I connected my SG2 on 40M to K3 antenna 1 and ran an amplitude measurement test on the P3 and find a -4dB difference in expectations.
I tested P3 level readings with K3 antenna tuner in bypass and P3 IF OUT switch set to off, sub receiver off (this is to make sure I am not sharing the antenna). Configuration of K3 per S-meter calibration set up: Preamp on, ATT off, AGC slow, CW mode, bandwidth normalized using 500 Hz filter. K3 has had the IF modification for the P3 by swapping out a surface mount resistor. For 50 uV on SG2 I read -111 dBm on the P3, expected is -107 dBm For 1 uV on SG2 I read -77 dBm on the P3, expected is -73 dBm So I see a -4 dB gain offset at both SG2 settings. The gain offset was larger when I had the P3 IF OUT switch in the wrong position J Would anyone like to speculate where the gain offset is coming from? This is not earthshattering, just curious. 1. SG2 needs a new battery or just isn't accurate enough for this test. (I have a 100 MHz oscilloscope but I don't know about its ability to measure 50 uV) 2. K3 amplitude gain is different than the P3 expects, I did an S-Meter calibration but this shouldn't make a difference. 3. P3 calibration is off 4. I didn't do the test right Preamp in or out, ATT in or out didn't change the readings. I have 500 Hz filter gain set to 4dB but changing this does not affect P3 readings as the P3 tap must precede the filter. AE6WA Mike Scott Tarzana, CA ______________________________________________________________ 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
