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Re: K3 Future Factory Hardware Updates; + New beta f/w release 3.27

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Joe Subich, W4TV-4

Re: K3 Future Factory Hardware Updates; + New beta f/w release 3.27

Eric,

> Please note that the last item, the IF Output Buffer Gain mMod,
> is slightly different than the similar N8LP mod some have been
> performing on their K3s independently. We determined that only
> one value needs to change to implement the gain increase for
> the IF output. We are changing R8 from 1K ohms to 13K ohms.

Are you saying it is not necessary to increase the current in
J309 to handle the higher signal levels?

With this change, what is the transfer gain/loss from the antenna
input to the IF output with the IF output terminated in 50 Ohms?

73,

... Joe, W4TV

> -----Original Message-----
> From: [hidden email]
> [mailto:[hidden email]] On Behalf Of Eric
> Swartz - WA6HHQ, Elecraft
> Sent: Tuesday, August 25, 2009 1:53 PM
> To: [hidden email]
> Subject: Re: [Elecraft] K3 Future Factory Hardware Updates; +
> New beta f/w release 3.27
>
>
> Hi Roy,
>
> As of today, we have made the following enhancements to all
> K3s leaving
> the factory:
>
> K3 VFO TUNING NOISE REDUCTION (requires f/w 3.25 or later)
> K3 AUTOMATIC FRONT END PROTECTION (1 wire mod)
> K3 IF OUTPUT BUFFER GAIN MOD (For the P3, LP-PAN etc) (1
> resistor value
> change)
>
> Based on feedback form those that have tried the preliminary
> release of
> these changes, we are comfortable with adding them as
> standard K3 features.
>
> Please note that the last item, the IF Output Buffer Gain mMod, is
> slightly different than the similar N8LP mod some have been
> performing
> on their K3s independently. We determined that only one value
> needs to
> change to implement the gain increase for the IF output. We
> are changing
> R8 from 1K ohms to 13K ohms. (Those that have made the N8LP mod may
> also leave it as is.)
>
> Also, we are releasing new beta f/w today, MCU 3.27/DSP 2.24. This is
> already available on the web page at:
>
> http://www.elecraft.com/K3/k3_software.htm
>
> This release includes:
>
> *ADDITIONAL NOISE REDUCTION (NR) IMPROVEMENTS.
> *AUTONOTCH depth improved.
> *SHIFT=.01 FIXED WITH LOW SIDETONE PITCH (300 Hz).
> *VFOs NOW TUNE DOWN TO 490 kHz.
>
> We never sleep in Aptos! :-)
>
> 73, Eric WA6HHQ
>
> Roy Morris wrote:
> > I would like to know if is the intention of Elecraft to incorporate
> > the K3 AUTOMATIC FRONT-END PROTECTION mod and the K3VFO
> TUNING NOISE REDUCTION mod in future PC boards. If so, I
> plan to install these mods in my K3s. Roy Morris W4WFB
> >
> ______________________________________________________________
> 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
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Alan Bloom

Re: K3 Future Factory Hardware Updates; + New beta f/w release 3.27

The resistor change increases the IF output signal by a little over 10
dB.

It's interesting to note that changing the FET source resistor does not
result in a 50-ohm output impedance because the resistor is in parallel
with the FET source resistance. A 50-ohm match is not required in any
case.

Al N1AL

On Tue, 2009-08-25 at 16:11 -0400, Joe Subich, W4TV wrote:

> Eric,
>
> > Please note that the last item, the IF Output Buffer Gain mMod,
> > is slightly different than the similar N8LP mod some have been
> > performing on their K3s independently. We determined that only
> > one value needs to change to implement the gain increase for
> > the IF output. We are changing R8 from 1K ohms to 13K ohms.
>
> Are you saying it is not necessary to increase the current in
> J309 to handle the higher signal levels?
>
> With this change, what is the transfer gain/loss from the antenna
> input to the IF output with the IF output terminated in 50 Ohms?
>
> 73,
>
> ... Joe, W4TV
>
>
>
> > -----Original Message-----
> > From: [hidden email]
> > [mailto:[hidden email]] On Behalf Of Eric
> > Swartz - WA6HHQ, Elecraft
> > Sent: Tuesday, August 25, 2009 1:53 PM
> > To: [hidden email]
> > Subject: Re: [Elecraft] K3 Future Factory Hardware Updates; +
> > New beta f/w release 3.27
> >
> >
> > Hi Roy,
> >
> > As of today, we have made the following enhancements to all
> > K3s leaving
> > the factory:
> >
> > K3 VFO TUNING NOISE REDUCTION (requires f/w 3.25 or later)
> > K3 AUTOMATIC FRONT END PROTECTION (1 wire mod)
> > K3 IF OUTPUT BUFFER GAIN MOD (For the P3, LP-PAN etc) (1
> > resistor value
> > change)
> >
> > Based on feedback form those that have tried the preliminary
> > release of
> > these changes, we are comfortable with adding them as
> > standard K3 features.
> >
> > Please note that the last item, the IF Output Buffer Gain mMod, is
> > slightly different than the similar N8LP mod some have been
> > performing
> > on their K3s independently. We determined that only one value
> > needs to
> > change to implement the gain increase for the IF output. We
> > are changing
> > R8 from 1K ohms to 13K ohms. (Those that have made the N8LP mod may
> > also leave it as is.)
> >
> > Also, we are releasing new beta f/w today, MCU 3.27/DSP 2.24. This is
> > already available on the web page at:
> >
> > http://www.elecraft.com/K3/k3_software.htm
> >
> > This release includes:
> >
> > *ADDITIONAL NOISE REDUCTION (NR) IMPROVEMENTS.
> > *AUTONOTCH depth improved.
> > *SHIFT=.01 FIXED WITH LOW SIDETONE PITCH (300 Hz).
> > *VFOs NOW TUNE DOWN TO 490 kHz.
> >
> > We never sleep in Aptos! :-)
> >
> > 73, Eric WA6HHQ
> >
> > Roy Morris wrote:
> > > I would like to know if is the intention of Elecraft to incorporate
> > > the K3 AUTOMATIC FRONT-END PROTECTION mod and the K3VFO
> > TUNING NOISE REDUCTION mod in future PC boards. If so, I
> > plan to install these mods in my K3s. Roy Morris W4WFB
> > >
> > ______________________________________________________________
> > 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

Joe Subich, W4TV-4

Re: K3 Future Factory Hardware Updates; + New beta f/w release 3.27

> A 50-ohm match is not required in any case.

Thats not exactly true. With devices like LP-Pan or
SDR-IQ that have 50 Ohm inputs connected to what is a
high impedance output, the transfer loss (antenna to
IF) was still in the range of -6dB even with the N8LP
modification. The rest of the solution was to use a
Clifton Labs Z-10000 buffer amplifier (high impedance
input) in a unity gain configuration, install a 4:1 or
9:1 (step down) transformer, or modify the SDR-IQ for
a 200 Ohm input.

73,

... Joe, W4TV

> -----Original Message-----
> From: Alan Bloom [mailto:[hidden email]]
> Sent: Tuesday, August 25, 2009 4:17 PM
> To: [hidden email]
> Cc: 'Eric Swartz - WA6HHQ, Elecraft'; [hidden email]
> Subject: Re: [Elecraft] K3 Future Factory Hardware Updates; +
> New beta f/w release 3.27
>
>
> The resistor change increases the IF output signal by a
> little over 10 dB.
>
> It's interesting to note that changing the FET source
> resistor does not result in a 50-ohm output impedance because
> the resistor is in parallel with the FET source resistance.
> A 50-ohm match is not required in any case.
>
> Al N1AL
>
>
> On Tue, 2009-08-25 at 16:11 -0400, Joe Subich, W4TV wrote:
> > Eric,
> >
> > > Please note that the last item, the IF Output Buffer Gain mMod,
> > > is slightly different than the similar N8LP mod some have been
> > > performing on their K3s independently. We determined that only
> > > one value needs to change to implement the gain increase for
> > > the IF output. We are changing R8 from 1K ohms to 13K ohms.
> >
> > Are you saying it is not necessary to increase the current in
> > J309 to handle the higher signal levels?
> >
> > With this change, what is the transfer gain/loss from the antenna
> > input to the IF output with the IF output terminated in 50 Ohms?
> >
> > 73,
> >
> > ... Joe, W4TV
> >
> >
> >
> > > -----Original Message-----
> > > From: [hidden email]
> > > [mailto:[hidden email]] On Behalf Of Eric
> > > Swartz - WA6HHQ, Elecraft
> > > Sent: Tuesday, August 25, 2009 1:53 PM
> > > To: [hidden email]
> > > Subject: Re: [Elecraft] K3 Future Factory Hardware Updates; +
> > > New beta f/w release 3.27
> > >
> > >
> > > Hi Roy,
> > >
> > > As of today, we have made the following enhancements to all
> > > K3s leaving
> > > the factory:
> > >
> > > K3 VFO TUNING NOISE REDUCTION (requires f/w 3.25 or later) K3
> > > AUTOMATIC FRONT END PROTECTION (1 wire mod) K3 IF OUTPUT BUFFER
> > > GAIN MOD (For the P3, LP-PAN etc) (1 resistor value
> > > change)
> > >
> > > Based on feedback form those that have tried the preliminary
> > > release of
> > > these changes, we are comfortable with adding them as
> > > standard K3 features.
> > >
> > > Please note that the last item, the IF Output Buffer Gain mMod, is
> > > slightly different than the similar N8LP mod some have been
> > > performing
> > > on their K3s independently. We determined that only one value
> > > needs to
> > > change to implement the gain increase for the IF output. We
> > > are changing
> > > R8 from 1K ohms to 13K ohms. (Those that have made the
> N8LP mod may
> > > also leave it as is.)
> > >
> > > Also, we are releasing new beta f/w today, MCU 3.27/DSP
> 2.24. This
> > > is
> > > already available on the web page at:
> > >
> > > http://www.elecraft.com/K3/k3_software.htm
> > >
> > > This release includes:
> > >
> > > *ADDITIONAL NOISE REDUCTION (NR) IMPROVEMENTS.
> > > *AUTONOTCH depth improved.
> > > *SHIFT=.01 FIXED WITH LOW SIDETONE PITCH (300 Hz).
> > > *VFOs NOW TUNE DOWN TO 490 kHz.
> > >
> > > We never sleep in Aptos! :-)
> > >
> > > 73, Eric WA6HHQ
> > >
> > > Roy Morris wrote:
> > > > I would like to know if is the intention of Elecraft to
> > > > incorporate
> > > > the K3 AUTOMATIC FRONT-END PROTECTION mod and the K3VFO
> > > TUNING NOISE REDUCTION mod in future PC boards. If so, I
> > > plan to install these mods in my K3s. Roy Morris W4WFB
> > > >
> > > ______________________________________________________________
> > > 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
>

Don Wilhelm-4

Re: K3 Future Factory Hardware Updates; + New beta f/w release 3.27

Joe,

Are you making an assumption that the P3 input impedance is 50 ohms?
That may or may not be true. I don't know the design parameters of the
P3, but it certainly occurs to me that it is not necessary to use a 50
ohm input impedance.

Yes, SDR-IQ and LP-PAN have the 50 ohm input, so connecting those
devices to the K3 IF Out would cause loss.

73,
Don W3FPR

Joe Subich, W4TV wrote:

>
>> A 50-ohm match is not required in any case.
>>
>
> That’s not exactly true. With devices like LP-Pan or
> SDR-IQ that have 50 Ohm inputs connected to what is a
> high impedance output, the transfer loss (antenna to
> IF) was still in the range of -6dB even with the N8LP
> modification. The rest of the solution was to use a
> Clifton Labs Z-10000 buffer amplifier (high impedance
> input) in a unity gain configuration, install a 4:1 or
> 9:1 (step down) transformer, or modify the SDR-IQ for
> a 200 Ohm input.
>
> 73,
>
> ... Joe, W4TV
>
>

N8LP

Re: K3 Future Factory Hardware Updates; + New beta f/w release 3.27

SPICE modeling showed that the higher current was necessary to maintain the same maximum signal handling, but I don't remember doing IMD before/after measurements to verify that. Obviously, Elecraft feel that the device can handle the extra signal without increasing current.

Larry N8LP

Don Wilhelm-4 wrote

Joe,

Are you making an assumption that the P3 input impedance is 50 ohms?
That may or may not be true. I don't know the design parameters of the
P3, but it certainly occurs to me that it is not necessary to use a 50
ohm input impedance.

Yes, SDR-IQ and LP-PAN have the 50 ohm input, so connecting those
devices to the K3 IF Out would cause loss.

73,
Don W3FPR

Joe Subich, W4TV wrote:
>
>> A 50-ohm match is not required in any case.
>>
>
> That’s not exactly true. With devices like LP-Pan or
> SDR-IQ that have 50 Ohm inputs connected to what is a
> high impedance output, the transfer loss (antenna to
> IF) was still in the range of -6dB even with the N8LP
> modification. The rest of the solution was to use a
> Clifton Labs Z-10000 buffer amplifier (high impedance
> input) in a unity gain configuration, install a 4:1 or
> 9:1 (step down) transformer, or modify the SDR-IQ for
> a 200 Ohm input.
>
> 73,
>
> ... Joe, W4TV
>
>
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html