OMID signals on 465.0 MHz

First signals

Omid was probably launched around 1834-1836 UT on 2 February 2009 along a track as shown below. I have used the launch site location suggested by and plotted a line at 55.5 degrees inclination through it.

I received my first signals in Stockholm ,Sweden a day later on February 2009 at 1844.30-1846.30 UT
in Mode 1 (see "Mode 1" below).

"Mode 1"

The spectrogram below was received on 4 February at 1717.50-1724.10 UT in Stockholm, Sweden using a discone antenna. The signal was commanded on. The carriers are 1 kHz apart. If one uses a narrow-band FM receiver to listen to the signals one hears a 1 kHz tone. The carriers in the spectrogram below are the classical result of modulating an FM transmitter by a tone. The amplitudes of the peaks in the resulting spectrum are determined by Bessel functions of the first kind with the modulation index as their argument. Some spectral components can be zero for some modulation indices, but this does not explain why the spectrum is somewhat asymmetrical.

10.7 MHz in diagram = 465.00 MHz

"Mode 2"

The spectrogram below was received in 4 February at 1852.40-1856.30 UT in Stockholm, Sweden. The two signals are about 3 kHz apart.

Signals on 5 and 6 February 2009

I missed the only active pass over Europe on the 5th (heard in the UK by Robert Christy) , but picked up Omid again on the 6th on its last pass over my horizon that day. It was in Mode 1 at 1743.30-1747.08 UT. The signal was strong. So, the story continues.

A picture of Omid and its antennas

I found this picture of Omid at the web site of the Iranian Space Agency. The two sets of whip antennae on two faces of the spacecraft box have two different lengths, possibly related to the uplink at 401 MHz and the downlink on 465 MHz. The Iranian Space Agency web site gives the dimensions of Omid as 40 x 40 x 40 cm - if I read the text correctly - it is all in Farsi!

Signals on 7 February 2009

No signals during over-the-horizon passes from Omid until the very last moments of the last pass of the day when it appeared in Mode 1 at 1758.25-1759.15 UT.


More information about Omid can be found on Robert Christy's website.

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