[GreenKeys] Fwd: Re: recording rtty

[Bruce Gentry]

-------- Forwarded Message --------
Subject: 	Re: [GreenKeys] recording rtty
Date: 	Mon, 14 Sep 2015 13:59:14 -0400
From: 	Bruce Gentry <ka2ivy at verizon.net>
To: 	John Beckman <webbeck at comcast.net>



With today's digital recording, I doubt there would be any problem with 
speed/pitch instability. Likewise for a top quality studio or broadcast 
analog recorder. Years ago, the recorders most home users had were 
nominally stable over the short term of a few seconds, but long term  
stablity was poor. I recorded and reproduced fax signals on an Ampex 350 
studio recorder with excellent results.

   Bruce Gentry, KA2IVY


On 9/13/15 2:28 PM, John Beckman wrote:
> Someone recently inquired about recording RTTY pix. Recording the RTTY 
> audio tones and playing them back never did work well, because of 
> audio tape "wobble." In 1978 I built a coder/decoder which worked 
> amazingly well. It converted the tones to pulses and on playback 
> converted the pulses back to tones. Because it produced a number of 
> pulses for each character, if static or interference took out a few 
> pulses it didn't matter because there were plenty left to do the job.
> I used this feeding to and from a UT4 which had a Uart and a number of 
> Fifos. I don't see why it couldn't be interfaced directly to a loop 
> itself.
> If you'd care to see the "ancient" way of doing this, the schematic is at:
> http://www.w4btx.com/recorder.html
> Good luck and 73
> John, W4BTX
> -- 
> For a listing of all my Amazon books and stories please visit: 
> *http://www.johnbeckmanbooks.com*
>
> "Whenever God Closes One Door He Always Opens Another, Even Though 
> Sometimes It's Hell in the Hallway"
>
>
>
> ______________________________________________________________
> GreenKeys mailing list
> Home:http://mailman.qth.net/mailman/listinfo/greenkeys
> Help:http://mailman.qth.net/mmfaq.htm
> Post:mailto:GreenKeys at mailman.qth.net
>
> 2002-to-present greenkeys archive:http://mailman.qth.net/pipermail/greenkeys/
> 1998-to-2001 greenkeys archive:http://mailman.qth.net/archive/greenkeys/greenkeys.html
> Randy Guttery's 2001-to-2009 GreenKeys Search Tool:http://comcents.com/tty/greenkeyssearch.html
>
> This list hosted by:http://www.qsl.net
> Please help support this email list:http://www.qsl.net/donate.html



-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.qth.net/pipermail/greenkeys/attachments/20150914/87c247ec/attachment.html>