne
N6KR

On May 4, 2015, at 2:17 PM, Richard Ferch <[hidden email]> wrote:

> My experience has been that the tuning noise is strongly affected by the positioning of the TMP cables, regardless of whether you have the old KSYN3's or the new KSYN3A's.
>
> I had heard some slight tuning noise on higher bands with the old KSYN3's, but only with no antenna connected, which is not a realistic test. After I put the new KSYN3A's in, at first I had much higher tuning noise (a buzz or rapid clicks when turning the tuning knob), but I opened up the rig and repositioned the TMP cables and since then the tuning noise has completely disappeared, even with no antenna connected.
>
> I do not have the VFO tuning noise reduction mod installed.
>
> As for the rapidly tuning birdies (the ones that can be eliminated with the CONFIG:SIG RMV option), I have not done a careful check. However, while they may appear at different places than they did before (perhaps that might be related to a reference oscillator adjustment), they do not seem to me to be any worse than they were with the old synth boards.
>
> 73,
> Rich VE3KI
> K3 #1595
> ______________________________________________________________
> 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]