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-boun...@mailman.qth.net > > [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Eric > > Swartz - WA6HHQ, Elecraft > > Sent: Tuesday, August 25, 2009 1:53 PM > > To: elecraft@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 > > > > > ______________________________________________________________ > > 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 > > ______________________________________________________________ > 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 ______________________________________________________________ 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
