This thing shouldn't be covered in ice. It's supposed to heat up and melt the ice as it forms.That part isn't working. Did I mention it's about a thousand feet above the ground? Tried to send a crew up for a closer look yesterday but the ice was starting to melt and fall in big pieces and even with hard hats and tennis racquets, it was too dangerous.
Are we having fun yet?
Fun like this, I would as soon not have.
For scale, that's a normal-sized ladder at the lower left. The red part is a little over a hundred feet from end to end.
Busted defranistator.... hate it when that happens.
ReplyDeleteI'll say..... there isn't enough money available to get me to climb that tower, ice or no.
Not enough money or guns -
DeleteTennis raquets?
ReplyDeleteIs that some new high-tech tool I'm not aware of?
So what's the deal? Thermostat that decides when to turn the de-icers on or the relay, etc. that the thermostat controls no worky?
ReplyDelete(I know how to do de-icing on airplanes and such but not on the ground, hence the use of the technical term "worky.")
And I like your use of the phrase "Send a crew."
Literally "send:" there's an elevator, but no controls in the car. They're at ground level.
ReplyDeleteThe de-icing system directly detects the formation of ice, by sensing the detuning of a high-stability mechanical oscillator in an exposed location. (It is locked out of the temperature is above 40.) When it detects ice, it de-ices itself (the element is the size of a fat pencil) and turns on the de-icers for a set period of time. If ice reforms, it retriggers the de-icers. And the fun part? The "de-icers" are also the spiral antenna elements you see in the photo; they use some clever tricks to send high-current, low-voltage AC through them and warm them up without bothering radio frequency energy they are radiating.
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DeleteThank you for the enlightenment.
ReplyDeleteI'm still of the "see ice, turn on sequenced de-icing elements, let them cycle" school. And I certainly no experience with de-icing an antenna itself.
I wondered if the de-icers were separate from the antenna elements and how well they worked and played together.
Just send microwaves through the coax for a few seconds....
ReplyDeleteMelt the ice.
IIRC something like 1.2 GZ or something?
B: Your theory fascinates me, and I wish to subscribe to your newsletter. ;)
ReplyDeleteMicrowaves from what source? Magic microwaves that don't cause dielectric heating of the PTFE insulators in the coax? That get through the much lower frequency power dividers? ...etc.
It's never as easy as Don Channing and Kimball Kinnison made it look.
It is always fascinating to consider what happens at radio frequency. Even folks who deal with DC and 60 hertz stuff get confused.
ReplyDeleteShow an electrician a loop antenna and watch the steam come out of their ears. "That's a short-circuit! That can't possibly work."
Indeed. I was, of course, joking. If it were that easy, anyone (and everyone) would do it and there wouldn't be the incredibly complex de-icing systems in use.
ReplyDeleteIt is really simple until actual physics just come up and slap you in the face....
Out of interest is the main problem with the weight of the ice or a reduction in the range / signal strength?
ReplyDeletePretty much "yes." It's all bad. SWR goes up, range is reduced, the antenna can be damaged.
ReplyDeleteThanks, at lest it did not fall down like this one I was taken to see as a kid. http://en.wikipedia.org/wiki/Emley_Moor_transmitting_station
ReplyDeleteQX to your Kim Kinnison name-check, ace. :-)
ReplyDeleteDon's Channing's main contribution was to organize and otherwise stay out of the way of the mad scientists and irritated engineers, IIRC. It was Walter Franks who made things look easy.
ReplyDelete