If there aren't going to be that many pactor-4 signals on the air due to
the cost of modems, the signals should have a bandwidth limitation. In
addition there should be a band plan for pactor-4 signals by keeping
them above 100khz from the bottom of the band. I suspect that if
pactor-4 is allowed in the lower portion of the bands that the cost of
modems would come down.
Emergency communications, which are important and luckily don't happen
very often, could be handle above 100khz.
The experimentation idea doesn't hold water either. We know that
sending more data at faster speeds requires more bandwidth. How much
data needs to be sent during an emergency? Amateur frequencies are
intended for amateur use, not commercial use.
Twisting the big knob when a pactor-4 station comes on frequency,
without checking first, is not an option in my book.
That being said, if you don't agree with pactor-4 being allowed in the
cw/rtty sub-bands you better start writing the ARRL and making an
appropriate comment against RM-11708.
Rich - N5ZC
On 8/23/2016 3:43 PM, Ward Silver wrote:
First, I do agree with N9NB that there needs to be a bandwidth limit
in the amateur bands - this has been confirmed by the FCC in numerous
communications and opinions about overly-wide phone signals and also
by 97.307(f)(1) which limits the modulation index of angle-modulated
phone emissions to less than 1 at the highest modulating frequency.
Clearly, the idea of a maximum bandwidth is considered good practice
in the phone sub-bands and a similar limit in the RTTY/data sub-bands
does not need to strangle technical innovation. Nevertheless, it is
not sufficient to rely on the "necessary" and "good practice" wording
in 97.303(1) because neither is strong enough to be meaningful without
creating endless arguments and perceived loopholes. So just place a
reasonable "roofing bandwidth" on amateur radio emissions below 30 MHz
- 3 kHz? 6 kHz? 10 kHz? - and let us sort it out as we do every day!
[If the maximum bandwidths of phone and data signals are to be linked
in one rule, a simple administrative fix could be made by the very
simple change of applying 97.307(f)(2) to all of the HF bands -
renumber it from 97.307(f)(2) to 97.307(g) or add (2) to all of the HF
bands in 97.305. Digital voice would remain confined to the phone
bands because even though it is transmitted as bits, the overall
package is still classified as a phone emission, just as digitized
images are still considered image emissions (facsimile). (See 97.3(c)
and 2.201)]
Let's get a grip, though...in my opinion:
PACTOR 4 is already permitted everywhere else in the world and has not
ruined ham radio yet. PACTOR 3 and PACTOR 4 modems are expensive -
the rush to use >$1000 modems to exchange non-commercial traffic at
<10 kbps (at best less than 1/5th of dial-up rates) over HF is not a
very strong business case. While it is popular to gnash our
collective teeth about those impure "boaters," (Oh, the fiends,
checking their stocks via amateur radio!) the primary use of the
Winlink system is rapidly shifting toward emcomm/public service, which
is prominent in our Basis and Purpose of 97.1(a). Using faster modems
actually reduces band occupancy in terms of Hz-sec for any particular
message - although better performance *might* increase the number of
messages. But at <10 kbps and with the horrible things that HF does
to a channel...I just don't see a stampede materializing.
More importantly, ham radio needs to get with the program - our
over-reliance on decades-old analog modes is laughable. You want new
technical blood to fulfill 97.1(d)? Try explaining to anyone under 40
that our primary HF digital modes run at 31 baud or use the
80-year-old 5-bit Baudot code developed for electromechanical printers
and which can't even handle the full alphanumeric character set.
Inform them of our 300-baud symbol rate limit below 30 MHz and, after
their initial disbelief, you will get a look of pity followed by
complete disinterest. In most student papers at engineering
conferences everything under 1 GHz is considered BASEBAND AUDIO!
Nor is it a good idea to further splinter the ham bands - it just
creates unreasonable expectations of ownership or occupation. Many
operators discovered during the W1AW/portable year how channelized
40/75 meters had effectively become, simply due to squatter's rights.
We are always pooh-poohing band plans during contest weekends -
rightfully - and any kind of reserved-for-narrowband allocation will
simultaneously create the expectation that narrowband signals stay
within it. There is lots of room on the bands for all kinds of
signals if we could only get over the notion of reserved sub-bands,
calling frequencies, net lists, and been-here-for-years. We have these
Big Knob thingies we can use. We're not rockbound any more. Frankly,
I think the whole notion of band plans needs to be greatly
de-emphasized. We are the most flexible telecommunication service of
all - why are we so intent on throwing that away?
Consider the use of "smart spectrum" SDR-based displays showing where
all the signals of various types are and aren't. (The RBN almost does
that now...) With so many different modes and more on the way, it
seems to me that approach is a better way of going forward in line
with the "cognitive radio" approach to spectrum management and our
mandate in 97.1(b) and (c). Alternatively, if the bands are going to
be segregated, then do it according to behavior (see my Contest Update
editorials of Sep/Oct 2005) which is the root cause of most inter-mode
conflicts, anyway.
A real problem that has been identified by many, and which is
something we really *do* need to address for *all* modes, is
transmitter linearity and noise. We have fantastic receivers that can
hear a skeeter fart but the bands are full of our own trash from
non-linear and noisy transmitters - even the expensive ones. (That we
are still dealing with key clicks in the year 2016 is ridiculous.)
There are plenty of techniques that we could adapt from the wireless
data industry, such as pre-distortion and higher-voltage final
transistors, all well-characterized mature technologies. The
linearity issues with complex I/Q data signals are the same as for
speech modulation. Let us solve noise and transmitter IMD and it will
be a lot easier for everybody to get along. Digital modes can be a lot
more noise-tolerant, too, and that might help a lot with the new
reality of all spectrum, just as FM was invented by Armstrong in
response to AM static.
Also...this CW...I turn on my radio most weekdays and wonder where is
this precious commodity we are trying to preserve? Sure - contest
weekends sure load up the bands - but the other 90%+ of the time the
CW areas are pretty empty. I love CW but I am not of the opinion that
we have to hobble the service and keep it increasingly technically
irrelevant in order to preserve a century-old mode that isn't the
backbone of the service it once was.
The sky is not going to fall. Yes, I will swear like a sailor when a
data signal wipes out my CW run frequency, but then I'll use my Big
Knob and start again somewhere else. (Or just stay there and duke it
out.) Ham radio needs to accommodate useful data modes if it is going
to survive to celebrate its second century.
73, Ward N0AX
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