Some Tips On Using WSJT/JT44
Most 144mhz skeds are being run on 144.150-144.170mhz
1. Be sure you PC clock is set to WWV within 1 second or
less.
Note - It is possible to get only 1 way copy if one the
stations PC clock is too far off from WWV.
Note - your PC Clock should be set
to local time. Set your WSJT software
SETUP/OPTIONS
UTC offset amount
there to get correct moon data for JT44 mode.
2. Be sure your receive noise level is set to 0db.
3. Look for software Sync by observing
the DT field. For an EME signal
you should see
a DT = +2.5 or close to
it. For tropo Sync your DT field should show
DT =
+0 < /FONT
> . These are
approx. values and they
can vary some.
4. Keep an eye on the RED line.
That is where you should see a peak to show a received
signal
.
If you see
a peak in red line take a look at the DT field to see if you got program sync on
that signal.
5. Since WSJT/JT44 can scan + -
600hz on 144mhz
you do not need to worry about the doppler
offset
as
much. 144mhz doppler should be less than 600hz in
most instances
. On higher frequences this is
not
the case. The higher in freq. you go
(such as 432mhz) the more important it is to use your RIT
to compensate
for
doppler. 432mhz doppler can easily exceed 1mhz.
6. Use the INCLUDE/EXCLUDE during a
RECEIVE sequence
to include the last decode or exclude the last
decode from the
bottom message average box. This is handy to keep a garbage decode from messing
up the
information in the message average decoded
box.
7. Most signals will start to decode at
a level of about -25db approx. You should get
good decode at levels around
-18db or better . This is
about -10db below what you could detect if using cw mode.
8. Only pay much attention to the
DF (difference in freq) if you see a good DT and see
a good peak on Red Line
.
You can get all
sorts false DF readings when you do not actually have software
sync.
9. If you do not have elevation control
most yagi's will only work from about +2deg to
+15deg
of moon. Expect to
have best results when your moon is in the 5-10 deg range
.
10. Due to Spatial and Faraday
rotation there is a real advantage to using X-Pol
type yagi's
so that you can xmit
on one
polarity and receive on another. Faraday rotation can take a HZ signal and
rotate it at times to a VERT signal.
That can give you up to 20db of loss on
the receive signal if you are not able to compensate by changing your
receive
polarity. Faraday rotation is caused by the ionospere and
the amount of faraday changes all the time. There are good
days and there are bad days when it comes to faraday
rotation.
11. Most EME skeds are run using standared EME format. There is an advantage though to
using standard JT44
Non-EME format since it requires one less sequence
(starts off with BC+Report instead of just
BC in EME format).
If you have a very limited EME moon window (due to not
haveing elevation control) you might consider this.
BC+Report+R is a valid
contact no matter which format is used. If you wish to try it this way it for
sure would be
a good idea to clear it with your sked partner
1st.