I finally got around to installing WSJT-X. I haven't even read the manual,
but it's decoding JT65 (and maybe JT9) signals on 160 and displaying
callsigns just fine. You don't even have to tune the signals in, they just
have to be in the passband. The software does it all for you.
There are many
On 1/28/2014 12:32 PM, Mike Waters wrote:
If you see hum from a ground loop, then simply isolate the
audio line using an audio transformer from an old 56k modem.
No transformer is necessary. Simply bond from chassis to chassis of all
the interconnected equipment, and, if possible, get power
No transformer is necessary. Simply bond from chassis to chassis of all
the interconnected equipment, and, if possible, get power for all of it
from the same AC outlet.
That doesn't always work, Jim. As a matter of fact it is a generally bad
idea, because if a connection develops any
I have an idea, it may be far fetched, but I think a good one none the
less. As a group we can create a document, in short explaining the issues
that are hand , that the technical people will see and understand the
non-technical end users ( not saying all end-users are non-technical ) will
also
: Topband: Digital mode spurious issues Ideas for possible
resolution
I have an idea, it may be far fetched, but I think a good one none the
less. As a group we can create a document, in short explaining the issues
that are hand , that the technical people will see and understand the
non
I know for the year or so I was very active on TB JT65, that I
never once EVER ( I am an east coast station aswell ) worked a single
station In Europe, or any other DX excluding Canada. Not even Mexico on
JT65 or any other 'digital mode'. I truly believe that the dream of regular
DX
I hit enter by mistake, but that sum's it up from my perspective.
-Steve Raas
N2JDQ
On Thu, Jan 2, 2014 at 6:00 PM, Steven Raas sjr...@gmail.com wrote:
I know for the year or so I was very active on TB JT65, that
I never once EVER ( I am an east coast station aswell ) worked a
Well, I certainly have to agree, Tom, if the signal on the desired
sideband
is just a single shifting tone. Might get messier if an sudio stage or A/D
is driven into limiting and producing harmonic distortion at audio, I
guess.
The entire thing for digital modes was poorly planned. I'm
On 12/31/2013 7:13 AM, Tom W8JI wrote:
Collins got burned by this. They tried running a pure audio tone into
the SSB transmitter of the early S line to generate CW. The FCC (back
How is this different than RTTY using the AFSK method?
In my FT-1000D, if you try to use FSK mode for RTTY it
It's really not any different. The question is whether the levels and
output are engineered clean, and KEPT that way. That can be done
completely internally to a TRX and maintained. But when the (audio
baseband) signal is generated external to the radio then all of the issues
of
On 12/30/2013 7:55 PM, Tom W8JI wrote:
IMD **requires** two or more signals at once, and does not appear
anything like sideband leakage.
Actually, IMD can be produced by ANY keying waveform -- for example, the
envelope of a CW or RTTY signal. To understand this, think of the
keying
Actually, IMD can be produced by ANY keying waveform -- for example, the
envelope of a CW or RTTY signal.
Let's not divert the issue.
A rise and fall is always composed of many frequencies making up sidebands,
otherwise it would have no shaping. Even CW is an AM signal, when we look at
rise
How is this different than RTTY using the AFSK method?
In my FT-1000D, if you try to use FSK mode for RTTY it
turns out that the rig is still running AFSK, using
an internal audio source.
I've never looked at the FT1000, but I doubt that is a clean system. It
would still be like a SSB
On 12/31/2013 11:15 AM, Tom W8JI wrote:
We are not talking about momentary sidebands generated during level
transitions. We are talking about spurious signals up and down the band.
You may be, but I am talking about the larger picture.
73, Jim K9YC
_
Topband Reflector
As utterly simple as it is to shift a VFO, it's almost hard to believe that
any major manufacturer would do it with audio.
When I was heavily into HF RTTY software development years ago, it was a
trivial thing to FSK my Collins 32S-3's VFO. I just connected one pin of
the RS-232 port through a
On 12/31/2013 11:21 AM, Tom W8JI wrote:
I've never looked at the FT1000, but I doubt that is a clean system. It
would still be like a SSB transmitter with audio signals if that is how
they do it. It would be much better to actually shift a carrier, and not
do the baseband audio signal run
On Tue, Dec 31, 2013 at 2:21 PM, Tom W8JI w...@w8ji.com wrote:
. It would be much better to actually shift a carrier, and not do the
baseband audio signal run though a balanced modulator and then through a
sideband filter.
Better yet to generate the best transition waveform in data (far more
)
--
Message: 1
Date: Mon, 30 Dec 2013 12:11:49 -0500
From: Tom W8JI w...@w8ji.com
To: Topband topband@contesting.com
Subject: Topband: Digital mode spurious issues
Message-ID: AB0B5258E3B345428ADE0FAFD65179C0@MAIN
Content-Type: text/plain; format=flowed; charset=iso-8859-1;
reply-type=response
I have
An interesting point from Tom re SSB modulation added problems.
A really informative website re plain old RTTY is
http://www.frontiernet.net/~aflowers/k3rtty/k3rtty.html
and is a good introduction to the technical complexity of digital
modulation systems and what to do to make better RTTY
AFAIK, all non-DSP rigs with synthesizers work this way.
Assuming you want the output frequency to be derived
from the master clock frequency, there is no easy
way to shift an RF carrier. You can't use a free
running oscillator, because it won't be derived
from the master clock frequency. You
I have not been on the air for a year or so, but decided to get back on. I
was listening to a DX station around 1833 when a digimode station up roughly
around 1837 came on with a LSB spurious signal on 1833. His signal was a
series of slowly changing stepped tones. I don't know what mode that
Tom,
I believe the mode that operates at 1873-1838 is JT65, and WSJT is needed
to decode it. I never tried it. It was developed by K1JT for weak-signal
and EME work.
http://www.physics.princeton.edu/pulsar/K1JT/wsjt.html
A common scenario with digital modes is that the audio into the mic input
You're both right -- it is either JT65 or JT9. WSJT software, based on
protocols developed by K1JT, will decode both modes. Another software
package called JT65-HF will decode only JT65.
And yes, the trash Tom was hearing was either overdriven audio or a
crummy radio or both. Some of the
Does the Joe Taylor software have a provision for this?
No, Joe Taylor's protocols are not capable of operating in LSB.
73,
... Joe, W4TV
On 12/30/2013 5:59 PM, Richard (Rick) Karlquist wrote:
The simplest technical solution would be for the
digital mode users to put the radio in LSB
This is a little off-topic relative to the Subject line, but extremely relevant
to enjoyable Topband operating:
On Dec 30, 2013, at 6:51 38PM, Jim Brown j...@audiosystemsgroup.com wrote:
Fast rise time of the keying waveform is the major cause of clicks. W8JI and
others long ago identified
You are right. There is no universal software that can do that. But I used
to code software, and I'm convinced that the status quo in amateur digital
software can be greatly improved. See
http://www.eham.net/ehamforum/smf/index.php?topic=80740.0 .
If anyone wants to take up where we left off on
, K4OTV
-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Jim Brown
Sent: Monday, December 30, 2013 6:52 PM
To: topband@contesting.com
Subject: Re: Topband: Digital mode spurious issues
On 12/30/2013 3:13 PM, Charlie Cunningham wrote:
I would think that IMD
KHz almost 100KHz up and down 1838. This is a growing problem.
73, JC
N4IS
-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Mike
Waters
Sent: Monday, December 30, 2013 1:31 PM
To: Tom W8JI
Cc: Topband
Subject: Re: Topband: Digital mode spurious issues
[mailto:topband-boun...@contesting.com] On Behalf Of Tom W8JI
Sent: Monday, December 30, 2013 10:56 PM
To: topband@contesting.com
Subject: Re: Topband: Digital mode spurious issues
Thanks everyone for the suggestions. I'm going to have to install some
software to identify some of the signals.
I would
Tom,
I would have to agree. Let me also add my personal experiences on 160m
JT65, were good, however, at the latter stages of me being QRV on the band,
I was very politely spoken to, and delightfully educated on such matters by
Les, KL7J , whom really gave me some great insight on a then and
Maybe not.
I got a private e-mail earlier (which I haven't had time to respond to yet)
that stated To see who is QRV on 160M WSPR at any given time, check at
http://wsprnet.org/drupal/wsprnet/activity
Scroll down to 160M and the stations are listed (those followed by an R are
just receiving).
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