I always set these software-based goals before the test, but funny how they get
delayed in the face of driving kids around to acitivities and stringing up
antennas in the trees, and then when the sun goes down and the contest starts
swinging, all those pie in the sky virtual dreams evaporate in
I thought I'd share some data points from my Stew Perry log. Even though
propagation to the west coast seemed good from upstate NY, I had the
impression of less activity than expected from California so I looked
closer at my log. What I found was 13 q's from California and 14 q's each
from neighbo
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 surpr
W8JI said:
.as did KW with their KW2000 over here.
Tom G3OLB
_
Topband Reflector Archives - http://www.contesting.com/_topband
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
tur
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 off-level-for-op
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 envelope
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 transmit
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 Archives
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 res
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 though
On Tue, Dec 31, 2013 at 2:21 PM, Tom W8JI 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
difficult
- Original Message -
From:
To:
Sent: Tuesday, December 31, 2013 12:00 PM
Subject: Topband Digest, Vol 132, Issue 30
Send Topband mailing list submissions to
topband@contesting.com
To subscribe or unsubscribe via the World Wide Web, visit
http://lists.contesting.com/mailman/listinf
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 si
I don’t am still puzzled why the digital modes decided to use the 1837 to 1839
area with the size of the 160 M band. I know the SSB guys use a lot of the
1840-1900 area but 1900 to 2000 is usable isn’t it? I rarely hear much up
there and 3 or 4 khz up there would never be missed. Probably not
On 12/31/2013 5:10 PM, Mike Greenway wrote:
> I don’t am still puzzled why the digital modes decided to use the
> 1837to 1839 area with the size of the 160 M band.
For the same reason the SSB guys insist on using 1840-1850 ...
with their significantly smaller band (1810-1850 in some cases)
Regio
Absolutely! From what I see from my QTH in SW MO, 1845 would be a good
place for JT65 to move to. There is a ragchew group that meets on 1850, but
seldom is there much activity below that.
I seldom listen much above 1900. Maybe you're right, that would be a better
place. But they definitely need t
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 ca
19 matches
Mail list logo
