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TomjNorthIdaho
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IP based pan-tilt rotator for microwave dish & camera

Fri May 24, 2019 6:50 pm

IP based pan-tilt rotator for microwave dish & camera

I hope I can find some answers here for what I am wanting to build - your input/thoughts are welcome.

Just like most WISPs, from time to time we need to fix & add & re-aim & upgrade remote located tower microwave communication systems.
Soooo, I'm wanting to build an IP based rotator/tilt system that is strong enough to mount some or all of the following below:
1, Hi-gain dish tight beam long-distance dish
2, IP zoom camera (so that I can visually see where the dish is pointed)
3, additional optional devices could also include
3-a, very bright tight-beam light (so that the distant far side might be able to see where my equipment is located and provide a reference point to aim the remote equipment my equipment
3-b, a low-cost small laser (same function as 3-a , but for more distant locations where the 3-a light might not be seen)
3-c, a 30 degree sector antenna (this would be an and/or to the hi-gain dish antenna depending on what the pan-tile system can support)
3-d , a metal ground rod (something like a 102 inch steel whip CB antenna - for lightning strikes if/when they happen)
I know I can pretty much forget about camera pan-tilt systems because they can't support the weight.
I suspect there are some existing ham radio solutions for an IP based pan-tilt rotator that do have the ability to hold most or all of the above and be able to sustain the outdoor tower environments.

Ideas ?

North Idaho Tom Jones
 
sindy
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Re: IP based pan-tilt rotator for microwave dish & camera

Fri May 24, 2019 7:32 pm

The lightning protectors provide something which is called protected area (different national codes refer to different angles) so I'd really recommend to install the lightning rod to the fixed base close to the rotator, not to the moving part. Doing so will also soften the requirements for the mechanical strength of the rotator.
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TomjNorthIdaho
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Re: IP based pan-tilt rotator for microwave dish & camera

Sat May 25, 2019 1:07 am

The lightning protectors provide something which is called protected area (different national codes refer to different angles) so I'd really recommend to install the lightning rod to the fixed base close to the rotator, not to the moving part. Doing so will also soften the requirements for the mechanical strength of the rotator.
Agree - With a tower mounted lightning rod, I figure it would be best to locate the rod in a location the dish would least likely ever need to be pointed.
 
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Re: IP based pan-tilt rotator for microwave dish & camera

Sat May 25, 2019 6:04 pm

interesting idea...
few points:
1) when looking for rotator, you have to deal with wind loading as well, so unless it's quite small dish, usual PTZ mounts will not do (they might work for <0.5m dish, but not more)
2) heavy-duty az/el rotators are quite expensive (google "SPID rotator" and you will see, expect at least $1k) but they are often quite well made and reliable.
3) control is often over serial port (or USB serial), when calibrated, you just tell it AZ/EL where to point. Unlike usual PTZ camera mounts, that doesn't have any feedback, AZ/EL rotators do have encoders and always know exactly where they are pointed. Would be possible to connect it to ROS and script some serial commands...
4) Main issue will be pointing precision and minimum step size, for precise pointing. When pointing it somewhere, finding azimuth is easy using map or google earth, then scan in elevation axis for best signal and you are done.
5) Most IP cams are quite useless for this, low resolution and bad image quality to really see any details far away. Laser from the dish feed might be better, but in the end if rotator is calibrated, you don't really need to see where it's pointing, just enter target AZ/EL and it will be there. But small camera is still handy, just to see if it's turning correctly, and to make sure no birds getting squished by antenna movement etc..
 
sindy
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Re: IP based pan-tilt rotator for microwave dish & camera

Sat May 25, 2019 7:25 pm

1) when looking for rotator, you have to deal with wind loading as well, so unless it's quite small dish, usual PTZ mounts will not do (they might work for <0.5m dish, but not more)
In this regard I like very much Mikrotik's parabolic grids which give the wind almost no chance.

4) Main issue will be pointing precision and minimum step size, for precise pointing. When pointing it somewhere, finding azimuth is easy using map or google earth, then scan in elevation axis for best signal and you are done.
Given the beamwidth of the reasonably small dishes at 5.8 GHz (leaving aside the 2.4 GHz), a step of 1 degree in both AZ and EL should be fine enough. 60 GHz links are a different story of course.

5) small camera is still handy, just to see if it's turning correctly, and to make sure no birds getting squished by antenna movement etc..
Which means the best position of the camera is also on the fixed part, not on the rotating one :)
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