Elecraft

KX3 BC Breakthrough

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Paul Barlow-2

KX3 BC Breakthrough

After being QRT for a number of years I'm returning to the air with a new
call and location. I am seriously considering buying a KX3 (I have a K2 and
a K1), but I'm a little concerned by reports of AM breakthrough (or whatever
the right word is). I know this is because of the direct conversion
architecture of the rig. I also understand that the IK can be shifted to
8KHz, which should solve the problem, but in doing so makes the narrower
roofing filters and dual watch inoperable.

How many owners are having problems with AM BC breakthrough. I guess it's
mainly an EU problem. I'm located in Dublin, EI.

73,

Paul EI5KI (and M0CDP)

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LA8OKA

Vedr: KX3 BC Breakthrough

I have breakthrough on my KX3.
It is most notably on 40 m.
I wouldn't Call it a problem, but it is annoying.

Martin Storli
LA8OKA
Oslo, Norway

ARCTICPEAK's Radio pages!
http://www.arcticpeak.com/radio.htm

________________________________
Fra: Paul Barlow <[hidden email]>
Til: [hidden email]
Sendt: Torsdag, 15. august 2013 12.52
Emne: [Elecraft] KX3 BC Breakthrough

After being QRT for a number of years I'm returning to the air with a new
call and location. I am seriously considering buying a KX3 (I have a K2 and
a K1), but I'm a little concerned by reports of AM breakthrough (or whatever
the right word is). I know this is because of the direct conversion
architecture of the rig. I also understand that the IK can be shifted to
8KHz, which should solve the problem, but in doing so makes the narrower
roofing filters and dual watch inoperable.

How many owners are having problems with AM BC breakthrough. I guess it's
mainly an EU problem. I'm located in Dublin, EI.

73,

Paul EI5KI (and M0CDP)

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Uwe Hermanns

Re: Vedr: KX3 BC Breakthrough

...I have AM-Breakthrough mostly in the afternoon on 20 and 15m...

73 de Uwe, DL4AC

2013/8/15 Martin Storli - LA8OKA <[hidden email]>

> I have breakthrough on my KX3.
> It is most notably on 40 m.
> I wouldn't Call it a problem, but it is annoying.
>
> Martin Storli
> LA8OKA
> Oslo, Norway
>
> ARCTICPEAK's Radio pages!
> http://www.arcticpeak.com/radio.htm
>
>
> ________________________________
> Fra: Paul Barlow <[hidden email]>
> Til: [hidden email]
> Sendt: Torsdag, 15. august 2013 12.52
> Emne: [Elecraft] KX3 BC Breakthrough
>
>
> After being QRT for a number of years I'm returning to the air with a new
> call and location. I am seriously considering buying a KX3 (I have a K2 and
> a K1), but I'm a little concerned by reports of AM breakthrough (or
> whatever
> the right word is). I know this is because of the direct conversion
> architecture of the rig. I also understand that the IK can be shifted to
> 8KHz, which should solve the problem, but in doing so makes the narrower
> roofing filters and dual watch inoperable.
>
> How many owners are having problems with AM BC breakthrough. I guess it's
> mainly an EU problem. I'm located in Dublin, EI.
>
> 73,
>
> Paul EI5KI (and M0CDP)
>
>
> ______________________________________________________________
> 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
>

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wayne burdick

Re: KX3 BC Breakthrough

Administrator

In reply to this post by Paul Barlow-2

Hi Paul,

The vast majority of KX3 users don't have any issues with strong AM broadcast stations. However, for those who do, we provide RX SHFT settings as well as control over preamp gain. These are the same signal-management strategies used by other companies using this receiver architecture. Typically, dropping preamp gain from 20 dB to 10 dB will do the trick, or you can use the 8-kHz shift setting. In either case, you only need to do this on affected bands.

Shifting the I.F. does bypass the roofing filter module, if applicable. However, this only changes the close-in dynamic range of the receiver by 8-10 dB, which still leaves the KX3 in the top 10 of all radios tested by Sherwood, etc. I still hope to provide a smaller shift that allows the use of FL2 (1500 Hz roofing filter) in narrowband operating modes.

The K3 uses a different architecture (superhet), which is inherently immune to narrowband AM IP2. But the KX3's primary application is as an ultraportable field radio, and we elected to keep it small and lightweight by using a quadrature-DC architecture.

73,
Wayne
N6KR

On Aug 15, 2013, at 3:52 AM, "Paul Barlow" <[hidden email]> wrote:

> After being QRT for a number of years I'm returning to the air with a new
> call and location. I am seriously considering buying a KX3 (I have a K2 and
> a K1), but I'm a little concerned by reports of AM breakthrough (or whatever
> the right word is). I know this is because of the direct conversion
> architecture of the rig. I also understand that the IK can be shifted to
> 8KHz, which should solve the problem, but in doing so makes the narrower
> roofing filters and dual watch inoperable….
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Help: http://mailman.qth.net/mmfaq.htm
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Igor Sokolov-2

Re: KX3 BC Breakthrough

In reply to this post by Paul Barlow-2

Paul,
I have this direct AM detection on my KX3 every day mainly on 20-15-10 m
bands/ I would not call it a problem because shifting IF 8 kHz solves it
100%. Although this disables dual RX but one seldom (if ever) needs it on
this portable QRP transceiver.
Yet the radio is the best available choice for traveling and it has got very
good receiver.

73, Igor UA9CDC
----- Original Message -----
From: "Paul Barlow" <[hidden email]>
To: <[hidden email]>
Sent: Thursday, August 15, 2013 4:52 PM
Subject: [Elecraft] KX3 BC Breakthrough

> After being QRT for a number of years I'm returning to the air with a new
> call and location. I am seriously considering buying a KX3 (I have a K2
> and
> a K1), but I'm a little concerned by reports of AM breakthrough (or
> whatever
> the right word is). I know this is because of the direct conversion
> architecture of the rig. I also understand that the IK can be shifted to
> 8KHz, which should solve the problem, but in doing so makes the narrower
> roofing filters and dual watch inoperable.
>
> How many owners are having problems with AM BC breakthrough. I guess it's
> mainly an EU problem. I'm located in Dublin, EI.
>
> 73,
>
> Paul EI5KI (and M0CDP)
>
>
> ______________________________________________________________
> 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

Igor Sokolov-2

Re: KX3 BC Breakthrough

Ron,
Switching preamp off does not help here. Shifting IF is the ultimate cure.
Besides I need preamp on on 10-15 meters most of the time to pull out weak
signals. Sometimes I need it even on 20 m.

73, Igor, UA9CDC
----- Original Message -----
From: "Ron D'Eau Claire" <[hidden email]>
To: <[hidden email]>
Sent: Friday, August 16, 2013 2:36 AM
Subject: Re: [Elecraft] KX3 BC Breakthrough

> If turning the Preamp off fixes the problem, that would be my first choice
> as long as I can hear the noise level drop when I disconnect the antenna.
>
> If removing the antenna doesn't cause the noise level to drop, then the
> preamp is likely useful for hearing weaker signals. In a QSO I'd still
> turn
> the preamp off to see if it affects my ability to hear the other station.
>
> Putting too much gain at the antenna input compromises the performance of
> any receiver
>
> 73 Ron AC7AC
>
> -----Original Message-----
> From: [hidden email]
> [mailto:[hidden email]] On Behalf Of Igor Sokolov
> Sent: Thursday, August 15, 2013 1:19 PM
> To: Paul Barlow; [hidden email]
> Subject: Re: [Elecraft] KX3 BC Breakthrough
>
> Paul,
> I have this direct AM detection on my KX3 every day mainly on 20-15-10 m
> bands/ I would not call it a problem because shifting IF 8 kHz solves it
> 100%. Although this disables dual RX but one seldom (if ever) needs it on
> this portable QRP transceiver.
> Yet the radio is the best available choice for traveling and it has got
> very
> good receiver.
>
> 73, Igor UA9CDC
>
>
> ______________________________________________________________
> 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