Re: K3: IF output buffer gain modification
Posted by
alorona on
Sep 23, 2009; 7:11am
URL: http://elecraft.85.s1.nabble.com/K3-IF-output-buffer-gain-modification-tp3690284p3697980.html
> We just bought a new spectrum analyzer from Agilent which
> with all the options we got only cost around 55,000. This unit
> is an N9020A and its very accurate.
Yes, that's a beautiful instrument, Brett. I guess my comments were directed toward the 1000's of older conventional analyzers out there. However, it is still instructive to temper your (Agilent's) claims for absolute accuracy a little bit. Allow me to be a real stickler for a moment:
The +/- 0.23 dB spec is what Agilent calls the "95th percentile" spec, meaning that 95% of the units will probably meet it. But it is not guaranteed. Furthermore, the data sheet for that signal analyzer says that the guaranteed spec is:
+/- 0.33 dB + 0.6 dB frequency response error below 10 MHz = approx. +/- 1 dB. So this is closer to the spec that I would quote someone. Note that I'm not adding in the uncertainty due to mismatch (which appears to be 1.2:1 at the instrument's input in the HF range).
Note that that analyzer also calibrates itself *after every sweep* with an internal power meter!
Yours may be really close to your power meter's reading, but if you didn't have that power meter to tell you that, your uncertainty would have been the figure I gave above.
I loved your "only $55,000" comment. :^)
Regards,
Al W6LX
______________________________________________________________
Elecraft mailing list
Home:
http://mailman.qth.net/mailman/listinfo/elecraftHelp:
http://mailman.qth.net/mmfaq.htmPost: mailto:
[hidden email]
This list hosted by:
http://www.qsl.netPlease help support this email list:
http://www.qsl.net/donate.html