Ok so I decided to do the IF mod as the P3 will be ordered when it comes out and I'd like the increased sensitivity. I'm copying elecraft and K3 support cause I wanted to ask a simple question (as well as share the results). First my question, I didn't have any 13K ohm resistors in 0805 size. So I put an 0603 resistor on the same pads. Will this be ample or should I replace it with an 0805 for power rating reasons?
I made measurements before and after the modification and collected results which I figured I'd share. Signal Generator was a Rhode and Schwartz (sp?) model number unknown. This signal generator was uncalibrated. However the spectrum analyzer I was using was a very recently calibrated N9020A which our cal report gave a clean bill of health and an absolute accuracy of 0.009dBm at -50dBm. Agilent didn't specify the accuracy at -70 but it was getting tighter as the amplitude went lower. I did not engage the preamp in the analyzer. I was making my measurements at -70dBm as its a "common ham amplitude". I injected the signal at 7.040Mhz (cause I use that w/ my XG2 a lot) @ -70dBm. This input was verified on the spectrum analyzer at the end of my cable to calibrate cable losses out of the system. I then measured the output at the IF OUT port at 8.215Mhz. Before PreAmp off: -88.2dBm PreAmp on: -77.0dBm After PreAmp off: -77.9dBm PreAmp on: -66.9dBm Looks like there is a tad bit of loss with the PA off (7.9dB) but then again there is 3.1dB of gain with the PA on... Hopefully this jives with intended results. If not hopefully its a useful data point. Respectfully ~Brett (KC7OTG) ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
