Updated at: 28-12-2005 (12:30).
ISS cross-band repeater
(doppler).
READ!!!!! BEFORE YOU OPERATE!!!!!!!!!!!!!!!!!!!!!!
Listen
here the audio recording of ISS repeater QSO's above USA
There are a few things what you should know to operate
the ISS repeater.
Do not use too loud microphone modulation otherwise
the repeater goes off for a
few moments.
Many stations do not correct their fequency with the doppler
effect that's the reason you hear often much QRM.
If you do not correct your doppler please STOP operating
on the ISS cross-band repeater!!!
The ISS is traveling with an speed of 7km per second.
When the ISS is comming to you the RF signals (from
the ISS) will be pushed (it means the ISS freq. will be increase).
When the ISS is leaveing, the ISS RF signals will be pulled it
means the ISS frequency will be decrease, this is
what we call doppler effect.
A good example of doppler effect is a raceing motor-cycle.
When it comes to you (with high speed) the sound is high, and when it is
leaving the sound is low.
Example: 10 Minutes (high elevation pass).
You can see the
doppler effect is 3 times more on 70cm in -
comparing with the 2 meter band!!!!
Example: 5 Minutes (low elevation pass).
If you compare the 5 minutes
pass to the 10 minutes pass
you will see that the 5 minutes pass requeres less frequency
correction.
When there is a short 1 minute (low elevation) pass, I do not
change the frequencies!
Do you have a transceiver
(ts-790, ts-2000, ft-847...) with -
a MAIN and SUB frequency display?
You can display 437Mhz on the MAIN-display, and
145Mhz on the SUB-display.
Turn the audio off at the MAIN unit, and turn it on at the
SUB unit (do not use the squelch!).
Use a headphone so you can concentrate much better at
weak signals in the noise.
During the ISS pass you have to jump a few times to your SUB
display to correct 145Mhz receiving frequency.
When your transceiver can not make 1 Khz steps on the FM mode,
you can select the 5 Khz steps (DO NOT USE 10 or 12,5Khz
steps!!!).
For some simple transceivers it is better to program several
doppler frequencies in the memorie channels.
When you have two single band transceivers one for 2m. and
one for 70cm it is easy to tune each transceiver separate!
Always
operate full duplex so
you can listen direct on
the ISS downlink frequency (even when you are TX'ing!).
Keep tunning your TX-VFO button (watch at your tracking
software).
If you have a tranceiver with CAT interface it is possible
to correct the doppler automaticly with your computer (-:
Nice freeware software is Hamradio De Luxe:
http://www.hb9drv.ch/
Even when you do not have a computer-controlled rig
it
is recommed to take a look at Hamradio De Luxe so you can see
the doppler frequencies (chanceing!!!) on your screen, so you can
adjust your transceiver manualy (with your hand).
ISS repeater doppler frequencies (easy software for all!).
Hello All,
There
are several software programs which can
tell you the ISS doppler frequencies, even
without an rig controlled (CAT) transceiver!!!!
For example Hamradio De Luxe (freeware).
LOOK HERE FOR A
SCREENSHOT!!!!!!! <-------------------Click on
the link!!!!!!!!!!!!!
Download Hamradio De Luxe
Download
here Hamradio De Luxe v3.2 (7,5mb)..
Run
the setup file and install.
Start the Hamradio De Luxe software and
go to the menu (above):
Tools---->Satellite Tracker (maximize the window!).
Click (above) on the Satellites button.
Now you see 2 windows (on the left), drag the
ISS from the left window to the right window.
Click on the download button (under)be sure
you are connected to internet cause now the
HRD software download keppler data!
Click on observer, enter your locator and
convert (or if you want direct lat&long).
Click on the Ground Control button:
VFO
TX: v (select!).
RX: v (select!).
Satellite
437.800.000
145.800.000
On
the right window you see the ISS doppler
frequencies!!!!
Now you can adjust your transceiver(s) -
manualy (by hand) or automatic (CAT).
Even when you do not have a transceiver with
1Khz steps, you can select your transceiver
at 5khz steps (do NOT use 10khz steps or more!).
Please use a full-duplex (or 2) transceiver(s) so
you can listen all the time to the RX downlink
even when you TX!!!!!!
TIP!!! Print this story on paper.
When
you have questions let me know in
the issfanclub forum!!!
73's Cor PD0RKC
remember
this story have copyrights, keep
it on IFC (or here!) so I can update (or correct).
Please read my copyright details!!!!!!!!!!
