On Feb 22, 2005, at 11:43 AM, Andrew Moore wrote:
Has anyone been successful in pushing the K2 beyond the 70 WPM external
keying limit for CW operation?
At 60 wpm, each element is 20 ms long. Given a 5 ms rise and fall time
(assuming you've made the key-click mod), that's only 10ms of
full-power signal. Going much faster than this may be impractical.
Certainly the initial element is going to get clipped severely, and the
K2 does not support CW PTT to prevent this. (This is probably a good
request for the next revision of firmware -- but it would mean the
internal keyer would be disabled)
100 wpm, elements are only 12 ms long - barely 2 ms at full output. At
that speed, I'd begin to wonder about the group delay response of the
remote receiver's filters....
Does it adhere to spec (70 WPM) or
differ in practice? Anyone try any hardware or firmware mods to bump
up
the speed? I'd love for this great high performance CW rig (or even
the
K1 or KX1, despite the QRPish nature of them) to be able to handle up
to
100 WPM.
Here's my question - what person can copy 100 wpm? Only a handful of
people in the world can copy 60 wpm!
If this is meant for machine copy, then perhaps it is time to look at
the lesson learned by the early HF RTTY users in the 1950s. At the
time, FSK wasn't legal. These guys were running RTTY using OOK. It
worked, but copy was poor.
In theory, FSK has a 2 dB advantage over OOK in the presence of
Gaussian noise. PSK has an additional 2 dB advantage over FSK.
The bottom line -- if you are looking to run a 100 wpm data link on HF,
there are a lot more robust methods of modulation than OOK - CW. FSK is
gobs better, and you can run it up to 300 baud (using CW keying between
mark and space, this would be 360 wpm, as 60 wpm is 50 baud)
Bill Coleman, AA4LR, PP-ASEL Mail: [EMAIL PROTECTED]
Quote: "Not within a thousand years will man ever fly!"
-- Wilbur Wright, 1901
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