Nicely done, Jim.
Since I have an O II, I looked at that one first. I see the O II shows
the lowest phase noise out to about 2.5 kHz, where it matched the K3,
then heads the wrong way. It's #2 to about 7.5 kHz and then is among the
worst (THE worst) at 50 kHz. At 300 kHz, it's still worse that the IC7600.
The TS-590 and Eagle comparisons are interesting, too: close in, the
Eagle is 10 dB better than the '590, but the phase noise difference
vanishes and they two are in a dead heat by 5 kHz from the carrier. The
Eagle is better by ~10 dB at 10 kHz, but the two become essentially
identical by 11 kHz.
The K3 monotonically decreases with separation from the carrier and does
it at a steep rate -- well done!
I know that there's more to the overall "stuff" generated by
transmitters, but the phase noise characteristics of the K3 with
frequency are quite impressive.
How might we look at a total noise figure? Phase noise is in dBC/Hz, so
we can't simply sum it with things like IMD. Should we integrate the
phase noise power as a function of bandwidth, so that we can look at the
phase noise power for CW and SSB (pick a defining bandwidths)? How,
then, do we handle the other noise sources that don't integrate as
nicely across the pass band?
Perhaps there's no single number that we can generate -- each represents
a different "dimension" of the total problem.
Kim N5OP
On 7/27/2014 3:45 PM, Jim Brown wrote:
The title says it all -- Rick asked for it, and I did it this morning,
changing the frequency axis to log and moving labels around. I also
added data for the new IC7100, a do everything cheapie with a remote
head, just reviewed in July QST.
k9yc.com/TXPhaseNoise-1MHz.png
For the Field Day problem, look at the data around 200-300 kHz --
that's what we run into when we run CW and SSB on the same band.
There's 15 dB difference between the IC7100 and the IC7600/TS590, and
the K3 is another 17 dB better than the best of those!
And, as I noted in an earlier post, this is only one part of the
problem -- there's also IMD on both TX and RX, clicks, audio
distortion, and RX phase noise. This stuff CANNOT be filtered -- it's
all "in band."
Now I'm going to tackle the key click data.
73, Jim K9YC
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--
Kim Elmore, Ph.D. (Adj. Assoc. Prof., OU School of Meteorology, CCM, PP
SEL/MEL/Glider, N5OP, 2nd Class Radiotelegraph, GROL)
/"In theory there is no difference between theory and practice. But, in
practice, there is." //-- Attributed to many people; it's so true that
it doesn't matter who said it./
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