NOAA 18

[SA_tx_88116]

I'm currently trying to hear the NOAA 18 satellite while tracking it right now and my radio for some reason has a good signal on the downlink frequency (137.9125) even though the satellite is all the way down in south America right now is there something I can do to actually receive the satellite and not some random radio signal? Also does NOAA 18 use FM or any squelch tones?

 

[kb5udf]

Regarding software, I think WXtoImg supports most of what you want but it’s been a while. Your noise is a tougher problem.
I’d try the usual local noise mitigation techniques, like powering down most of your house and all a/c adapters. Failing that, unless you can aim a directional antenna, I’m not sure what else would be of practical benefit, other than trying a different sat/freq.

 

[SA_tx_88116]

Regarding software, I think WXtoImg supports most of what you want but it’s been a while. Your noise is a tougher problem.
I’d try the usual local noise mitigation techniques, like powering down most of your house and all a/c adapters. Failing that, unless you can aim a directional antenna, I’m not sure what else would be of practical benefit, other than trying a different sat/freq.

The satellite uses FM right?

 

[kb5udf]

As I recall yes, I forget the exact bandwidth, but its a little wider than a typical 5hz deviation FM signal will audio output from a scanner (that used to work, but you would get reduced quality images. To see images the way intended, we used to tap the discriminator output of the scanner, but with an SDR you can set bandwidth as you need. I would add that if your radio has an audio output for 9600baud packet, that might also give you the signal you need, at least it should work better than the filtered FM audio output (and by filtered audio output I mean a speaker/headphone jack output).

 

[wtp]

137.9125 MHz and 137.1000 MHz
The APT signals transmitted by NOAA satellites are RHCP (Right Handed Circularly Polarized), so it takes an RHCP type antenna to produce a good signal reception
bandwidth of 34 kHz
and that is from

https://www.matec-conferences.org/articles/matecconf/pdf/2018/77/matecconf_iciee2018_02002.pdf

but i thought years ago i found another article that said the bandwidth was 40khz.
and any other kind of antenna can hear it, just not as well.
edit: NOAA APT Satellites transmit on frequencies between 137.1000 and 137.9125 MHz FM using between 30 and 40kHz bandwidth.

 

[SA_tx_88116]

137.9125 MHz and 137.1000 MHz
The APT signals transmitted by NOAA satellites are RHCP (Right Handed Circularly Polarized), so it takes an RHCP type antenna to produce a good signal reception
bandwidth of 34 kHz
and that is from

https://www.matec-conferences.org/articles/matecconf/pdf/2018/77/matecconf_iciee2018_02002.pdf

but i thought years ago i found another article that said the bandwidth was 40khz.
and any other kind of antenna can hear it, just not as well.
edit: NOAA APT Satellites transmit on frequencies between 137.1000 and 137.9125 MHz FM using between 30 and 40kHz bandwidth.

Also how do I decode the pictures?

 

[kb5udf]

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