I know this is a wacky idea but...

Would it be at least theoretically possible to transmit digital (hi-fi?)
audio signals using a spark-gap transmitter?


Dave

David Forsyth wrote:
I know this is a wacky idea but...

Would it be at least theoretically possible to transmit digital (hi-fi?)
audio signals using a spark-gap transmitter?

Yes, if you use dash for "1", dot for "0" (or vice versa), _never_
mis-send, and have some unambiguous way to signal EOF, or use
some other coding scheme that unambiguously represents all the
possibilities as stuff that can come out of a spark transmitter. The
EE and mathematicians who know more coding theory than I do will be
better able to answer the question, but _yes_ is the basic answer.

If you want to send it synchronously, then it's even fairly easy,
provided you're prepared to accept a low data rate and do signaling
out-of-band for EOF, End-of-track, and suchlike.

After all, we manage to send images from probes passing Neptune. This
is, by comparison, trivial.

(I'll skip the lecture on Gold codes, sending a 65535-bit PN sequence
straight-up for a "1", inverted for a "0", and all the other stuff
that actually got the bits received with a minimal BER)

Let me know if you want to start sending low-rate digital audio using
your spark-gap transmitter, and I'll move a few thousand miles away.

Related note:

Did anyone else here in the US catch the piece on NPR about Bill
Marconi's first transmission from Poldhu to Newfoundland, about a
week ago? It was sort of spacey and low on information content, but
it _did_ have some stuff in it I hadn't heard before, including audio
of Marconi talking about the problems involved -- including the winds
at Poldhu being so bad that they repeatedly blew the antenna masts
over.

--
Mike Andrews

Tired old sysadmin

On Wed, 10 Dec 2003 23:31:54 +0000 (UTC), Mike Andrews hath writ:

pedantic

Did anyone else here in the US catch the piece on NPR about Bill
Marconi's first transmission from Poldhu to Newfoundland, about a
week ago?

I doubt if Marconi did any transmitting "...about a week ago." g
Your english teacher must be turning over in her grave. :-)

/pedantic

On Wed, 10 Dec 2003 23:31:54 +0000 (UTC), Mike Andrews hath writ:

pedantic

Did anyone else here in the US catch the piece on NPR about Bill
Marconi's first transmission from Poldhu to Newfoundland, about a
week ago?

I doubt if Marconi did any transmitting "...about a week ago." g
Your english teacher must be turning over in her grave. :-)

/pedantic

Yup, speak to any electronic car ignition designer, they will tell you how
accurately you can time a spark.

Clive

yes, but not in real time without going broke..
hank wd5jfr
"David Forsyth" wrote in message
...
I know this is a wacky idea but...

Would it be at least theoretically possible to transmit digital (hi-fi?)
audio signals using a spark-gap transmitter?


Dave

David Forsyth wrote:
I know this is a wacky idea but...

Would it be at least theoretically possible to transmit digital (hi-fi?)
audio signals using a spark-gap transmitter?

Yes, if you use dash for "1", dot for "0" (or vice versa), _never_
mis-send, and have some unambiguous way to signal EOF, or use
some other coding scheme that unambiguously represents all the
possibilities as stuff that can come out of a spark transmitter. The
EE and mathematicians who know more coding theory than I do will be
better able to answer the question, but _yes_ is the basic answer.

If you want to send it synchronously, then it's even fairly easy,
provided you're prepared to accept a low data rate and do signaling
out-of-band for EOF, End-of-track, and suchlike.

After all, we manage to send images from probes passing Neptune. This
is, by comparison, trivial.

(I'll skip the lecture on Gold codes, sending a 65535-bit PN sequence
straight-up for a "1", inverted for a "0", and all the other stuff
that actually got the bits received with a minimal BER)

Let me know if you want to start sending low-rate digital audio using
your spark-gap transmitter, and I'll move a few thousand miles away.

Related note:

Did anyone else here in the US catch the piece on NPR about Bill
Marconi's first transmission from Poldhu to Newfoundland, about a
week ago? It was sort of spacey and low on information content, but
it _did_ have some stuff in it I hadn't heard before, including audio
of Marconi talking about the problems involved -- including the winds
at Poldhu being so bad that they repeatedly blew the antenna masts
over.

--
Mike Andrews

Tired old sysadmin

Yup, speak to any electronic car ignition designer, they will tell you how
accurately you can time a spark.

Clive

yes, but not in real time without going broke..
hank wd5jfr
"David Forsyth" wrote in message
...
I know this is a wacky idea but...

Would it be at least theoretically possible to transmit digital (hi-fi?)
audio signals using a spark-gap transmitter?


Dave

yes it can be done!
make a inteface with pc and sent RTTY.


--
http://www.qsl.net/sv1hao
"David Forsyth" wrote in message
...
I know this is a wacky idea but...

Would it be at least theoretically possible to transmit digital (hi-fi?)
audio signals using a spark-gap transmitter?


Dave