How to Track Satellites With a Compass

compass

I explain how to do this at the end of the following video. I explain this in text form below the video links, with elevation estimation and some other tips as well.

https://youtu.be/StJbYHSMwt0?t=971

Full explanation starts earlier at

https://youtu.be/StJbYHSMwt0?t=901

Direction Estimation

Get a real compass as the one on your phone may not be reliable.

Read the azimuth degrees on your tracking software of where the bird is coming from (start of pass), where it will be at maximum elevation (middle of pass) and where it will be when it goes away (end of pass).

Find something in the distance at each of those points you can use as a marker and memorize them.

Memorize the time of the beginning, middle, and end of the pass. These may be indicated as AOS, TCA, and LOS, respectively, on some prediction applications.  AOS means Acquisition of Signal, TCA means Time of Closet Approach, and LOS means Loss of Signal.

Throughout the pass check the time on your watch to track it. You can estimate where the satellite is based on all this information. You can use your tracking app to supplement this, but learning how to track manually is very helpful as it will increase your situational awareness.

Direction Estimation by Following the Signal

Depending on the satellite you’re tracking you can also track it by “following the signal.” If you hold the antenna in one spot for a while, like when it’s first coming over the horizon, and then notice the signal getting weaker you need to move the antenna further along in the estimated path it will take as it flys by you. Some signals are too strong or too intermittent to allow for this type of tracking.

Luckily the most popular “easy sat,” SO-50, is perfect for this because its signal isn’t too strong and if you are in a populated area it will be transmitting very frequently as people use it almost constantly through a pass. AO-85 is so powerful you don’t have to be aiming your antenna very precisely to pick it up. Since the ISS digipeater’s transmissions are only seconds long, and they can be several minutes apart, it’s hard track the ISS digipeater by following the signal.

Elevation Estimation

To estimate the elevation of the satellite remember that 0 degrees is flat and 90 degrees is straight up. 45 degrees is in the middle of 0 and 90.

A rule of thumb is if you make a fist and hold your arm flat, the top of your fist is 10 degrees above the horizon. Move your fist up one “fist length” and now you’re at 20 degrees. Raise it one more fist length and now you’re at 30 degrees, and so on and so forth.

While one first length at 10 degrees may not seem like a high elevation, it is easy and common to underestimate how high 10 degrees is. I think if you look  far off into the distance at an object, as the 10 degree angle continues to rise you might realize 10 degrees is surprisingly high.

If you go up four fist lengths you’re almost at 45 degrees, As I implied earlier 45 degrees is easy to estimate because it’s in the middle of 0 and 90. If you look at that angle by holding your arm out you’ll see 45 degrees is pretty high, so if 10 degrees is almost a quarter of 45 degrees (remember it’s four fists lengths to almost 45 degrees), 10 degrees is pretty high too.

This is Hard

Doing all of this effectively takes a lot of practice. If you watch some of my videos you’ll see I often lose the bird. I haven’t gotten reliably good at it until recently after I started  operating sats at least once a week for weeks in a row, and really I had to operate multiple times a week for weeks in a row to start to feel regularly confident.

I’m still not able to always track it properly. The hardest thing for me to realize is when it’s a high elevation pass it transitions from one side of your body to the other side VERY fast, within seconds.

When you start out you with sats you look for high elevation passes because you know the satellite will be easier to hear because it will be closest to you if it’s going right overhead, but the relative speed at high elevation is so high it can also make tracking it much harder than it would be on a lower elevation pass.

A 45 degree pass might be a lot easier to track than a 90 degree pass if you’re new. The most important thing, like learning all things, is to just keep trying. If you spend enough time practicing eventually you will get good at it.

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