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A project log for NOAA LB-CD

My take on an autonomous satellite image collector grabbing from NOAA 15/18/19. (Leave Behind - Collection Device)

nate-schroederNate Schroeder 01/06/2020 at 22:470 Comments

Well progress has been made on the antenna structure. I believe everything is wired right with the antenna. I followed this instructable but ended up modifying my antenna once I understood how it functioned. The antenna instructable has the coax as part of the loop. This revision I had problems with and could only hear the satellite after I tuned the antenna by rotating it and watching the waterfall on SDR#. The design I used actually just uses two loops of wire and are connected in a caddy corner fashion at the top of the antenna and one loop is connected to the coax shield and the other loop the signal. I found this wiring diagram the most helpful and easy to understand, although this antenna really isn't that complicated after you think about it for awhile, or a long while, a really really long while.

I also got all the software and scripts running on the Pi, however I think I have an issue. My recordings are really long. Like 1 hr+. Which doesn't make any sense to me because each pass is around 15 mins. The predict software is spot on with my coordinates because when I look at the schedule of satellite passes they match with NY20 online tracking. The result is that I get garbage for results. Here is a link to a pass and the results (the audio and images). Around the 30 min mark I am getting (I think) pretty good reception, and it lasts for what I am assuming is the full length of the pass. However, when the recordings 70 mins, I think it is getting lost in the noise. I plan on doing a fresh install on the Pi and redoing the scripts because maybe a dependency for GQRX is messing with rtl_sdr? If anyone has any suggestions about this, it would be greatly appreciated. I modified the rtl_fm command that runs to correct for the RTL's PPM offset so I think that is correct. Here is the tutorial I used for the Pi automation. It uses a Noolec SDR so that's why the rtl_fm command is slightly different, I think. This is starting to become a little bit of a rabbit hole. If I do a fresh install and still can't get clear results I am not sure what should be next. Maybe a nice paper weight? Nah, I'll keep messing around and see what happens.

Looks cool nonetheless. I could only imagine what people driving by looking in the window think I'm doing. If I told them I was talking to satellites vs. summoning aliens I'm not sure which would be more believable.

(The electrical tape is temporary. I want to make sure it works before gluing it up in case I need to take it apart.) 

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