WinDRM - HF Digital Radio Mondiale
http://n1su.com/windrm/ WinDRM is a digital mode on HF that lets you do
digital voice, image and data. You can transfer data at almost 1KB/s
without using proprietary hardware!
SDR1000 http://www.flex-radio.com/ is a product of FlexRadio Systems and is
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. Kind of funny in a
digital RADIO forum populated by
I have talked to some scientist at a large research independent facility who
are doing HF modem research for the government. Here is some of what they
believe...
For a broadcast mode, use heavy FEC. If the receiving stations have transmit
capability, let them NAK missed data periodically.
You are right Erik...the problem is that all NWS offices are using the same
equipment and same forecasting models, computer programs and all require
specific information.
There are a couple of hams working at Texas AM Univ in their weather labs that
are also computer experts and digital data
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
--- 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. Kind
Packet COULD have been a solution, but had a
modulation format unable to do the job.
As a MultiPSK user, I think that PSK31 is inadequate,
maybe PSKFEC could perform better, but I would try
PAX.
It has some long keying delays I don't like from the
moment you press the ENTER key, but is an
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
Where did everyone go that used to be on Chip64, DominoEX, MFSK16?
There is a little Olivia, but seems to be a lot less users than when
it was released for Multipsk and MixW. I know there was a DominoEX
contest about a month ago, but was not able to participate due to
crummy weather,
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
Actually TAPR and some other groups have looked at this EVM but the
disinterest by hams in earlier EVM projects caused them to drop
experimentation.
Walt/K5YFW
Times they are a changin' ... perhaps it would
make sense to take a new look?
--
Thanks! 73,
doc, KD4E
... somewhere in FL
URL:
greetings:
Today I receive the message below telling us that the Greece PSK31 Team is
gearing up to challenge any other team(s) in the upcoming TARA PSK Rumble. This
is really good news and I sure hope we'll hear from some other teams that
wish to challenge them.
73 de NY2U Bill
Yes...I think that if hams working HF digital can ever come up with some
specifications on what is needed/wanted in a high speed, robust HF mode (modem)
TAPR might take on the project. But they will not (and should not) start a
project with no goals or end product in mind.
Walt/K5YFW
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
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
There are still a lot of us on OLIVIA and MFSK , both on 40and 20. Had a great
chat with Txema in Spain on 20 this past weekend
Think a lot of folks on here have consumed too much ALE, and forgotten about
using these modes :}
Would like to try a DominoEX and PAX2 QSO sometime. You up for that?
It seems apparent that the narrow-bandwidth modes that are very visible on
the waterfall
such as PSK31 and CW are the modes that people use - mainly because they
are easy to find visually. Designers of new modes should keep this in mind.
Also to be kept in mind is the approx 2.4 KHz SSB filter
Brett,
Try gmfsk or the new cousin fldig if you want a free multi-mode digital
program that does CW.
Showing mode info in pix on the waterfall is also a nice trick, one I
hope to see in these programs somedsy. I believe MixW has it.
Leigh/WA5ZNU
On Wed, 20 Sep 2006 4:55 pm, Brett Owen Rees
Even a QRP rig for digital use only will have these same problems
that have to be examined and subsystems properly designed and built.
A 'simple' audio amp in a tranceiver may work fine for SSB voice,
but may have amplitude and phase variations over the designed
bandwidth that can
Brett try Multipsk's CW and CCW.
Andy K3UK
On 9/20/06, Brett Owen Rees VK2TMG [EMAIL PROTECTED] wrote:
It seems apparent that the narrow-bandwidth modes that are very visible on
the waterfall
such as PSK31 and CW are the modes that people use - mainly because I have
been
--- In digitalradio@yahoogroups.com, Jose Amador [EMAIL PROTECTED] wrote:
--- 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
Until you have affordable DSP's that can output substantial RF power
at frequencies between 1.8 mHz and 30 mHz, analog devices will still
be needed to translate and amplify the SDR generated signals.
Consequently, you will still have the issues I have mentioned to
deal with.
Jim
WA0LYK
Yes, you're almost dead one what I was trying to say. You just
can't ignore such an important part of the system by just assuming
that the RADIO (any ham radio) will perform in the manner you wish.
What are the requirements for a RADIO to optimally handle the modem
signals being
I'm not sure you can simply use a frequency generator. Remember,
what we are talking about are in essence, pulses, that is tone
pulses throughout the audio passband.
Perhaps one could use a pulse generator with a one, or ten, or 100
millisecond pulse at every 100 Hz from 300 to 3000 Hz at
I guess my point is, do you know what your passband is in your
radio. Are the 3 db points really at 300 and 2700 Hz? Are there
any fluctuations at other frequencies in the passband? What about
phase variances throughout the passband?
I have made measurements on my IC-746. I set the RX filter to
I have noticed that my tx power varies depending upon where I am in the
passband.
As my radio most likely uses the same crystal filter for tx ssb generation
as it does for RX filtering
then one can in a way map the response of the filter. My radio is an Alinco
DX-77, and I get maximum
output at
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