[Elecraft] K3/K3s; Digital modes, specifically DV

[Matthew Cook]

I'd wait until David VK5DGR gets the FreeDV bit rate lower which will
improve the Eb/n0 requirements and bring the performance closer to that of
SSB.  If you're not already following along on David's blog it's worth a
read (http://www.rowetel.com/) his writing style is easy going and he
explains things well.

His current work on Codec2 700C surpassing MELP 600 in performance along
with some new modem ideas will push the limits of what's possible with
Digital voice on HF.  It will not be long and the performance of FreeDV
will be equal too if not surpass SSB on a standard HF channel.  Yes this
can be done already, however you do end up sounding like donald duck and a
bit robotic for my liking on current technology.  The work on Codec2 will
change this.

While the FreeDV code base (Modem + Codec2) is open source the integration
work is not insignificant.  The current FreeDV codebase in the SM1000 runs
on a STM32V405xxx 32-bit ARM core clocked at 168MHz with a real FPU and no
RTOS it runs bare metal.  That is some serious beans in terms of DSP
processing !!!  The effort involved in bringing this into any product
should not be underestimated, there is still some very serious work to do
which results in $$$ spent.

While FreeDV is under active development interfacing a linux based laptop
to the K3 and using this to keep up with the Jones's is perhaps the best
course of action.  Those with the K3s are already ahead of those with a
stock K3 since they already have the internal USB sound card.  However
making cables for laptops and PTT cct's isn't hard either.

Once the performance of FreeDV surpasses that of standard SSB then would it
be time for internal integration work to begin.  I'm fingers crossed that
the processors and DSP in the next iteration of the K-line will have enough
processing beans to "answer the meaning of life the universe and
everything" in real time.  As David tells me on the local repeater most
mornings "MIPS are cheap".  That is about the time frame I'd expect both of
these technologies to collide.

YMMV.

73

Matthew
VK5ZM

On 28 March 2017 at 04:40, Richard Fjeld <rpfjeld at outlook.com> wrote:

> Greetings to all,
>
> The K3/K3s is an excellent radio for digital modes due to the ease of
> interfacing with a computer if desired.  A computer is not even needed
> for some digital modes, and I have tried that successfully.
>
> I have mentioned in the past that I had tried the free software for
> digital voice on HF called 'FreeDV'.  I had worked a Canadian ham a few
> times using it and he has been keeping in contact with me via email
> encouraging me to get back into it.  I am starting to get up to date
> again, and I found accurate reviews of it on
> http://www.eham.net/reviews/detail/11016   by K2RWF and WA0TPN.  I think
> you will find the reviews interesting and informative.
>
> Notice that the reviews seem to be either at, or near, 5/5 or 0/5. I
> think both of the reviews I mentioned answer why that is.  I will keep
> my experience mute and let you glean aye/nay from the reviews. Whether
> you approve of digital voice or not, the K3/K3s is a natural for using
> it, and it's fun.  (As always with digital modes, be kind to your finals.)
>
> FYI,
> Dick, n0ce
>
>
> --
>
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