Guy, I too would like that capability, *but* it would not make sense to use the K3 this way unless it has the long term gain stability (including vs. temperature changes) to support it. In response to my raising that issue, Geoff (GM4ESD) emailed me off list to suggest that the J-FET used used in the K3 signal chain before the DSP (used in the hardware AGC loop unless I am mistaken) may be a source of gain variation with temperature. On the other hand, I would think that the K3 receive gain would be more stable against temperature variations than an analog receiver that might have many more stages that are susceptible. I don't know if the K3 hardware is stable enough to be used as a calibrated uV meter. If it is, then no doubt we will eventually see software and firmware to make use of it. If not, then I would not fault Wayne, since a designer cannot please everybody, and he must design for the goals that make economic sense to him.
It has been pointed out that some software defined receivers (presumably without analog stages) can function well as calibrated signal strenght meters for received signals. Personally I would want something like that anyway, for the panoramic reception capability, so that makes me less impatient for the K3 to be proven as or disproven as a precision RF voltmeter. (I would still like to have a high-resolution S-meter, though, inaccurate or not. Thanks Don Rasmussen for sharing your approach.). I have a SoftRock Lite in the pipeline for a first panadapter attempt. The price of that is so low that it isn't very important whether it is good enough or not. If it is not, I will just move on to something better. It would be interesting to know what you give up if you get, say, an SDR-IQ vs. a Perseus. Of course the LP-Pan is also an alternative. 73, Erik K7TV I'd like to be able to calibrate it to 1 uV and 50 uV and know that the noise on the band is -10 or +3 dBuV and that the signal from a friend has gone down to +18 from +26 last week and previous. That requires a calibration, and while one could just use what the rig does naturally as a reference, the K3 has changing SDR code, and maintaining a calibration on a reference source sure does simplify things. To another objection earlier in the thread, inexpensive test equipment doesn't have selectability to narrow down on a single CW signal. So I'm looking at the firmware only abilities (not hardware) of a K3 to do something that has always been a bear. Other SDR's have it, so I figure Wayne will get to it in time, and I will have a piece of on-the-air test gear that I've never had, and prior to now couldn't get without taking out a mortgage. 73, Guy. -- View this message in context: http://n2.nabble.com/Bigger-K3-S-meter-tp1399030p1442642.html Sent from the Elecraft mailing list archive at Nabble.com. _______________________________________________ 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
