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 abo
>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.
The signals are sinusoids none the less, but maybe FMing a base band square
wave would do the trick. This would in effect be F
>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
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
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 discu
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
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
--- 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
> > mode
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
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 advers
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 VK2
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 ban
Hi John,
I like an ALE for starters with DBM ARQ chaser... hi hi
I have just had a long QSO after an AQC-ALE link (this is the latest
ALE that is only found in state of the ar Military rigs) where I was
sending DBM ARQ and get my handshakes and the other station was
sending AMD Orderwire and
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?
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
Do you suppose that what happens is that when a new mode comes out a lot
of us want to try it and then after some experience, make a decision
about its efficaciousness ... or not? And then may revert back to the
mode or modes that we do find work best for us?
For the bandwidth, I still like MFS
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.
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
-Ori
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
===
> 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
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
Actually I think that MT63 would actually work well. While it may not be the
most robust mode, and during a hurricane if you are "in the storm" your noise
level is quite high...I've see 20-30 over S9 more than once so not matter the
mode, most likely you will be QRO. The 10-15 watts output of
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, rain/thunder
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
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 ARQ
--- 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
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
-Original Message-
From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED]
Sent: Tuesday, September 19, 2006 7:15 PM
To: di
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
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 A&M Univ in their weather labs that
are also computer experts and digital data e
Bill,
In the past the HF communications between the NWS offices via amateur radio has
been voice because there was not a reliable data mode available to them. In
exercises they have tried PSK31 but were not satisfied with the results. They
have not tried MT63 thus far. I because none of the
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.
Fo
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
That kind of doubt should always be the first
consideration in data transmission.
Some 9 years ago I had a request for a project that
never materialized, because the "client" wanted to
transmit several raw, uncompressed data base files to
a central office, subtituting a "floppy mail"
transfer, a
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
h
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