The K3 uses the NORMAL setting in CONFIG: SMTR MD as the default. Apparently the PRE/ATT settings are injected before the S-meter circuit in this mode. This means the S-meter reading increases with pre-amplification and decreases with antenuation. In the ABSOLUTE mode the PRE/ATT settings are apparently injected after the S-meter circuit. The S-meter reading is not affected by PRE/ATT settings in the ABSOLUTE mode. It seems to me that the ABSOLUTE mode should be the default mode. The Omni VII S-meter works in a similar fashion to the K3 ABSOLUTE mode. It looks like the Omni VII injects PRE/ATTN before the S-meter circuit but compensates the S-meter by reducing the S-meter display reading with PRE and increasing it with ATTN. When changing the SMTR MD to ABSOLUTE in the K3 I found no difference in the S-meter readings as I switched between NORMAL and ABSOLUTE without PRE/ATT engaged, so I did not feel it was necessary to recalibrate SMTR OF or SMTR SC. The Owner's Manual states: In most cases the default parameter values will provide adequate S-meter accuracy. I believe the ABSOLUTE mode is the way S-meters will be set up in future radios. I thought Rob Sherwood had some interesting comments on this:
The K3 has an unusually useful and linear meter. The Flex 5000 also has a extremely linear S meter, which can also measure in dBm. The Flex approaches the accuracy of a power meter. The Omni-VII S meter is also quite linear, and its S meter readings do not change when you enable the attenuator (6, 12 or 18 dB) or the preamp. This is the way an S meter should work. They other guy's signal is not stronger with the preamp "on", or weaker with the attenuator "on". With the advent of DSP, with most anything possible to be programmed into the operation of the radio, one would hope the OEMs would follow the lead of Ten-Tec or Flex in this matter. Then if you were doing an antenna A/B comparison, the difference in S meter reading would really mean something. I once gave a guy on 15 meters a signal report of S9 + 5 dB, with the preamp off. He did not like that at all, and he asked me to turn on the preamp. He was then 15 over, and he was happy. How silly, his signal had not changed! 73, Rob, NC0B Roy Morris W4WFB K3 #323 _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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
