Hi Bill,
Thanks for confirming my thinking. Linear amplification would not be
popular due to higher initial cost and greatly reduced efficiency.
You are correct that long periods of time to transmit the sender's call
sign is nothing new. Single frequency QRSS used to be common with dot=60
seconds, dash=180 seconds. Dual frequency QRSS (DFCW) with dot and dash
as long as 120 seconds each has been used; 60 and 90 seconds per
dot/dash are more common in recent times. There are other modes which
fall into this category as well.
73,
Paul N1BUG
On 9/28/20 11:05 AM, Bill Somerville wrote:
Hi Paul,
you are correct, sending a side-tone for CW identification is a
non-starter for a mode that is designed to utilize a constant envelope
type of modulation. Apart from that requiring users to use linear
amplification, quite an ask when expecting to utilize up to half hour
transmissions using aerial with no better than 1% efficiency and the
necessary high input power required to get even close to the usual 1W
EIRP limits. Extra bandwidth used for the extra tone and the mixing
products with the wanted data signal would also be unwelcome.
I note also that the length of time to successfully transmit the senders
callsign cannot be a new issue, QRSS techniques have surely already been
used that take several tens of minutes to complete a callsign
transmission. A quick Goole search says that QRSS rates as slow as one
minute per dot/dash (dual frequency keying) have been successfully employed.
73
Bill
G4WJS.
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