[Elecraft] US 60 Meter Band Changes Approved by FCC - CW Issues

[Don Wilhelm]

Mike,

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".

Knowing the frequency you are transmitting on has been an FCC 
requirement from day one.  They do not care about your receive 
frequency.  not only that, but the transmit frequency is defined in 
their terms.  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.  You 
did answer that question on your ham exam correctly, did you not - 2.8 
kHz width divided by 2 equals 1.4 kHz, so shift the suppressed carrier 
down by 1.4 kHz.  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 see nothing in the FCC documents that 
provides for a 100 Hz guard band which would increase the effective 
channel width to 3.0 kHz and thus yield a suppressed carrier shift of 
1.5 kHz from the channel center.  Mysteries, mysteries, mysteries - but 
that is the way we are told to do it, and the FCC has not complained so 
far - maybe just "let sleeping dogs lie" is the best recourse.

73,
Don W3FPR

On 11/20/2011 11:22 PM, Mike Morrow wrote:
> Don wrote:
>
>> I actually was responding to a statement made in a post saying that most
>> transceivers shift the TRANSMIT frequency.
> Hi Don.  Well...er...that *might* have been me when I wrote:
>
>> When the transceiver is shifted to CW mode, the receiver frequency typically
>> remains 5357.0 kHz, while the transmitter frequency is shifted up to typically
>> 5357.8 kHz (for 800 Hz CW sidetone).
> :-)
>
>> If there are any that do...
> In my defense, some ancient rigs like the TS-120S and others from 30 years ago
> DO maintain the RECEIVER carrier frequency the same as mode changes are made,
> and maintain TRANSMITTER carrier frequency that same value for LSB and USB.  But
> they shift the transmitter carrier frequency up (and change the displayed frequency)
> by 0.8 kHz during CW transmission.  The TS-120S in CW mode sets the receiver to
> USB mode, say, on 3550.0 kHz, and when the transmitter is keyed, the frequency and
> the display shift to 3550.8 kHz.  The display always shows transmit frequency
> when transmitting, and always shows receive frequency when receiving.  The
> current convention always shows transmit frequency, even while receiving in CW
> mode.
>
> In a way, that process more clearly shows what is happening.  Today, most rigs
> show no change in displayed frequency on CW between transmit and receive.  The
> casual observer knows something is changing frequency, but it's not obvious
> what.
>
>> ...I believe they are in the minority.
> I'm sure you're correct.  Few rigs today follow that convention.  I prefer the
> current convention.
>
> 73,
> Mike / KK5F
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