[sarex] ISS in repeater mode

["Scott H. Stevens / N3ASA" <n3asa@xxxxxxxxx>]

Hi folks,

Kenneth Ransom reports that the ISS is currently in 
crossband repeat mode.  Enjoy!


THe following information may be helpful in using this 
mode.  It's supplied by Charlie Sufana, AJ9N:

ISS frequencies:
Remember that the ISS radios are not able to correct for 
Doppler as the frequencies are channelized. So it is up to 
the ground station to do the Doppler correction. For 2 
meters, the Doppler is about +3kHz at the beginning and 
goes to about -3kHz at the end. For 70 cm, the Doppler is 
about +10kHz at the beginning and goes to about -10kHz at 
the end. The 70cm Doppler is roughly 3 times the 2m 
Doppler. Many of the tracking programs have the ability to 
calculate the Doppler.

Also recall that the frequencies are:

Crossband voice mode (437.80 MHz up, 145.80 MHz down)
Public packet mode (145.990 MHz up, 145.80 MHz down), 
Public voice mode (145.20 MHz up for Region 1; 144.49 MHz 
up for Regions 2 and 3; 145.80 MHz down for all regions)
School contact mode (xx up and 145.80 MHz down)

These are the frequencies that are at the ISS. So you will 
have to do the Doppler correction on the ground so that at 
the ISS the resultant frequency is that listed above. For 
example, if you are on the public voice mode in Region 2 
and the Doppler is about +2kHZ, then you would transmit up 
on 144.488 MHz and listen on 145.802 MHz. The ISS is not a 
transponder like the rest of the OSCAR sats.

The table below may be used as a guide for setting up your 
radio.

Memory   Memory    2m      Ground  Packet  Region 1 Region 
Crossband 70cm
location location  Doppler station uplink  1        2/3 
   repeater  Doppler
if 5 kHz if 5 kHz  in kHz  listens MHz     uplink   uplink 
uplink    in kHz
steps    steps             at MHz          MHZ      MHz 
   MHz

1                  5       145.805 145.985 145.195 144.485 
437.785  15.014
          1         3       145.803 145.987 145.197 
144.487 437.791  9.008
          2         2       145.802 145.988 145.198 
144.488 437.794  6.005
          3         1       145.801 145.989 145.199 
144.489 437.797  3.003
2        4         0       145.800 145.990 145.200 144.490 
437.800  0.000
          5         -1      145.799 145.991 145.201 
144.491 437.803  -3.003
          6         -2      145.802 145.992 145.202 
144.492 437.794  -6.005
          7         -3      145.797 145.993 145.203 
144.493 437.809  -9.008
3                  -5      145.795 145.995 145.205 144.495 
437.815  -15.014





73,
Scott H. Stevens / N3ASA
ARISS Team Member
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