Digital data stored/transmitted through low band. mediums.

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Digital data stored/transmitted through low band. mediums.

Postby eli573 » Mon May 08, 2017 2:18 pm

Hello, greetings, etc.
I am asking if there are any programs that enable one to transmit or data over a low bandwidth medium such as an analog phone line or store data over a medium such as cassette tape, specifically the latter. I know this has almost absolutely nothing to do with NBTV, but I guess I could put an MPEG on to a tape and call that NBTV. I can't find any program to do such a thing except KCS08, which involves you going through many loopholes to use and doesn't have a half decent data rate. I'm looking for something that uses a digital modulation technique, such as trellis or even PCM. I've done a quick series of equations here:
56Kbps is PCM dialup which is effectively 53.33Kbps over the phone. Taking the phone line out of the equation, as we should all know that cassette sounds quite a bit better than the phone, this adds those ~3Kbps back, as well as 11Kbps for it's original theoretical limitation (look it up) to 64Kbps. A cassette is obviously stereo, so that's two channels at a time of 64Kbps. 64*2 obviously equals 128. 128Kbps * 60 (seconds per minute) = 7680Kb/minute. 7680Kb/min * 47-- on a 90 min tape, the 45min per side limit is actually 47 minutes. Anyway, 7680Kb/min *47 =360,960 Kb per side. Divide that by 10 for Kb (kilobit) to KB (kilobyte) is 36,096 KB per side. Multiply this by two = 72,192 KB per 90min tape. That is 72MB, it's not a data CD but it's a definite improvement when compared to KCS08. Is this possible, and if so why has no one made a program for it?
eli573
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Re: Digital data stored/transmitted through low band. medium

Postby Harry Dalek » Mon May 08, 2017 5:00 pm

eli573 wrote:Hello, greetings, etc.
I am asking if there are any programs that enable one to transmit or data over a low bandwidth medium such as an analog phone line or store data over a medium such as cassette tape, specifically the latter. I know this has almost absolutely nothing to do with NBTV, but I guess I could put an MPEG on to a tape and call that NBTV. I can't find any program to do such a thing except KCS08, which involves you going through many loopholes to use and doesn't have a half decent data rate. I'm looking for something that uses a digital modulation technique, such as trellis or even PCM. I've done a quick series of equations here:
56Kbps is PCM dialup which is effectively 53.33Kbps over the phone. Taking the phone line out of the equation, as we should all know that cassette sounds quite a bit better than the phone, this adds those ~3Kbps back, as well as 11Kbps for it's original theoretical limitation (look it up) to 64Kbps. A cassette is obviously stereo, so that's two channels at a time of 64Kbps. 64*2 obviously equals 128. 128Kbps * 60 (seconds per minute) = 7680Kb/minute. 7680Kb/min * 47-- on a 90 min tape, the 45min per side limit is actually 47 minutes. Anyway, 7680Kb/min *47 =360,960 Kb per side. Divide that by 10 for Kb (kilobit) to KB (kilobyte) is 36,096 KB per side. Multiply this by two = 72,192 KB per 90min tape. That is 72MB, it's not a data CD but it's a definite improvement when compared to KCS08. Is this possible, and if so why has no one made a program for it?


I came across this .....
FreeDV Digital Voice for HF

Latest version 0.96.5 August 15, 2013
Introduction

FreeDV is a GUI application for Windows and Linux that allows any SSB radio to be used for low bit rate digital voice.

Speech is compressed down to 1400 bit/s then modulated onto a 1100 Hz wide QPSK signal which is sent to the Mic input of a SSB radio. On receive, the signal is received by the SSB radio, then demodulated and decoded by FreeDV.

FreeDV was built by an international team of Radio Amateurs working together on coding, design, user interface and testing. FreeDV is open source software, released under the GNU Public License version 2.1. The FDMDV modem and Codec 2 Speech codec used in FreeDV are also open source.

http://www.g0hwc.com/other_digital.html
http://freedv.org/tiki-index.php

I have never tried it but i would think inputting SSTV or NBTV it should turn that into a digital signal ....if you can transmit it on SW would it not record to tape ?
Well if you try do put it up like to see the results .
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: Digital data stored/transmitted through low band. medium

Postby plicker » Fri Jun 09, 2017 4:46 pm

Yes, try to change inputting signal. That helps
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