Andy’s point that the KXUSB actually has 0 to 5V output on its TxD line is
correct. This is most likely the limiter in how long of a cable you can have
between the KXUSB and the KAT500.
The actual length is probably best derived by trial and error. As K9YC points
out, the rise and fall times of
Hi Al;
Strange, check for corrupt FPF, here are my notes.
Keith WE6R K3/K4 Tech
Corrupt FPF, confirmed by looking at the Config menu item “XV1” then
tapping 9 and looking for strange entries for XV9, RF or IF usually have
weird values, (144 and 28 are the default).
Check that ADC ref is NOT
On 11/28/2023 6:46 AM, Andy Durbin wrote:
Isn't it true that the KAT500 USB cable uses RS-232 protocol but TTL signal
levels? T
RS-232 is NOT a matched transmission line -- it's a low-Z source and
high-Z input. The limitation on line length is not signal strength, but
rounding of the
Scope traces for a typical KAT500 serial data interface can be found here -
https://www.dropbox.com/scl/fi/ypk0ks16rl03d55ugm4t9/KAT500-signal-levels.pdf?rlkey=7iahis4xp0jnua3c8s577cxjq=0
I can also confirm that KAT500 works just fine when interfaced with a genuine
MAX 3232 RS-232 line driver.
Well to be pedantic the RS-232 (EIA-232) spec says the following:
" Valid signals are either in the range of +3 to +15 volts or the range −3 to
−15 volts with respect to the "Common Ground" (GND) pin; consequently, the
range between −3 and +3 volts is not a valid RS-232 level."
So the
WTB K3 KAT3 board used. ni8nj...@gmail.com
Jack, NI8N
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So that everyone reading understands, the KAT500 IS RS-232/IEEE-232 compatible
in its voltage levels. It is NOT TTL (0,5v) compatible.
73, Jack, W6FB
Sent from my iPhone
> On Nov 28, 2023, at 10:14 AM, Andy Durbin wrote:
>
>
> "Indeed, it is NOT true that the KAT500 uses TTL signal levels
"Indeed, it is NOT true that the KAT500 uses TTL signal levels for the serial
port. "
Ah, but I said "Isn't it true that the KAT500 USB cable uses RS-232 protocol
but TTL signal levels? " Perhaps I should have been more specific. My
recollection is that the USB/Serial cable transmits a TTL
Andy, you do a great job of keeping me on my toes. But...
Indeed, it is NOT true that the KAT500 uses TTL signal levels for the serial
port. The KAT500 has voltage translation circuitry that allows for the use of
quasi-RS232 signal levels.
Quasi? Yes, the transmit data goes to +12 Volts, but it
"Yes. At the point for the extension, the signals are RS-232, not USB. You
should be able to use a much longer cable if need-be."
Isn't it true that the KAT500 USB cable uses RS-232 protocol but TTL signal
levels? TTL may not be as tolerant of length extension as true RS-232.
Certainly no
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