I picked up an XG1 oscillator kit at the Elecraft booth at the DX convention in Visalia. Assembled it this morning and used it's 50 uV setting to check the S-meters in my four HF radios with the following results:
Elecraft K2/100 = S9 (digital S-meter) (S-meter was calibrated by adjusting the value of R1 for best AGC action and using the S-meter calibration procedure described in the manual, i.e., full scale = RF gain fully CCW and S0 = RF gain fully CW with antenna disconnected -- apparently done this way, there is no need to calibrate S9 on the meter using the method described by others on this e-mail reflector). Yaesu FT-1000MP = S9 (main and sub rx's, digital S-meters) Icom IC-756Pro3 = S9+3 dB (analog S-meter), S9 (digital S-meter) Kenwood TS-830S = S9+3 dB (analog S-meter) (1 uV setting = S4) Years ago I calibrated the S-meter in the TS-830S using a metrology lab calibrated HP-610C signal generator. I surmise that the Icom's S-meter was factory calibrated at S9 using 50 uV. I therefore believe the -73 dBm output of the my XG1 is actually -70 dBm (70.7 uV). If the 50 uV setting on the XG1 is actually -70 dBm, then the 1 uV setting should be down another 34 dB, or -104 dBm (1.414 uV). Interestingly, only the Kenwood has an accurate S-meter for signal levels below S9. It's S-meter reading with the XG1 set for 1 uV was S4 (all other radios were S0). Based on the 6 dB "standard" that each S-unit = 6 dB (and -73 dBm = S9) means that S4 is a signal level of -103 dBm, which agrees quite closely with the presumed -104 dBm output of the XG1 at the 1 uV setting. When I get ambitious, I'll perform the procedure for determining the noise floor of each receiver as described in the XG1 manual. All in all, the XG-1 is a neat piece of test equipment to add to the shack and, as the saying goes, "Good enough for government work." 73, de Earl, K6SE _______________________________________________ Elecraft mailing list Post to: [email protected] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
