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balloon [2014/11/03 10:05]
cwh0009 created
balloon [2014/11/03 14:47] (current)
cwh0009
Line 6: Line 6:
   * Operates on 144.39   * Operates on 144.39
   * Transmits APRS packets with GPS coordinates   * Transmits APRS packets with GPS coordinates
-  * Need to use high altitude version of GPS or you'll get tracking errors introduced ​(intended to prevent GPS from being put in a missile)+  * Need to use high altitude version of GPS or you'll get tracking errors introduced 
 +    * The error is intentional and intended to prevent GPS from being put in a missile ​guidance system. 
 +    * High altitude version has a higher cap for altitude but lower top speed. 
 +  * Configure with call sign 
 +  * Default packet encoding is mic-e, turn this off for plain text APRS packets 
 +  * Hanging antennas are great for balloons while they'​re in the air. 
 +    * Can get fouled up or caught on stuff during the landing. 
 +    * Hanging antennas don't work very well if it lands on the ground - tend to coil up and end up with a payload sitting on them.
  
 ====== Cutdown System ====== ====== Cutdown System ======
 Need two methods of "​cutdown"​ (bringing the balloon down from altitude) to fulfill regulatory requirements by FAA Need two methods of "​cutdown"​ (bringing the balloon down from altitude) to fulfill regulatory requirements by FAA
   * Bursting balloon counts as one, so you only need to design one method of cutdown (unless you launch an under-inflated or balloon using a non-conventional material)   * Bursting balloon counts as one, so you only need to design one method of cutdown (unless you launch an under-inflated or balloon using a non-conventional material)
-  * Melting the rope connecting payload to balloon is a common ​one +  * Melting the rope connecting payload to balloon is a common ​method of cutdown 
-  * Parachute release mechanism +    * May have trouble generating enough heat to melt through rope 
 +    * Conduction of heat through air is lower at altitude, air is colder, so it takes longer to melt 
 +    * If the rope fuses to the cutdown system then it's not going to work 
 +  * [[http://​commons.wikimedia.org/​wiki/​File:​3Ring_release_animation.gif|Parachute release mechanism]]
  
 ======= Regulatory Stuff ====== ======= Regulatory Stuff ======
 +Not as many as you'd think, it's pretty easy for private citizens and groups to launch balloons provided you follow some rules the FAA and FCC have in place
 +  * Notify FAA air traffic controller nearest the site of operation 6 to 24 hours before launch
 +  * Individual payload must be less than 6 pounds
 +    * You may have multiple payloads hanging from the balloon provided they are under the weight limit
 +    * The total payload has a maximum weight of 12 pounds
 +  * It is illegal to put a cellphone in a balloon for the purpose of tracking the balloon.
 +    * Cellphones make poor tracking devices anyway, there'​s no cell service at altitude. Stick to radio beacons.
 +  * The rope used to connect the payload to the balloon should break when 50 pounds of force is applied.
 +  * You may not launch projectiles or gliders from the balloon.
 +  * Do not operate the balloon over a restricted area.
 +    * Don't fly over military bases or airport airspace. ​
 +  * Do not launch a balloon between sunset and sunrise unless it is equipped with lights that are visible for      at least 5 miles and have a flash frequency of at least 40, and not more than 100, cycles per minute.
 +  * If your antenna is longer than 50 feet, it needs to either snap with less than 50 pounds of force or be covered in brightly colored streamers visible for 1 mile.
 +  * Weather conditions need to permit the launch.
 +    * Cloud cover must at any altitude must be less than half the sky.
 +    * Any altitude under 60,000 feet must have 5 miles of visibility.
 +
 +There are more rules that apply if your balloon doesn'​t meet the Title 14 Part 101 §101.1 exemptions, so try to follow them.
balloon.txt · Last modified: 2014/11/03 14:47 by cwh0009