I would think that my old TS-450 must be pretty clean because it seems
like just about every RTTY contest I get in, I can be CQ'ing and someone
will move in right next to me, inside my 250 cycle passband. I figure
it must be someone with a new 'state of the art' rig that can screw
their passband down to about 150 cycles and then crowd right in next to
me and totally QRM me, while not even knowing I'm there.
Sometimes I just wish there was somewhere I could set mine wide enough
to get their attention.
Maybe what we need is some organization to set up a 'cash for dirty
rigs' like they did with the 'cash for clunkers' program. I'd be glad
to swap my TS-450 for a K-3 :-) 73
Tom W7WHY
On 10/20/2014 10:43 PM, Jim Brown wrote:
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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