In my humble opinion, I would say PSK, generally, has it "all over" RTTY.
Communication can be maintained with very marginal signals, and very nearby
signals (unless they are "dirty" or overpowering the receiver's AGC system).
I have used a lot of RTTY systems over the years and they require MORE
bandwidth, more power for effective communication (generally), and subject
nearby signals more interference (generally).
The largest "bug" I have found in the PSK system is that it is "mangled" by
propagation phase shifts caused by auroral disturbances even though audibly,
the signal sounds "OK".
I consider this acceptable as it (PSK31) seems to "get through" much more
efficiently than RTTY with less power. Speed in this case not a factor in
keyboard to keyboard QSO's.
I can see no sense in using MORE bandwidth than a PSK31 signal to convey
normal QSO information. Other modes capable of data and image communication
in addition to normal keyboard QSO's wind up being gross "overkill" and use
spectrum space a lot more inefficiently. Spectrum space for CW, digital
modes is "shrinking" from demands made for voice and wide data modes.
Therefore it would behoove us to contrate our efforts on the narrowest
digital mode that will give satisfactory communication in these days of
decreasing spectrum space. An amazing amount of use is being made of just a
3-5 Khz. "sub band" for PSK operations on most bands from 80-10 meters. It
amazes me why this mode isn't replacing RTTY, and remains a popular FSK
mode. It would be like comparing effectiveness of SSB voice mode to the
older AM voice mode. I can't see people changing over to AM, even as a
"fad", over SSB operations. It's starkly obvious which is generally
superior!
My "two pennies" worth on this thread.
73,
Sandy W5TVW
----- Original Message -----
From: "Brian Lloyd" <[EMAIL PROTECTED]>
To: "J F" <[EMAIL PROTECTED]>
Cc: "Elecraft Discussion List" <elecraft@mailman.qth.net>
Sent: Tuesday, May 15, 2007 1:09 PM
Subject: [Elecraft] RTTY vs. PSK31 (was: OT - 73 Magazine (was H mode
mixer))
Whether is PSK or another protocol, is to be
seen. Judging by the numbers of participants in RTTY
contests these days, it is a fast growing segment.
Change is good, unsettling yes, but the possibilities
are worth the uncertainty...
CW remains a mainstay because it is an efficient mode. You can
communicate with very low power levels which makes QRP reasonable. RTTY
is not nearly so efficient and requires much more energy per bit to get
good copy. It forces you into more QRO operation. PSK31 is as narrow as
CW which lets you use narrow filters to lower the noise energy in the
passband. It also incorporates forward error correction which allows it
to still give good copy with very marginal signals.
Now that is not to say that PSK31 is the be-all and end-all for casual
QSOs but I personally think that it is the first of some very interesting
modulation schemes that will provide the same level of performance as CW.
And since new hams don't have to know the code anymore ...
73 de Brian, WB6RQN
Brian Lloyd - brian HYPHEN wb6rqn AT lloyd DOT com
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