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Registered Member #2431
Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639
Power Radio Antenna Masts for Cars, Auto Raising/Lowering.
Does anyone now how these work? i need to give a bot a longer reach to pick and at poke stuff, doesnt need to be very strong.
ive seen some rather worthless explanations of a "nylon cord" and gear, that winds up from a tiny motor. but is there a spring inside the antenna, as strings can only pull not push? right?
Registered Member #2529
Joined: Thu Dec 10 2009, 02:43AM
Location:
Posts: 600
I used to have one, I've never taken one apart but it's reasonably intuitive how it works from the shape.
AFAIK it's just a somewhat flexible thinnish plastic rod wrapped around a pulley on a motor. When you want to extend it, it unwinds and pushes inside a telescopic aerial and that extends it. There's probably bearings/wheel things at strategic places around the pulley to stop it jamming.
Registered Member #2463
Joined: Wed Nov 11 2009, 03:49AM
Location:
Posts: 1546
Look in Ham Radio sites, like QRZ. Screwdriver aerials are popular, and there are also those who refurbish these units when the start to wear out. Also, with your high voltage history, you might include a voltage sensor, lest your bot reach out and touch something that touches you back.
Registered Member #2431
Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639
ok ive got a 34.5 inch stainless steel one on the way... ~14 USD or so plus some shipping.
im wondering how fast they can be deployed and retracted, and how much sag with 30 grams on the tip , in a -45 degree down angle. Also i cant wait to see how much force/torque it takes, im hoping a HiTec HS-55 servo will be good enough.
i have several of the HS-55 for my U-dar proximity/distance ranger :
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Power Radio Antenna Masts for Cars, Auto Raising/Lowering.
