Text "Chat" Function?

[K0OG]

Greetings,

It seems it would be a natural extension to include a one-line (SMS-like) text "chat" window in FreeDV.  This would be similar to the text message functionality in Echolink - limited to one-liners, but could be useful to send specific information (e.g., a URL to a web page, etc.).  Is this technically possible within the bandwidth and existing codec limitations?  Is this something others would consider useful?

Thanks to the authors and contributors for a really fun tool and mode!

73,
-Joe-

[Bruce Perens]

The main problem with this at the moment is that there isn't any header. Our codec frame is so small that any significant header would be larger than the data. I guess we'll come up with a creative way to switch modes eventually.

    Thanks

    Bruce

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[Mel Whitten]

Joe

 

You may do that now.. but at a very slow bit rate.  Unless the sigs are quite good, I probably would not recommend it unless you really need to.  :-)

 

Mel

 

--

[John D. Hays]

If you have a web-browser open at the same time, you can 'chat' on http://qso.k7ve.org

---

John D. Hays
K7VE

PO Box 1223, Edmonds, WA 98020-1223 

  

[Mel Whitten]

Yes, much much better alternative.  :-)  and its done all the time.

[Ronny Julian]

Please don't bloat this down.  Chat on PSK.

[Bruce Perens]

I bet you could make PSK work simultaneously with our voice modem on the same radio. You'd have to set the audio center frequency of the PSK carrier just to one side of our modem carriers, mix the audio, and coordinate T/R between the two programs.

    Thanks

    Bruce

On 10/09/2013 11:40 AM, Ronny Julian wrote:

[Steve]

Maybe add one more QPSK carrier to the program and send four bits at 50 baud (200 bps) in an additional 75 Hz BW @1.4 kHz total.

[Bruce Perens]

On 10/09/2013 01:17 PM, Steve wrote:

Maybe add one more QPSK carrier to the program and send four bits at 50 baud (200 bps) in an additional 75 Hz BW @1.4 kHz total.

Well, I like the idea that PSK31 can be decoded with existing software.

[Stuart Longland (VK4MSL)]

This… is a very good point.

PSK31 is widely supported, recognisable by most operators, and also
allows someone who comes across a FreeDV, doesn't know WTF it is, can
contact the FreeDV station by PSK31 and ask.

Interoperability is a good thing. :-)
--
Stuart Longland (aka Redhatter, VK4MSL)

I haven't lost my mind...
...it's backed up on a tape somewhere.

[Steve]

I'm thinking the problem isn't technical, but legal. That is, an incidental Data carrier to a Phone modem would probably be legal, but a Data carrier not incidental, and completely separate from the Phone modem would essentially be operating a Data mode in the Phone/Image band. At least in the USA.

An incidental carrier would have to be at the same symbol rate as the current modem though, is my thinking.

[Tony Langdon]

On 10/10/13 6:41 PM, Steve wrote:
> I'm thinking the problem isn't technical, but legal. That is, an
> incidental Data carrier to a Phone modem would probably be legal, but
> a Data carrier not incidental, and completely separate from the Phone
> modem would essentially be operating a Data mode in the Phone/Image
> band. At least in the USA.
>
> An incidental carrier would have to be at the same symbol rate as the
> current modem though, is my thinking.

We go back to when will the US bring their regs in line with the rest of
the world? Again, holding us back. :)

--
73 de Tony VK3JED/VK3IRL
http://vkradio.com

[Steve]

Soon!

Since we already have failed as a Democracy (abdicated the Executive and Legislative branches), chaos will begin next week when China calls in their loans :-)

[K0OG]

Mel,

I presume you are referring to using the information field that scrolls across the bottom of the window?  If so, that's probably good enough.  Not a big deal, it just seemed like a good tool to have in the user interface.

Thanks all for your replies.

73,
-Joe-

[Remco Post]

Op 10 okt. 2013, om 09:41 heeft Steve <coupay...@gmail.com> het volgende geschreven:

I'm thinking the problem isn't technical, but legal. That is, an incidental Data carrier to a Phone modem would probably be legal, but a Data carrier not incidental, and completely separate from the Phone modem would essentially be operating a Data mode in the Phone/Image band. At least in the USA.

I don't know about the US, I do know about the Netherlands. Over here there is no LAW that prescribes which modes to use (with some exceptions, on a few bands only CW is allowed). Then there's the bandplan, which we radio amateurs choose to follow. So for more interesting modes... there's nothing stopping us from adding a bit of data...

An incidental carrier would have to be at the same symbol rate as the current modem though, is my thinking.

On Wednesday, October 9, 2013 7:38:33 PM UTC-5, Bruce Perens wrote:

On 10/09/2013 01:17 PM, Steve wrote:

Maybe add one more QPSK carrier to the program and send four bits at 50 baud (200 bps) in an additional 75 Hz BW @1.4 kHz total.

Well, I like the idea that PSK31 can be decoded with existing software.

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73, Remco

[Tony Langdon]

On 10/10/13 7:07 PM, Remco Post wrote:
> I don't know about the US, I do know about the Netherlands. Over here
> there is no LAW that prescribes which modes to use (with some
> exceptions, on a few bands only CW is allowed). Then there's the
> bandplan, which we radio amateurs choose to follow. So for more
> interesting modes... there's nothing stopping us from adding a bit of
> data...
>

Seems most of the world uses similar regulations. Here in Australia,
the main constraint is that the necessary bandwidth be less than 8 kHz
(for 160-12m), but as long as you stay within that limit, any mode can
be used. The US has a lot of weird, outdated band segments and mode
restrictions.

For completeness, the Australian band limits (for Advanced licensees) are:

2200, 630m - 2.1 kHz
160 - 12m - 8 kHz
10m - 16kHz
6m, 2m - 100 kHz
70cm and higher - entire amateur band (anyone for spread spectrum?).

The first entry is interesting in that if 2 stations manage to get a
_really_ good path between them on 2200 or 630m, they could legally work
each other using FreeDV. Down there, the technical constraints would be
the real challenge (i.e. getting an antenna to radiate efficiently
enough :) ).

[Bruce Perens]

Regarding US regulations, I think we can make a good case that a PSK carrier that is part of the same transmission is ancillary to the voice communication.

But this is an interesting case for me to add to my request to FCC.

It looks like the Republicans may be attempting to gracefully get out of the situation they created without losing face. Maybe we will have a working FCC again soon.

    Thanks

    Bruce

[Steve]

I just had a weird idea (maybe). Thinking of FEC for an added data channel, the first thing that comes to mind is a convolutional code, but then you get all that decoding overhead.

Since there's already Golay code, that would be a good way to add FEC to the data stream.  Four bits every 40 ms combined serially into 12 bits for a 120 ms delay (the horrors) before transmit. The BPSK pilot would sync the bit stream but not the 12 bit frame, so maybe a 12 bit special header frame sent every 20 frames (2.4 seconds) or 240 bits between frame sync.

That's 30 bytes FEC raw binary (or many more characters if using varicode) in 2.5 sec, or 12.5 bytes/sec if my arithmetic is any good.

73, Steve

[Matthew Pitts]

I'm not sure I follow; what is the real difference between using FreeDV (a DIGITAL mode) in the Phone sub-band and using PSK31 there, besides semantics? It's not like the Analog Phone folks are going to bother to care one way or the other if they do ever decide to take exception to people using FreeDV there.

I'll crawl back under my rock now.

Matthew Pitts
N8OHU

---

From: Steve <coupay...@gmail.com>
To: digita...@googlegroups.com
Sent: Thursday, October 10, 2013 3:41 AM

Subject: Re: [digitalvoice] Text "Chat" Function?

--

[Steve]

In the USA FreeDV is a Phone mode using a digital modem.  It's not a Digital mode.  PSK31 is a Digital mode using a digital modem.

As far as I can tell, the spectrum by mode occurred in 1954 or 1955.  An attempt was made in 2005 to change to spectrum by bandwidth, but it caused such a sucking sound that Katrina formed in the Atlantic and wiped-out New Orleans...  :-)

Here's one proposal from 2004:

http://www.qsl.net/kq6xa/freqplan/

[Matthew Pitts]

Steve,

Semantics; the payload is decoded differently, but the key is that they both use a digital modem. Why are we continuing to perpetuate the myth that the end decoded format dictates whether the mode is Phone or Data? Would PSK31 still be considered a digital mode if fldigi spoke the decoded output and you spoke into a microphone?

*crawls back under the rock*

Matthew Pitts
N8OHU

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Sent from my Android device with K-9 Mail. Please excuse my brevity.

[Tony Langdon]

On 11/10/13 12:55 PM, Steve wrote:
> In the USA FreeDV is a Phone mode using a digital modem. It's not a
> Digital mode. PSK31 is a Digital mode using a digital modem.
>
> As far as I can tell, the spectrum by mode occurred in 1954 or 1955.
> An attempt was made in 2005 to change to spectrum by bandwidth, but
> it caused such a sucking sound that Katrina formed in the Atlantic and
> wiped-out New Orleans... :-)
>
> Here's one proposal from 2004:
>
> http://www.qsl.net/kq6xa/freqplan/

Even that's overly complex by the standards in this part of the world,
though it's a vast improvement on what the US presently has. I always
get annoyed that the world can't play with something, because it's not
legal in the US (yet perfectly legal in many other countries).

[Steve]

One of the hazards, under the current system, is that you don't reach a point where Data and Phone are somehow combined. I don't know where that point is, and I certainly wouldn't ask any federal agency. First thing you learn in the military is never ask for permission.

An example of too much Data with the Phone, seems to be D-STAR, as they give it a "W" emissions designation (6K00F7W), as it uses both Phone and Data. At what point does an incidental Data become full-blown Data?  Obviously sending the callsign and maidenhead, or lat/lon would be considered incidental, but what about sending SMS messages? Maybe as long as it is less than 33.3% of the Phone data rate (pulling a rabbit out of a hat)...

Maybe if the FCC allowed "W" emissions in all amateur spectrum Phone bands - voila, fini !

73, Steve

[Tony Langdon]

The last sentence clearly shows a paradigm shift is needed in the US.
Whether D-STAR is a W emission or not is irrelevant in this part of the
world, as our regs don't distinguish. It shouldn't be a question of
whether the FCC allow a specific type of emission, but rather question
why they should care at all, provided (1) they can decode it if needed
(e.g. through readily available software/hardware), and you're following
the regulations with regards to content, spurious emissions, bandwidth,
frequency, etc.

[jdow]

One more question to underpin yours. Where in the FCC rules does it say
I must run only one transmitter using only one mode at any given time?

Since there is no signal difference between combining two transmitters
on the same frequency on the same channel using different modes and
using one transmitter with two different modes simultaneously this
should be a slam dunk.

{^_^} Joanne/W6MKU

On 2013/10/10 16:01, Matthew Pitts wrote:
> I'm not sure I follow; what is the real difference between using FreeDV (a
> DIGITAL mode) in the Phone sub-band and using PSK31 there, besides semantics?
> It's not like the Analog Phone folks are going to bother to care one way or the
> other if they do ever decide to take exception to people using FreeDV there.
>
> I'll crawl back under my rock now.
>
> Matthew Pitts
> N8OHU
>
>

> --------------------------------------------------------------------------------
> *From:* Steve <coupay...@gmail.com>
> *To:* digita...@googlegroups.com
> *Sent:* Thursday, October 10, 2013 3:41 AM
> *Subject:* Re: [digitalvoice] Text "Chat" Function?

[jdow]

Bonnie was way too sensible for born regulators and nannies. It would have
rendered their jobs obsolete. (You see the difference between other countries
and our real situation and wonder which government really is more in the
hair, faces, and of late bathrooms of its citizens. And now we have King
George in the White House.)

{^_^} Joanne/W6MKU

[Tony Langdon]

On 11/10/13 4:00 PM, jdow wrote:
> Bonnie was way too sensible for born regulators and nannies. It would
> have
> rendered their jobs obsolete. (You see the difference between other
> countries
> and our real situation and wonder which government really is more in the
> hair, faces, and of late bathrooms of its citizens. And now we have King
> George in the White House.)

And here I am saying Bonnie's proposal was actually _too_ conservative!
(i.e. didn't go far enough). :) It still has legally segregated band
segments (by bandwidth instead of mode), something we don't have under
our new regs (i.e. since 2005). Carving up the bands is best left to
the amateurs through band plans, because these can be changes quickly to
suit actual band usage. Our band plans have changed several times since
the regulations were changed to remove all references to specific
modes. These days, seems there's a new band plan out every 6-12
months. The regulators can't work at that pace! :)

[jdow]

Agreed. But, sadly, the serfs of the United States of America have seen
fit to allow ourselves to be saddled with ridiculous regulations. And
all too much of it is due to the #WR$E_( that refuses to just die.

{O.O}

[Bruce Perens]

The regulators didn't have any problem with Bonnie's bandplan. ARRL's membership forced them to withdraw the request for rule-making.

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Sent from my Android phone with K-9 Mail. Please excuse my brevity.

[Tony Langdon]

On 11/10/13 5:05 PM, Bruce Perens wrote:
> The regulators didn't have any problem with Bonnie's bandplan. ARRL's
> membership forced them to withdraw the request for rule-making.

The ARRL really needs to take a look at itself then. As I said in a
previous message, I consider Bonnie's bandplan good, though still rather
conservative.

[Matthew Pitts]

That's because most of the people making the regulations aren't technically sophisticated enough to understand that there is no difference at the RF level between digital voice and digital data, which is where it counts, in my opinion. The current US regulations seem to be holding onto the illusion of a difference between them based on how we interact with the equipment used.

Matthew Pitts
N8OHU

[n8vnr]

I too am finding some purpose vs protocol semantics somewhat perplexing.

Let us take for example EasyPal. It is an adaptation of WinDRM (a voice modem) to send JPEG2000 files (ostensibly data) which are images. I hear this mode operated in the phone/image part of 20m, just above traditional SSTV on 14.233, due to the latter part of that sentence. Since it's digital, it doesn't sound all that dissimilar from FreeDV on 14.236 to the uninitiated.

Another example: MFSK16 image. An add-on to a text chat mode that more closely resembles traditional SSTV in that it is analog. I just had a QSO with a station in Tennessee where we were chatting in the digital part of the band and swapping pictures as part of that conversation. Because we switched from digital text to image and back, did we inadvertently break regs?

Not sure I have a point one way or the other. Just some real world folly.

73 de Kevin N8VNR

[ric5]

Great point Kevin!

Rick Kd4jrx ALE Today

From: n8vnr

Sent: Friday, October 11, 2013 10:42 AM

To: digita...@googlegroups.com

Subject: Re: [digitalvoice] Text "Chat" Function?

--

[Bruce Perens]

On 10/11/2013 12:05 AM, Tony Langdon wrote:

The ARRL really needs to take a look at itself then.

I didn't say it was ARRL's problem. ARRL's _membership_ made them withdraw the request for rule-making. So, the problem is really in the general population of Radio Amateurs here in the States.

[siegfried jackstien]

... with easypal you can send any kind of data

So ... when I send a picture it is a picture mode ... when I send an mp3
file with my voice it is a voice mode and when sending text it is a text
mode?!?!?!?!?!?!?

Any way to make it more complicated?!?

Dg9bfc

sigi

> -----Ursprüngliche Nachricht-----
> Von: digita...@googlegroups.com [mailto:digita...@googlegroups.com]
> Im Auftrag von Matthew Pitts
> Gesendet: Freitag, 11. Oktober 2013 14:00
> An: digita...@googlegroups.com
> Betreff: Re: [digitalvoice] Text "Chat" Function?

[Matthew Pitts]

Ah, but how much of the ARRL's membership was it that was responsible for it? It's just like anything else; if the real majority doesn't say anything, a very vocal minority can seem to be more representative of an organization's members than it actually is.

Matthew Pitts
N8OHU

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