Rick,
Yes I had trouble printing 100% of what Mac WN3C was transmitting during
the inital 8/500 contact, we did go to 16/500 and the print came back to
90%.
After discussing the settings with Mac it became apparent that there was
several issues that was causing problems on Mac's end. The amou
Although I am not an engineer, my understanding is that group delay is
the phase shifting signals experience as they go through circuits such
as filters. A non linear response as you go across the filter bandwidth
means that different tones will be affected differently and cause
smearing of the
At 06:41 AM 9/21/2006, you wrote:
>Rick,
>
>Please explain "group delays". I am unfamilar with that term in
>reference to transmitting equipment.
>
>Walt/K5YFW
I am not Rick, but you can find the definition here:
http://en.wikipedia.org/wiki/Group_delay
Regards,
Chuck AA5J
Need a Digital m
Rick,
Please explain "group delays". I am unfamilar with that term in reference to
transmitting equipment.
Walt/K5YFW
-Original Message-
From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED]
Sent: Wednesday, September 20, 2006 4:28 PM
[stuff deleted]
Another thing that I came
Hi gang.
The whole group delay fuss is pointless in my opinion because of the
constraints that are put on the operating modes by our lovely ionosphere. I do
not think that group delay is an issue at 100Bd symbol speed.
The flattness of the passband is more an issue but it is something that the
As Doug Smith has pointed out, the group delay issue on amateur gear can
be challenging, even with training. The ionosphere is very unforgiving.
Any tests you can do would be great. Have you considered discussing this
with the Digital Voice Working Group at ARRL? They have gone through
quite a
Rick,
Yes group delay is an issue, but with adaptive training this too can be
overcome. Sound cards, or external modems using DSP or preferably FPGA's
would be a fine compliment to most amateur gear. The SDR (software defined
radio) that Jose mentioned will be the best solution going forward
Jim and group,
Any modems that are used for amateur radio, hardware or software,
generally would need to be compatible with the kind of equipment that we
use in order to enjoy wide adoption. It is true that some ham equipment
will not work well with modes that require fairly stable frequencies.
Jose,
I think you are correct. SDR allows you to make the radio for whatever
type of modulation/protocol you want to send. As you say, if that
modulation/protocol changes, just change the firmware. I think that this
will be the next homebrew revolution. FPGA's are getting very cheap and
ea
I think it is not the only solution needed. A wider
radio might be needed too (rules allowing, that is).
So far, I see a Software Defined Radio as the
solution.
You may, then, define the bandwidth you NEED on the
fly.
In the cell phone business, the operators see SDR as
the solution, because it
--- jgorman01 <[EMAIL PROTECTED]> wrote:
> I've been reading all the posts over the last
> several weeks about
> single tone/multi-tone, baud/bps, narrow/wide, etc.
> digital
> modes/modems. The one thing I see missing is any
> discussion of the
> actual RADIO's being used in these systems
Spot on.
What about desgining and building a "QRP" radio for digital use.
Its seems to me that some of the problems you mention are because the radio
is made for many modes. What if the radio was just build for RTTY, PACKET,
PSK31, PACTOR, etc?
Instead of a 300-3500Hz audio bandwidth, it could
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