[Date Prev][Date Next][Thread Prev][Thread Next] - [Date Index][Thread Index][Author Index]

Re: working ISS



Hi Francesco:

If ISS is on 2meter mono band, then doppler is only
3.3k max.
Doppler adjustment on 2meter FM is optional.

If ISS is on the 440 band, then will need to adjust
for doppler.

This link has some 2-meter iss dopppler ajustmenst
posted.
http://www.marexmg.org/fileshtml/isspacketmanual.html

Attched is a memo from Ken about adjusting doppler for
440 for ISS
***


This weekend (Jan 14-15 UTC) Bill McArthur plans to
operate on the UHF 
band
exclusively. It is his desire to work all continents
on the UHF band 
from
the International Space Station.

The frequency he will be using will be 437.55 simplex.
Due to the high
Doppler effect on this band, one will need to operate
split frequencies 
for
most of the pass. A very simplified chart showing
memory assignment for
transmit and receive with 5 KHz spacing is below as an
example .

Mem.     TX     -    RX
Ch A - 437.540 - 437.560  Acquisition of signal (AOS)
Ch B - 437.545 - 437.555
Ch C - 437.550 - 437.550  Time of closest approach
(TCA)
Ch D - 437.555 - 437.545
Ch E  -437.560 - 437.540  Loss of signal (LOS)

Good Luck and 73,

Kenneth G. Ransom - N5VHO
ISS Ham Radio Project Engineer
Johnson Space Center
Houston, TX 

--- Francesco Messineo <iz5dwf@amsat.org> wrote:

> Hello,
> 
> I work LEOs with a portable setup since some years
> now, I have two 
> all-mode radios and a couple of home made arrow like
> two band antennas.
> Now I thought it would be good to work also the ISS,
> but I haven't yet
> found a good working practice. I mean, with LEOs I
> work full duplex
> so I know when I'm getting into the sat and I can
> adjust both 
> frequencies (well, try to adjust them in the right
> manner at least) to
> have a good signal and I can unkey if I don't hear
> myself on the sat.
> With the ISS I have no way to  know if I'm getting
> heard and also I 
> can't adjust up and downlink frequecies at the same
> time (I use the
> -600 KHz shift on transmit, but obviously it doesn't
> work right as
> the doppler shift change direction from rx to tx).
> Now I'd like to
> know if someone has any good advice on working the
> ISS with portable
> setup. My RTX are a TR-9130 and a TR-851. 
> Any hint is welcome
> 
> best 73
> 
> IS0FKQ (ex IZ5DWF)
> ----
> Sent via amsat-bb@amsat.org. Opinions expressed are
> those of the author.
> Not an AMSAT member? Join now to support the amateur
> satellite program!
> To unsubscribe, send "unsubscribe amsat-bb" to
> Majordomo@amsat.org
Just $16.99/mo. or less. 
dsl.yahoo.com 
----
Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
Not an AMSAT member? Join now to support the amateur satellite program!
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org



AMSAT Top AMSAT Home