[TowerTalk] De-icing anetnnas

[hanslg at aol.com]

So, can I conclude that I need about  5 W/foot as I believe we sometimes have an ice build-up of about 1"/hour. As I don't want to leave that on at all time I need to monitor the temperature AND the humidity. At about 32° and 95% we have a high risk of ice build-up, that's when I need power on. Start to be complicated. By the way; I have never been home during the ice storms that took down my antennas (and with my luck it will probably stay that way).

Hans - N2JFS


    

How much ice accumulates? YOu can figure out how much heat it takes to melt it (not much, really)..about 300J/gram.   Say a foot of wire (30cm) has 1 cm diameter of ice on it.  THat's about 23 grams/foot.. So, call it 7kJ to melt all that ice.  1W will melt that in about 2 hours. 
 
 AWG 20 wire is 10 milliohms/foot.  Run 100 mA through it, and that's 1W/foot. 

jimlux


 

You can easily monitor the wire temperature by measuring the resistance. 
Copper has a known substantial positive temperature coefficient. 
 
Rick N6RK