On 10/15/2016 2:02 AM, Lee - N2LEE via RTTY wrote:
But the issue is NOT bandwidth it is getting rid of the archaic
SymbolRate limit.
The issue isn't the symbol rate. To paraphrase Bill Clinton, "it's
the bandwidth, stupid!"
A 2.8 KHz digital signal requires a 3 KHz receive bandwidth. The noise
power in that 3 KHz is 10 dB greater than that in the average CW/RTTY
bandwidth. An operator using one of the "multiple, open source," open
protocols simply *can not hear* the weaker CW/RTTYPSK31, etc. signals
to avoid interference *even if he were listening to the receiver audio*
which most PACTOR operators do not.
The solution is to eliminate the archaic division between CW/RTTY/DATA
and Voice/Image and allow narrow bandwidth signals up to 400 Hz in the
spectrum where RTTY/DATA is currently permitted and allow signals up
to 2.8 KHz in bandwidth in the current HF Voice/Image spectrum.
If one couples that with rules that require automatically controlled
stations to have and use effective "channel busy" detectors and any
locally or remotely controlled stations to have and use visual means
of displaying any signals present in the occupied bandwidth (e.g.,
waterfall or spectrum analyzer), the issue of symbol rate would be
moot.
Unfortunately, ARRL chose to "treat the pain" rather than address the
disease itself. Like many cases where opiates are prescribed, the
"cure" is going to be far worse than the disease itself.
Also, by removing the 300 baud symbol rate the US would be brought
inline with every other country. For example Canada and Mexico use
the same HF frequencies we do but are not limited by symbol rate. So
if this were and issue it would already bea problem.
Canada and Mexico, along with most of the rest of the world except
Japan, do not have the archaic RTTY/DATA vs. Voice/Image rules. Note
that the rest of the world except Japan have fewer amateur licensees
*combined* than the US. Eliminating the emission limitations while
maintaining bandwidth limitations will be a far superior long-term
solution.
Personally I think arguing against this change sounds a lot like
AMers who complained about SSB. Higher data rates are enviable. We
have become a data oriented society.
If you believe that, remove speed and weight limits on all roadways
- including those in school zones. After all, we are and have been
for 80 years an automobile oriented society.
73,
... Joe, W4TV
On 10/15/2016 2:02 AM, Lee - N2LEE via RTTY wrote:
Bill, I am probably the odd man out here because I believe the FCC should adopt
this change.
But the issue is NOT bandwidth it is getting rid of the archaic Symbol Rate
limit.
Right now all data modes on HF are limited by 300 baud symbol rate. This means
that as new
compression and transfer protocols are developed we would be prevented from
using them
even if they use the exact same bandwidth we are using now.
Also, by removing the 300 baud symbol rate the US would be brought inline with
every other
country. For example Canada and Mexico use the same HF frequencies we do but
are not
limited by symbol rate. So if this were and issue it would already be a problem. Which
it isn’t.
There is an awful lot of Chicken Little scare tactics and hyperbole about this
topic.
There is a need for the Amateur Service to move forward and allowing some form
of increased
symbol rate is overdue. CW, RTTY and narrow band JT modes are not going to
change. But there
is more and more of a need to transfer emergency traffic quickly and
efficiently when cell and internet
services are not available.
Right we are limited to Packet and PSK-Mail at 300 baud but there are multiple
open source, government standards and commercial protocols that can
transfer 5 times the data in the exact same bandwidth.
Personally I think arguing against this change sounds a lot like AMers who
complained about SSB. Higher data rates are enviable. We have become a data
oriented society.
$.02
Lee - N2LEE
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