[amsat-bb] Working SO-50

[Ib Christoffersen]

Working SO-50.

I think it is time to look at how one can operate over SO-50 and the
problems that can be encountered.

First the normal and nominal data:

Uplink is at 145.850 MHz. Downlink at 436.795 MHz.

If it is not ON - use 74.4 Hz CTCSS tone to activate the transmitter for 10
seconds to have it on for nominally 10 minutes - when on use 67 Hz CTCSS
tone during your transmission.

That was the intended normal operation.

Now to the deviations from the normal scheme.

The downlink frequency sometimes jump approximately 5 kHz. Therefore I have
two different frequencies pairs to be used in SATPC32:

SO-50,436788.50,145849,FM,FM,NOR,0,0
SO-50,436795,145850,FM,FM,NOR,0,0

If you do not use Full Doppler Tracking it is not much of an issue. Just
tune for best downlink.

Talking about SATPC32 here are the entries for the CTCSS tone:

SO-50,67.0,$3F,1
SO-50,74.4,$3E,3

The first data is for the ICOM IC-910 radio. If you use another radio please
look at the information in SATPC32.

Next problem is the change of polarity of the downlink signal during a pass.
The polarity changes during the pass. At least I have to switch polarity a
few times from RHCP to LHCP to optimize the downlink signal. That has been
confirmed by others. How it works using linearly polarized antennas I do not
know - but I think there will be some fading.

And if that is not enough - at least here over Europe - we have to put up
with QRM on the uplink from a lot of different sources like repeaters and
people using our frequencies as cheap phone connections.
The result of the QRM is that it sometimes is difficult to turn SO-50 on.
Also the QRM may turn the transmitter off.

And since the inclination is not sun synchronous we have to live with a
steady change of pass times over the year.

Some may think I am not a fan of SO-50. That is not the case. It is a very
good satellite we got for free and it works very well.
Already more people are using it over Europe after AO-51 is not with us any
more. That just took a couple of days.

73 OZ1MY/Ib

[Eric Knaps, ON4HF]

Hello Ib,

I agree with you.
This is what I have in my Doppler.sqf file for SatPC32:

SO-50,436790,145850,FM,FM,NOR,0,0
SO-50,436795,145850,FM,FM,NOR,0,0

and in my SubTone.sqf:

SO-50,67.0,$3F,1
SO-50,74.4,$3E,3

This is for the Yaesu FT-847.

73,
Eric.

Amateur Radio Station ON4HF
Eric Knaps
Satellite manager UBA


http://www.on4hf.be

Post by Ib Christoffersen
Working SO-50.
I think it is time to look at how one can operate over SO-50 and the
problems that can be encountered.
Uplink is at 145.850 MHz. Downlink at 436.795 MHz.
If it is not ON - use 74.4 Hz CTCSS tone to activate the transmitter for 10
seconds to have it on for nominally 10 minutes - when on use 67 Hz CTCSS
tone during your transmission.
That was the intended normal operation.
Now to the deviations from the normal scheme.
The downlink frequency sometimes jump approximately 5 kHz. Therefore I have
SO-50,436788.50,145849,FM,FM,NOR,0,0
SO-50,436795,145850,FM,FM,NOR,0,0
If you do not use Full Doppler Tracking it is not much of an issue. Just
tune for best downlink.
SO-50,67.0,$3F,1
SO-50,74.4,$3E,3
The first data is for the ICOM IC-910 radio. If you use another radio please
look at the information in SATPC32.
Next problem is the change of polarity of the downlink signal during a pass.
The polarity changes during the pass. At least I have to switch polarity a
few times from RHCP to LHCP to optimize the downlink signal. That has been
confirmed by others. How it works using linearly polarized antennas I do not
know - but I think there will be some fading.
And if that is not enough - at least here over Europe - we have to put up
with QRM on the uplink from a lot of different sources like repeaters and
people using our frequencies as cheap phone connections.
The result of the QRM is that it sometimes is difficult to turn SO-50 on.
Also the QRM may turn the transmitter off.
And since the inclination is not sun synchronous we have to live with a
steady change of pass times over the year.
Some may think I am not a fan of SO-50. That is not the case. It is a very
good satellite we got for free and it works very well.
Already more people are using it over Europe after AO-51 is not with us any
more. That just took a couple of days.
73 OZ1MY/Ib
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[PE0SAT]

Hi Ib,

Thanks for the information.

One thing I would like to add to the people that use HRD and a FT-847.

I tryed many times to work SO-50 but I am unable to do this with HRD.

When I want to make a QSO via SO-50 I allways have to use SatPC32.

I haven't figured out why CTCSS and HRD isn't working with SO-50.

73 Jan PE0SAT

Post by Ib Christoffersen
Working SO-50.
I think it is time to look at how one can operate over SO-50 and the
problems that can be encountered.
Uplink is at 145.850 MHz. Downlink at 436.795 MHz.
If it is not ON - use 74.4 Hz CTCSS tone to activate the transmitter for 10
seconds to have it on for nominally 10 minutes - when on use 67 Hz CTCSS
tone during your transmission.
That was the intended normal operation.
Now to the deviations from the normal scheme.
The downlink frequency sometimes jump approximately 5 kHz. Therefore I have
SO-50,436788.50,145849,FM,FM,NOR,0,0
SO-50,436795,145850,FM,FM,NOR,0,0
If you do not use Full Doppler Tracking it is not much of an issue. Just
tune for best downlink.
SO-50,67.0,$3F,1
SO-50,74.4,$3E,3
The first data is for the ICOM IC-910 radio. If you use another radio please
look at the information in SATPC32.
Next problem is the change of polarity of the downlink signal during a pass.
The polarity changes during the pass. At least I have to switch polarity a
few times from RHCP to LHCP to optimize the downlink signal. That has been
confirmed by others. How it works using linearly polarized antennas I do not
know - but I think there will be some fading.
And if that is not enough - at least here over Europe - we have to put up
with QRM on the uplink from a lot of different sources like repeaters and
people using our frequencies as cheap phone connections.
The result of the QRM is that it sometimes is difficult to turn SO-50 on.
Also the QRM may turn the transmitter off.
And since the inclination is not sun synchronous we have to live with a
steady change of pass times over the year.
Some may think I am not a fan of SO-50. That is not the case. It is a very
good satellite we got for free and it works very well.
Already more people are using it over Europe after AO-51 is not with us any
more. That just took a couple of days.
73 OZ1MY/Ib