[GreenKeys] Model 19 on ITTY

[Ralph Mowery]

Al, as you will be receiving almost pure audio even a very simple demodulator would work fine.  Here is an example that could be built on one of the solderless breadboards in a very short time.

 

There are other circuits that use a XR2211 IC that are even simpler.

 

http://www.seekic.com/circuit_diagram/Communication_Circuit/UPWARD_SHIFT_RTTY_DEMODULATOR.html

 

 

73

 

Ralph ku4pt

 

From: Al Klase [mailto:ark at ar88.net] 
Sent: Friday, January 24, 2020 9:57 AM
To: Ralph Mowery; greenkeys at mailman.qth.net
Subject: Re: [GreenKeys] Model 19 on ITTY

 

Hi Ralph, et al

The point is we don't have a TU.  We'll be running a PC anyway if we monitor ITTY.  Logic level to current loop isn't a problem, and I've found an Arduino "sketch" that will go from ASCII to baudot.

I'm exploring RTTYT which looks like it will handle the PC chore.  The scheme is complicated by the fact that modern PC's don't have RS-232 ports, and the UART's in the USB dongles don't support 5-bit formats.

73,
Al

 
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