[Elecraft] US 60 Meter Band Changes Approved by FCC - CW Issues
Fred Jensen
k6dgw at foothill.net
Mon Nov 21 00:47:56 EST 2011
On 11/20/2011 8:45 PM, Don Wilhelm wrote:
> This new ruling (when it takes effect) amplifies the cardinal rule -
> "User, know your transceiver and how it handles both the transmit and
> receive frequencies for all modes".
Yeppers, just like it's always been.
> We hams use the SSB suppressed carrier frequency,, but (at
> least for 60 meters), the FCC regs refer to the center channel frequency
> - the suppressed carrier frequency is left for us to figure out.
That's pretty standard on the planet, except for us. But then in our
defense, no one "tunes around the band" like we do ... indeed, most
can't "tune" at all.
> NOW, I can't resolve why everyone uses a downward
> shift of 1.5 kHz instead of a shift of 1.4 kHz - perhaps someone can
> explain that difference to me.
I suspect it comes from the fact that a single-channel analog audio
radiotelephone baseband generally is considered to extend from 300 to
about 2500 or so Hz, give or take a little on each end. So, in the
rules, the FCC "helped us out," and told us where to put our suppressed
carrier [what most of our radios show us] such that our RF signal will
be more or less centered in the channel allocation after our transmitter
processes the baseband.
Or ... maybe not, but the math does work out :-)
One big thing we ALL need to understand: As currently proposed, the new
CW and digital modes are also to be centered. It says so, and in the
discussion, the Commission explains why they did not accept the ARRL
recommendation that the channel be treated as a 2.8 KHz "ham band" for
PSK purposes. The good news: We started with 5 USB channels, NTIA
agreed to swap one for another channel with less primary user activity,
and to give us both CW and digital use. If we behave with this as we
apparently have with USB-only, we might get more. 5 MHz is a really
cool spectrum, quite different than 7 or 3.5 MHz, that's probably why
the NTIA/FCC feel somewhat protective of it.
73,
Fred K6DGW
- Northern California Contest Club
- CU in the 2012 Cal QSO Party 6-7 Oct 2012
- www.cqp.org
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