Differences

This shows you the differences between two versions of the page.

--- vhfwxsatellitetips [2021/08/01 23:40] – mm3iig
+++ vhfwxsatellitetips [2022/05/08 01:39] (current) – [OARC VHF Weather Satellite Reception Tips & Tricks] mm3iig
@@ Line 2: / Line 2: @@
 {{ ::meteorheader1500x500.jpg?nolink&800 |}}
+//Meteor-M2 LRPT capture of the Eastern Atlantic and the U.K. & Ireland - MM3IIG//
-This is the first draft of what will hopefully become a useful club resource for people wanting to do some VHF satellite reception of either NOAA APT signals or the LRPT signal from the Russian meteor satellites. There’s no need to reinvent the wheel as plenty has been written before on this subject. Instead there will be links to other places around the Internet, but also some learned wisdom and tips from OARC members. It is unfinished and may get broken up into separate pages once it becomes unwieldy.
+This is the home of what will hopefully become a useful club resource for people wanting to do some VHF satellite reception of either NOAA APT signals or the LRPT signal from the Russian meteor satellites. There’s no need to reinvent the wheel as plenty has been written before on this subject. Instead there will be links to other places around the Internet, but also some learned wisdom and tips from OARC members. The guide is split into sections and you can always get back to the index by using the breadcrumb links up at the top.
-VHF satellite work is the easiest satellite reception work to get into. If you get the bug after doing this consider moving up to L-band HRPT reception, which should doable with a modest antenna. The next step up from that is to geostationary satellites, where you'll be needing amplifiers, filters, and a whole lot of kit. There are a few places on the internet that specialise in this kind of thing.
+VHF satellite work is the easiest satellite reception work to get into. If you get the bug after doing this consider moving up to L-band HRPT reception, which should doable with a modest antenna. The next step up from that is to geostationary satellites, where you'll be needing dishes, amplifiers, filters, and a whole lot of kit. There are a few places on the internet that specialise in this kind of thing.
+To-do: Finish the antenna section (plus links!), maybe a bit more about radio choice, and any other suggestions that you guys want.
+Mark MM3IIG
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 ===== Contents =====
-  * [[vhfwxsatellitetips-antenna|Antenna considerations + links to projects]]
+  * [[vhfwxsatellitetips-antenna|Antenna considerations + links to projects]] - some links to plans, discussion on options, and some tips from members
-  * [[vhfwxsatellitetips-hw|Extra Hardware]]
+  * [[vhfwxsatellitetips-hw|Hardware overview]] - including SDRs/radios, low-noise amps, and bandpass filters
-  * [[vhfsatellite-sw|Software overview + tips]]
+  * [[vhfsatellite-sw|Software overview + tips]] - some of the software used to do this work is awful - here's some useful tips for various APT/LRPT applications
+  * [[vhfsatellite-general|General tips/data for APT and LRPT decoding]] - some discussion on the signals in general, a list of frequencies, and some last-minute "gotchas" to avoid
-====== General tips/data for APT and LRPT decoding ======
+  * [[vhfsatellite-gallery|OARC reception gallery]] - some shots from around the club
-<WRAP left round info 25%>
-===== Frequency list =====
-  * **NOAA-15:** 137.6200
-  * **NOAA-18:** 137.9125
-  * **NOAA-19:** 137.1000
-  * **Meteor M-N2:** 137.1000
-</WRAP>
-Obviously for those of you wanting to do LRPT as well you will have to deal with the overlap and shared frequency of NOAA 19. This is always irritating and there isn't much you can do. An APT signal will destroy a digital LRPT signal, and if you try decoding APT with LRPT in the background it will show discernible shapes, but nothing really useful to work with. The best thing to do is to wait a few days for their orbits to diverge from each other.
-**APT:** FM, 34 kHz signal, set filter bandwidth to around 35-40 kHz. If you’re correcting for Doppler you can maybe go towards the lower of the range to block out more of what you don't need, but if not go for 40 to get the whole thing in and account for the +/- Doppler difference, approximately 3 kHz.
-**LRPT:** FM, 120 kHz signal, set filter bandwidth to around 130-140 kHz. Doppler correction isn’t strictly needed as the demodulator tools can pick out the data and lock onto it just fine. An SNR of around 10 dB will decode fine, but you may even get some data coming through around 5-10 if you're lucky. Just don't expect a great, error-free capture. Once you hit around 15-20 dB you're laughing.
-For LRPT work remember that it’s the raw I/Q baseband recording that you want if you aren't decoding live, not an audio recording. For APT you want the audio recording.
-<WRAP center round important 60%>
-If you’re switching between receiving the two types of signal don’t forget to check your Doppler/recording settings are suitable for each one! MM3IIG has lost more than one capture because of this kind of silliness...
-</WRAP>
-If you can avoid DC spikes by using offset tuning or a filter function it can help, particularly with LRPT. If it’s baked into your recording and you're using SatDump then there’s an option to block it as the file is read.
-You'll need more gain for LRPT signals because of the similar power but lower bandwidth (power density). This can induce intermod/breakthrough depending on your antenna, location, etc. If that happens you may want to look into bandpass filters for 136-138 MHz.
-===== Audio Samples =====
-Here's a couple of audio samples to test your software setup with. There's a WAV audio recording for APT and an LRPT test with a baseband I/Q WAV recording (i16, 250000 kbps sample rate).
-<WRAP left round info 40%>
-==== APT Sample ====
-,025 kHz mono WAV file, (size here)
-  (link here)
-</WRAP>
-<WRAP right round info 40%>
-==== LRPT Sample ====
-kHz wide baseband I/Q WAV file, (size here)
-  (link here)
-</WRAP>
 ----
-====== OARC reception gallery ======
+===== Community Links/Further Info ====
-If you're adding entries please add the start time of the pass, or for composites feel free to specify a time range.
-===== APT Captures =====
-^  Capture  ^  Date  ^  Time(s) (UTC)  ^  Callsign/Name  ^  Notes  ^
+There’s lots of places where you can find some more information on reception, software, antennas, and all other relevant topics:
-^  [[https://ibb.co/QvKHgWT|{{https://i.ibb.co/QvKHgWT/07211107-MSA.jpg}}]]  |  21/07/2021  |  11:07  |  MM3IIG Mark  |  NOAA-18, Multi-spectral analysis  |
-^  [[https://ibb.co/3TmrQCB|{{https://i.ibb.co/3TmrQCB/0721-Composite.png}}]]  |  21/07/2021  |  9am-12pm  |  MM3IIG Mark  |  NOAA-18 & 19 composite, Multi-spectral analysis. This is composed of 4 passes  |
-^  [[https://ibb.co/SRXn11L|{{https://i.ibb.co/SRXn11L/noaa-18-07151040-norm.png}}]]  |  15/07/2021  |  10:40  |  M7SMU Simon  |  NOAA-18, normal view of a single channel  |
-^  [[https://ibb.co/q0dK8Hn |{{https://i.ibb.co/q0dK8Hn/4256-B1-EF-02-BE-481-C-BA30-8-F6-F79-A1-EE12.gif}}]]  |  26/07/2021  |  8am-11am  |  M7SMU Simon  |  Animation created by MM3IIG using Simon’s captures  |
-===== LRPT Captures =====
+**Reddit:** https://www.reddit.com/r/amateursatellites/ - Amateur Satellites subreddit, which does lots of weather satellite reception as well as amateur radio satellites.
-To follow.
+**LibreSpace:** https://libre.space - Has a forum where you can ask about reception and rotors/tracking etc.
-^  Capture  ^  Date  ^  Time(s) (UTC)  ^  Callsign/Name  ^  Notes  ^
+**Twitter:** Putting terms such as “meteor”, “LRPT” and the names of the NOAA satellites into Twitter can net you lots of new people to follow who are good sources of help, plus images of passes you can compare your captures with. A lot of the people on these places overlap, though. The community is a small but friendly one.
-^  [[x|{{x}}]]  |  x  |  x  |  x  |  x  |