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Old January 25th 14, 06:10 AM posted to rec.radio.amateur.antenna
Jeff Liebermann[_2_] Jeff Liebermann[_2_] is offline
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Default Relationship Between Antenna Efficiency and Received Signal Strength

On Fri, 24 Jan 2014 20:29:22 -0500, Jerry Stuckle
wrote:

Receiver sensitivity was 0.2 mv for 20db S+N/N ratio.


I'll assume that you mean 0.2 microvolts, not millivolts.
Also, nobody has uses 20dB S+N/N since about the 1960's except maybe
the ARRL[1]. 12dB SINAD has been around since about the mid 1960's.
http://en.wikipedia.org/wiki/SINAD

I don't know
how much better; the surplus signal generator I was using wasn't that
accurate.


At the time, I used a Gertsch FM-something. It's the box with only
the left handle showing at the extreme right of the pictu
http://802.11junk.com/jeffl/pics/Old%20Repeaters/slides/PMC02.html
It wasn't every accurate, and not really intended to be used as a
signal source. However, I had a precision step attenuator, and since
the Gertsch factory was near my parents house, it wasn't too difficult
to get it calibrated in trade for some grunt work.

And BTW - 'm' can also mean micro, especially when you don't have a
Greek alphabet available. 'u' is not the same as the Greek 'mu' and can
be confusing. Of course, using 'm' for both milli and micro can be
confusing, unless you know the context.


If you follow SI standards, the "m" means milli.
http://physics.nist.gov/cuu/Units/prefixes.html

If you have a PC keyboard, try using the key combination:
alt0181
on the number pad which produces a µ symbol.
http://symbolcodes.tlt.psu.edu/accents/codealt.html


[1] It took me about 10 years to stop using micro-microfarads and
switch to picofarads. I suppose there might be some dinosaurs roaming
the earth still talking about "20 dB quieting".

--
Jeff Liebermann
150 Felker St #D
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Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558