Your are right, Julian. The current regulations mostly protect phone
users from interference by other modes and digital users are left to
figure out how to share what space is left. The division is
approximately 50-50 between phone and digital "what the FCC calls
'data/RTTY'". This is a holdover from the days when the only digital
mode was CW and the only data mode was RTTY.
Phone is the easiest to use human/rig interface, and the easiest to
learn, so it is the preferred interface for most. Using 20m as an
example, 150 kHz is allocated to RTTY/data (digital) and 200 kHz to
phone. Assuming a 2.2kHz wide phone mode, there is room for
approximately 90 phone stations. Assuming an average of 0.5 kHz wide
digital modes, there is room for 300 digital stations. If everybody used
a 2.2 kHz wide digital mode, there would only be room for 68 digital
stations.
CW is still the most-used digital mode, about .2 kHz wide, depending
upon the speed, then RTTY, and now, PSK31, are next, and all the other
digital modes have to make do with whatever space is left.
The phone operators could complain that THEY are the second-class
citizens and have not been allocated enough space in proportion to their
numbers!
What is really needed is digital voice in a more narrow bandwidth,
instead of "CD" quality digital voice with a bandwidth of 2200 Hz,
because there simply is not enough space for everyone to use wide modes
of any kind. That is already possible today by combining speech-to-text
with text-to-speech, but the voice is not your "own", but synthesized
voice. Dragon Software's "Naturally Speaking" 10 is now good enough
speech-to-text with about a 1% error rate with enough training, and my
DigiTalk program for the blind ham will speak the incoming PSK31 text as
fast as it comes in, so that is essentially "phone" in a 50 Hz
bandwidth, but without your "own" voice, and unnaturally slow speaking.
73 - Skip KH6TY
g4ilo wrote:
I'm not sure I follow this argument. The fundamental problem is that,
within the area allocated for digital modes, there is not enough space
for many simultaneous contacts to take place using a 2.2kHz wide mode.
This has not hitherto been much of a problem because until now there
has not been much demand for using wide band digital modes. People
live with interference from Pactor etc. because it comes in bursts and
does not completely wreck a QSO.
If "hordes of operators wanted to use ROS" then without the ability
for them to expand upward in frequency the digital modes sub band
would become unusable for anything else. All your current legislation
does is protect the phone users from interference by other modes and
make digital users second class citizens confined to a ghetto where
"anything goes".
Julian, G4ILO
--- In digitalradio@yahoogroups.com
<mailto:digitalradio%40yahoogroups.com>, KH6TY <kh...@...> wrote:
>
> Imagine also if spread spectrum were allowed anywhere in the current
> phone and upper data segments. The complaints about NCDXF and Olivia
QRM
> from ROS would be nothing compared to what it is already if spread
> spectrum were allowed anywhere in the same bandwidth as phone, and
> hordes of operators wanted to use ROS, and not just a relative few.
