[Elecraft] K3 Future Factory Hardware Updates; + New beta f/w release 3.27

[Joe Subich, W4TV]

> 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 
  



> -----Original Message-----
> From: Alan Bloom [mailto:n1al at cds1.net] 
> Sent: Tuesday, August 25, 2009 4:17 PM
> To: lists at subich.com
> Cc: 'Eric Swartz - WA6HHQ, Elecraft'; elecraft at mailman.qth.net
> 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: elecraft-bounces at mailman.qth.net
> > > [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Eric 
> > > Swartz - WA6HHQ, Elecraft
> > > Sent: Tuesday, August 25, 2009 1:53 PM
> > > To: elecraft at mailman.qth.net
> > > 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
> > > >   
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