In between slow periods in IOTA today, (and there are a LOT when you're
on the west coast) I did this. Here's the graph. The closer the curve
is to the bottom of the graph, the cleaner the radio.
k9yc.com/TXPhaseNoise-1.png
As was noted. these plots is the noise in a 1 Hz bandwidth. Most of us
listen to CW with 400 Hz filters, and SSB with about 2.8 kHz, so we'll
hear the sum of all those 1 Hz pieces. This is only the contribution of
phase noise to what you hear off frequency. There's also distortion,
both at audio and RF, and clicks.
Rick's team are definitely not wrong in their assessment of the TS590.
The best you can say about it is that it's not quite as bad as the
IC7600 that my neighbor uses to drive a legal limit amp. He's also a
retired NY lawyer, with attitude to match.
73, Jim K9YC
On 7/26/2014 3:21 PM, Jim Brown wrote:
To compare the radios, you've got to pick values off each graph and
plot them on the same graph. These graphs are printed to different
scales and the scales are more scrunched than they should be, so it
takes practice to get within a dB or two.
These are plots of phase noise (see the test procedures manual). The
measurement bandwidth for the dB value shown is not specified. Phase
noise is the whooshing sound you hear when another TX is keyed. You
hear your own phase noise as well as that of your neighbors.
Note that phase noise performance is different on RX and TX, depending
on the design of the rig. Thanks to Rob Sherwood's RX testing, mfrs
have been working on improving their performance. But because
relatively little attention has been paid to TX trash, that hasn't
happened.
73, Jim K9YC
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