The current situation with Pretty Betty using a recent model firmware
and recent driver (neither yet released, all of this in development and
not available on the web site) IN THE MONTH LONG EFFORT ON CW is
producing some results.
Receive to transmit transition performance:
CW performance has been dramatically improved with Pretty Betty using
new firmware and new mechanisms for control of the hardware. It
involved making changes to the firmware in the radio, the generation
code in DttSP, and the GUI code which coordinates it all. We found
numerous synchronization delays and repaired all of them we could so
far. We have the radio hardware switching in under 30ms. The TX is
fully stable with little variability in elements, no truncation of first
element when going from RX to TX in 30ms. It sounds good in monitor and
it sounds good on another receiver.
Transmit to receive performance:
On the reverse side, we have achieved stability of the receive system
by 70ms. Usability (with some transient response still occurring)
happens in 25-30ms depending on the radio. So if we use the standard
measure T=1200/W where T is the length of a morse element in ms and W is
the words per minute, you would miss one dit while the receive system
recovers if the other side was sending ~40 wpm. This is not 60 wpm QSK
performance and no one says any different. We are investigating why
there is a transient to see what can be done about reducing this. If
that is successful, changes to allow for this level of operation must
be made to the AGC code to preserve state where appropriate when you key
and release the key in the radio.
To not miss a dit from someone sending 40 wpm, 1200/40 = 30ms, it has
to switch faster than this The BEST QSK rigs on the market now measure
transient responses and switching times on the order of 20ms which would
allow us to be a real QSK operation at speeds approaching 60 wpm if we
get there. I hope everyone appreciates how much effort a small
company is putting into working on this for the 20 people in these
forums who can operate 40 wpm at anything like QSK level. I know FOUR
but one of them happens to be bald, fat, loud and carry's a big $tick.
;-). Of course, Flex would like to attract NEW purchasers who might not
buy the radio if they are not able to send and receive 60 wpm QSK with
it (irrespective of the fact that if their life depended on it, they
would be dead in less than a couple of dits).
Things are much better and I see more light approaching from the far end
of the coding tunnel.
Bob
N4HY
--
(Co)Author: DttSP, Quiktrak, PowerSDR, GnuRadio
Member: ARRL, AMSAT, AMSAT-DL, TAPR, Packrats,
NJQRP, QRP ARCI, QCWA, FRC.
"the only people for me are the mad ones,
the ones who are mad to live, mad to talk,
mad to be saved, desirous of everything at
the same time, the ones who never yawn or
say a commonplace thing, but burn, burn, burn
like fabulous yellow roman candles" Kerouac
Twitter:rwmcgwier
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