[hpsdr] The problem with digital modes

[Brian Lloyd]

On Mon, May 12, 2014 at 5:19 AM, Clyde Washburn <k2ue at rochester.rr.com>wrote:

> ***** High Performance Software Defined Radio Discussion List *****
>
>
> The primary shortcoming of digital modes is that they are spewing out full
> power, and occupying full BW, when the sender is saying or typing NOTHING.
> The compelling advantage of SSB and CW is that they use no space, and cause
> no interference, when there is no intelligence being transmitted.  When
> there are digital modes that have at property I will get more excited about
> them.
>
>
>
That doesn't sound like a problem with the mode but rather with the
operator. I know that when I operate I read and reply in the typeahead
buffer as the text is coming in. That way when the other station stops
transmitting, I am ready to press TX and I have a buffer full ready to go.

For the op who doesn't touch-type then maybe slower, more robust modes make
sense. If you can only type 1 or 2 characters per second because you
hunt-n-peck then one of the slower MFSK modes makes more sense for you.

But SSB has the same problem, i.e. the channel data rate is faster than the
data source. An example:

"Um, W1ABC from W2XYZ. W1ABC from W2XYZ. Fine business old man. Roger on
your fartblaster 9000, giantschlong megapole, LMR400 coax, dow key coax
relay, bencher paddle, D104, East valley righoser interface, Cheapjunk 9000
with Intel i7 four-core processor, 4 gigabytes or RAM, solid state drive,
and power conditioner. Your signal here is still 599 with just a bit of QSB
varying between S9 and 60dB over S9. Hmmm, power output here seems to be
dropping a bit. Looks like my output has dropped from 1500 watts to 1489
watts on peaks. HEEEEEELLLLLOOO, HELLLLLLLLLOOO, <whistle> <whistle> ...
OK, I just retuned the amp and now it is putting out 1500 watts again. Let
me know if you can see any difference in my signal on the next go around.
Hi hi. Roger on your visit to the doctor. That diverticulitus can be real
bad. That diverticulitus can be real bad. Hi hi. Roger about Obama. Roger
about Obama. I agree he should be impeached. <long whistle> Yup, holding
steady at 1500 watts. Back to you old man, W1ABC from W2XYZ. over."

3 kHz of spectrum used, a whole lot of energy consumed, and absolutely no
intelligence transmitted at all. ;-)

-- 
Brian Lloyd, WB6RQN/J79BPL
706 Flightline Drive
Spring Branch, TX 78070
brian at lloyd.com
+1.916.877.5067
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