On 10/20/2014 2:05 PM, Stuart Phillips wrote:
The FCC publishes required levels of operation for several aspects of radio performance but
is silent on matters like phase noise etc beyond using phrases like “commonly accepted
engineering practice”.
Hi Stu,
As I wrote in TXNoise.pdf,
"FCC Rules 97.307 (a) No amateur station transmission shall occupy more
bandwidth than necessary for the
information rate and emission type being transmitted, in accordance with
good amateur practice. Figure 12
clearly shows that Yaesu and Icom transceivers are using 3 times more
bandwidth than Kenwood and 5 times
more than Elecraft. As I read the Rules, this puts anyone using them in
violation of 97.307 (a)."
Follow my logic. Elecraft, with their K3, have defined "good amateur
practice" with respect to CW. Kenwood's TS590S, less than half the cost
of a K3, is next best, and the modern ICOM and Yeasu rigs are much
worse. I've seen data from Flex for their 6xxx-series rigs putting them
in a class with the K3 for cleanliness, but these data have not been
verified by ARRL. In simple terms, today's ICOM and Yeasu rigs are in
violation because they use MUCH more than the minimum bandwidth needed
for transmission. 97.307 (b) and 97.307 (c) expand upon that standard.
As I see it (and as principal author of all AES Standards on EMC, I have
used similar wording), "good amateur practice" with respect to occupied
bandwidth was specifically written into the Rules to not tie the hands
of innovative designers and allow the State of the Art to advance. Wayne
Burdick, Elecraft chief engineer, showed many (all?) of his cards in an
Appendix to my report. There is no magic there, simply good, innovative
engineering. The methods are available to all.
For years, we were taught that CW bandwidth was related to CW speed,
which is a total falsehood -- CW bandwidth is solely a function of rise
and fall waveforms, distortion in RF stages, including the output, and
phase noise.
73, Jim K9YC
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