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KX3 direct conversion system

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須崎純一

KX3 direct conversion system

Hi all,
I built KX3 kit (S/N830) up last week after fixing some errors.
As soon as trying some functions, I found it's really a direct
conversion system. A weak leaked signal was observed with another
receiver just on the watching frequency.
In my boyhood, I built Mizuho DC-701 which was a copy model of Heathkit
HW-7. DC-701 also adopted direct conversion system and my local
station could detect my receiving point. The leaked signal from KX3 is
not so strong as that of DC-701 and almost no problem.
Direct conversion with DSP system will be possibly adopted in higher
class transceiver.
DC on 2m is interesting, however, challenging.
So transverter is reasonable solution and I'm expecting the module again.
Many thanks for proposing the innovated equipment.

The block diagram shows the transmission system is also 'direct conversion'.
The local oscillating frequency seems to be basically equal to the
transmission frequency.
Is it correct?

Just one more twitting. The optional microphone looks something a
little cheap, because it's same as that of Chinese kit KN7Qa.

Jun, JI1TLL

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Matt Maguire

Re: KX3 direct conversion system

If the leakage is troublesome, you can try enabling the isolation amplifier (menu setting RX ISO)

73, Matt VK2ACL.

On 16/08/2012, at 1:02 AM, 須崎純一 <[hidden email]> wrote:

>
> Hi all,
> I built KX3 kit (S/N830) up last week after fixing some errors.
> As soon as trying some functions, I found it's really a direct
> conversion system. A weak leaked signal was observed with another
> receiver just on the watching frequency.
> In my boyhood, I built Mizuho DC-701 which was a copy model of Heathkit
> HW-7. DC-701 also adopted direct conversion system and my local
> station could detect my receiving point. The leaked signal from KX3 is
> not so strong as that of DC-701 and almost no problem.
> Direct conversion with DSP system will be possibly adopted in higher
> class transceiver.
> DC on 2m is interesting, however, challenging.
> So transverter is reasonable solution and I'm expecting the module again.
> Many thanks for proposing the innovated equipment.
>
> The block diagram shows the transmission system is also 'direct conversion'.
> The local oscillating frequency seems to be basically equal to the
> transmission frequency.
> Is it correct?
>
> Just one more twitting. The optional microphone looks something a
> little cheap, because it's same as that of Chinese kit KN7Qa.
>
> Jun, JI1TLL
>
> ______________________________________________________________
> 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

mzilmer

Re: KX3 direct conversion system

In reply to this post by 須崎純一

Hi Jun,

If you haven't tried it, set RX ISO to ON. This enables an isolation amplifier that keeps the LO greatly attenuated outside the KX3. The amp draws something like 10 mA, so use it only when you need it.

73,
Matt Zilmer, W6NIA

-----Original Message-----
From: [hidden email] [mailto:[hidden email]] On Behalf Of ?? ??
Sent: Wednesday, August 15, 2012 8:03 AM
To: [hidden email]
Subject: [Elecraft] KX3 direct conversion system

Hi all,
I built KX3 kit (S/N830) up last week after fixing some errors.
As soon as trying some functions, I found it's really a direct conversion system. A weak leaked signal was observed with another receiver just on the watching frequency.
In my boyhood, I built Mizuho DC-701 which was a copy model of Heathkit
HW-7. DC-701 also adopted direct conversion system and my local
station could detect my receiving point. The leaked signal from KX3 is
not so strong as that of DC-701 and almost no problem.
Direct conversion with DSP system will be possibly adopted in higher class transceiver.
DC on 2m is interesting, however, challenging.
So transverter is reasonable solution and I'm expecting the module again.
Many thanks for proposing the innovated equipment.

The block diagram shows the transmission system is also 'direct conversion'.
The local oscillating frequency seems to be basically equal to the transmission frequency.
Is it correct?

Just one more twitting. The optional microphone looks something a
little cheap, because it's same as that of Chinese kit KN7Qa.

Jun, JI1TLL

______________________________________________________________
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Help: http://mailman.qth.net/mmfaq.htm
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wayne burdick

Re: KX3 direct conversion system

Administrator

In reply to this post by 須崎純一

須崎純 (Jun) wrote:

> I built KX3 kit (S/N830) up last week after fixing some errors.
> As soon as trying some functions, I found it's really a direct
> conversion system. A weak leaked signal was observed with another
> receiver just on the watching frequency.

You can reduce the KX3's VFO signal leakage to another receiver nearby
by setting MENU:RX ISO to ON.

Yes, it is similar to direct conversion, except that there are two
channels (I and Q, like other SDRs), allowing for image rejection. The
KX3 uses this architecture rather than superhet to provide the SDR
feature, as well as to reduce the number of stages, allowing the unit
to be very compact.

73,
Wayne
N6KR

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Jun Susaki

Re: KX3 direct conversion system

In reply to this post by mzilmer

Hi Matt,

Thanks for your quick response.
The function is sometimes effective especially in Tokyo.
The current consumption +10mA is not ignorable in outdoor.
Thank you again for useful information.

Jun, JI1TLL

> From: [hidden email]
> To: [hidden email]; [hidden email]
> Date: Wed, 15 Aug 2012 08:49:18 -0700
> Subject: RE: [Elecraft] KX3 direct conversion system
>
> Hi Jun,
>
> If you haven't tried it, set RX ISO to ON. This enables an isolation amplifier that keeps the LO greatly attenuated outside the KX3. The amp draws something like 10 mA, so use it only when you need it.
>
> 73,
> Matt Zilmer, W6NIA
>
>
> -----Original Message-----
> From: [hidden email] [mailto:[hidden email]] On Behalf Of ?? ??
> Sent: Wednesday, August 15, 2012 8:03 AM
> To: [hidden email]
> Subject: [Elecraft] KX3 direct conversion system
>
>
> Hi all,
> I built KX3 kit (S/N830) up last week after fixing some errors.
> As soon as trying some functions, I found it's really a direct conversion system. A weak leaked signal was observed with another receiver just on the watching frequency.
> In my boyhood, I built Mizuho DC-701 which was a copy model of Heathkit
> HW-7. DC-701 also adopted direct conversion system and my local
> station could detect my receiving point. The leaked signal from KX3 is
> not so strong as that of DC-701 and almost no problem.
> Direct conversion with DSP system will be possibly adopted in higher class transceiver.
> DC on 2m is interesting, however, challenging.
> So transverter is reasonable solution and I'm expecting the module again.
> Many thanks for proposing the innovated equipment.
>
> The block diagram shows the transmission system is also 'direct conversion'.
> The local oscillating frequency seems to be basically equal to the transmission frequency.
> Is it correct?
>
> Just one more twitting. The optional microphone looks something a
> little cheap, because it's same as that of Chinese kit KN7Qa.
>
> Jun, JI1TLL
>
> ______________________________________________________________
> 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

Johnny Siu

KX3 direct conversion system

Hello Jun,

Will go to the Tokyo Ham Fair next week? I will be there next week. I could possibly wonder around the A1 club, Tokyo International Amateur Radio Association, Icom or JARL booths.

TNX & 73,

Johnny VR2XMC

________________________________
寄件人︰須崎純一 <[hidden email]>
收件人︰ [hidden email]
傳送日期︰ 2012年08月16日 (週四) 12:34 AM
主題︰ Re: [Elecraft] KX3 direct conversion system

Hi Matt,

Thanks for your quick response.
The function is sometimes effective especially in Tokyo.
The current consumption +10mA is not ignorable in outdoor.
Thank you again for useful information.

Jun, JI1TLL

> From: [hidden email]
> To: [hidden email]; [hidden email]
> Date: Wed, 15 Aug 2012 08:49:18 -0700
> Subject: RE: [Elecraft] KX3 direct conversion system
>
> Hi Jun,
>
> If you haven't tried it, set RX ISO to ON. This enables an isolation amplifier that keeps the LO greatly attenuated outside the KX3. The amp draws something like 10 mA, so use it only when you need it.
>
> 73,
> Matt Zilmer, W6NIA
>
>
> -----Original Message-----
> From: [hidden email] [mailto:[hidden email]] On Behalf Of ?? ??
> Sent: Wednesday, August 15, 2012 8:03 AM
> To: [hidden email]
> Subject: [Elecraft] KX3 direct conversion system
>
>
> Hi all,
> I built KX3 kit (S/N830) up last week after fixing some errors.
> As soon as trying some functions, I found it's really a direct conversion system. A weak leaked signal was observed with another receiver just on the watching frequency.
> In my boyhood, I built Mizuho DC-701 which was a copy model of Heathkit
> HW-7. DC-701 also adopted direct conversion system and my local
> station could detect my receiving point. The leaked signal from KX3 is
> not so strong as that of DC-701 and almost no problem.
> Direct conversion with DSP system will be possibly adopted in higher class transceiver.
> DC on 2m is interesting, however, challenging.
> So transverter is reasonable solution and I'm expecting the module again.
> Many thanks for proposing the innovated equipment.
>
> The block diagram shows the transmission system is also 'direct conversion'.
> The local oscillating frequency seems to be basically equal to the transmission frequency.
> Is it correct?
>
> Just one more twitting. The optional microphone looks something a
> little cheap, because it's same as that of Chinese kit KN7Qa.
>
> Jun, JI1TLL
>
> ______________________________________________________________
> 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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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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k6dgw

Re: KX3 direct conversion system

In reply to this post by wayne burdick

On 8/15/2012 7:46 PM, Ron D'Eau Claire wrote:
> Us OTs recognize this system as the reverse of the phasing system of
> generating SSB that was popular in the 1950's.

While I do my best to avoid the OT label, it does seem to be reality.
Tweaking the HT-32 for best carrier/sideband suppression [not always the
same points] was a chore. The adjustments also didn't last. Those
would have been "The Good Old Days."

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 2012 Cal QSO Party 6-7 Oct 2012
- www.cqp.org

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Jun Susaki

Re: KX3 direct conversion system

In reply to this post by wayne burdick

Hi Wayne,

I appreciate the announcement from Elecraft.
I tried RX ISO function, and the leaked signal was disappeared or canceled -25dB approx. on 6m measuring with my rough s-meter.
Let me know any notice other than current consumption, if you have so far and can open.
What a deep handy!

Jun, JI1TLL

> CC: [hidden email]
> From: [hidden email]
> To: [hidden email]
> Subject: Re: KX3 direct conversion system
> Date: Wed, 15 Aug 2012 09:07:08 -0700
>
> 須崎純 (Jun) wrote:
>
> > I built KX3 kit (S/N830) up last week after fixing some errors.
> > As soon as trying some functions, I found it's really a direct
> > conversion system. A weak leaked signal was observed with another
> > receiver just on the watching frequency.
>
> You can reduce the KX3's VFO signal leakage to another receiver nearby
> by setting MENU:RX ISO to ON.
>
> Yes, it is similar to direct conversion, except that there are two
> channels (I and Q, like other SDRs), allowing for image rejection. The
> KX3 uses this architecture rather than superhet to provide the SDR
> feature, as well as to reduce the number of stages, allowing the unit
> to be very compact.
>
> 73,
> Wayne
> N6KR

Jun Susaki

Re: KX3 direct conversion system

In reply to this post by Johnny Siu

Hello Johnny,

Exactly! I'll be there (Tokyo big site) on 25-26th, almost at booth J-08.
I expected to touch KX3 there last year, but regrettably no information in Japan.
At that time, I didn't forecast the 'X'mas order'.
Hope to see you there.

Jun JI1TLL

Date: Thu, 16 Aug 2012 06:52:11 +0800
From: [hidden email]
Subject: KX3 direct conversion system
To: [hidden email]
CC: [hidden email]

Hello Jun, Will go to the Tokyo Ham Fair next week? I will be there next week. I could possibly wonder around the A1 club, Tokyo International Amateur Radio Association, Icom or JARL booths. TNX & 73,

Johnny VR2XMC
寄件人︰須崎純一 <[hidden email]>
收件人︰ [hidden email]
傳送日期︰ 2012年08月16日 (週四) 12:34 AM
主題︰ Re: [Elecraft] KX3 direct conversion system

Hi Matt,

Thanks for your quick response.
The function is sometimes effective especially in Tokyo.
The current consumption +10mA is not ignorable in outdoor.
Thank you again for useful information.

Jun, JI1TLL

Many thanks for proposing the innovated equipment.

>
> The block diagram shows the transmission system is also 'direct conversion'.
> The local oscillating frequency seems to be basically equal to the transmission frequency.
> Is it correct?
>
> Just one more twitting. The optional microphone looks something a
> little cheap, because it's same as that of Chinese kit KN7Qa.
>
> Jun, JI1TLL
>
> ______________________________________________________________
> 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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by: http://www.qsl.net/
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須崎純一

Re: KX3 direct conversion system

In reply to this post by wayne burdick

Many thanks for OT's comment on this system.
I don't understand the process within the multiplexer chip in detail, however, I think it's basically PSN.
In Japan, Kenwood adopted PSN in it's first SSB transmitter TX-15 about 45 years ago.
US manufactures were more advanced at that time.
It's my pleasure Elecraft has now established it's unique position.

73, Jun JI1TLL

> From: [hidden email]
> To: [hidden email]
> Date: Wed, 15 Aug 2012 19:46:10 -0700
> Subject: Re: [Elecraft] KX3 direct conversion system
>
> Us OTs recognize this system as the reverse of the phasing system of generating SSB that was popular in the 1950's. Phasing lost popularity as low-cost and high-quality crystal filters became available because, like the KX3, they depended upon highly accurate phase shift and gain control over the entire bandwidth of the audio channel to cancel the opposite sideband. (Remember, everything then was analog, meaning building wide-band analog phase shift networks that remained stable from discrete components.) Back in the "day" it wasn't easy to do and achieve more than 20 or perhaps 30 dB of attenuation. That was adequate in the 50's when almost all 'phone' stations were using double-sideband a.m. occupying 6 kHz of bandwidth.
>
> In the KX3 it appears to be returning with substantially greater phase and gain accuracy, and so opposite sideband suppression, than we could achieve back then.
>
> 73, Ron AC7AC
>
> -----Original Message-----
> From: [hidden email] [mailto:[hidden email]] On Behalf Of Wayne Burdick
> Sent: Wednesday, August 15, 2012 9:07 AM
> To: [hidden email]
> Cc: [hidden email]
> Subject: Re: [Elecraft] KX3 direct conversion system
>
> 須崎純 (Jun) wrote:
>
> > I built KX3 kit (S/N830) up last week after fixing some errors.
> > As soon as trying some functions, I found it's really a direct
> > conversion system. A weak leaked signal was observed with another
> > receiver just on the watching frequency.
>
> You can reduce the KX3's VFO signal leakage to another receiver nearby by setting MENU:RX ISO to ON.
>
> Yes, it is similar to direct conversion, except that there are two channels (I and Q, like other SDRs), allowing for image rejection. The
> KX3 uses this architecture rather than superhet to provide the SDR feature, as well as to reduce the number of stages, allowing the unit to be very compact.
>
> 73,
> Wayne
> N6KR
>
>
> ______________________________________________________________
> 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

須崎純一

KX3 L.O. frequency below 10MHz ?

In reply to this post by 須崎純一

Dear Sir,

I have one question to complete my block diagram for the approval.
The following footnote is added to the disclosed block diagram.

"L.O. output is at the operating frequency."

The L.O. VCXO Si570, however, could cover basically over 10MHz.
Some devices might be omitted between LO and the mixer in operating lower than 10MHz.
Let me know the hidden block and the basic oscillation frequency in that case on 1.8-7 MHz.

Jun JI1TLL,

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wayne burdick

Re: KX3 L.O. frequency below 10MHz ?

Administrator

Hi Jun,

Below VFO=2.5 MHz, we divide the synth output down much further, so
the LO is always at or above 10 MHz.

We're working on a new document that should cover all JA information
requirements.

73,
Wayne
N6KR

On Sep 6, 2012, at 9:50 AM, 須崎純一 wrote:

>
> Dear Sir,
>
> I have one question to complete my block diagram for the approval.
> The following footnote is added to the disclosed block diagram.
>
> "L.O. output is at the operating frequency."
>
> The L.O. VCXO Si570, however, could cover basically over 10MHz.
> Some devices might be omitted between LO and the mixer in operating
> lower than 10MHz.
> Let me know the hidden block and the basic oscillation frequency in
> that case on 1.8-7 MHz.
>
> Jun JI1TLL,
>
>
> ______________________________________________________________
> 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

Jun Susaki

Re: KX3 L.O. frequency below 10MHz ?

Hi Wayne,

OK, L.O. output is divided into the mixer.
I'm expecting your new document.
Thank you for your rapid response.

Jun I1TLL,

> CC: [hidden email]
> From: [hidden email]
> To: [hidden email]
> Subject: Re: [Elecraft] KX3 L.O. frequency below 10MHz ?
> Date: Thu, 6 Sep 2012 10:51:03 -0700
>
> Hi Jun,
>
> Below VFO=2.5 MHz, we divide the synth output down much further, so
> the LO is always at or above 10 MHz.
>
> We're working on a new document that should cover all JA information
> requirements.
>
> 73,
> Wayne
> N6KR
>
>
> On Sep 6, 2012, at 9:50 AM, 須崎純一 wrote:
>
> >
> > Dear Sir,
> >
> > I have one question to complete my block diagram for the approval.
> > The following footnote is added to the disclosed block diagram.
> >
> > "L.O. output is at the operating frequency."
> >
> > The L.O. VCXO Si570, however, could cover basically over 10MHz.
> > Some devices might be omitted between LO and the mixer in operating
> > lower than 10MHz.
> > Let me know the hidden block and the basic oscillation frequency in
> > that case on 1.8-7 MHz.
> >
> > Jun JI1TLL,
> >
> >
> > ______________________________________________________________
> > 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
>