Anyone down south get their AM towers grounded out in the snow?

[spinjector]

So all through our little dusting of snow here in DC, I was worried our AM tower base insulators were going to get buried in the snow and ground out the towers.

But, I'm from Buffalo, and we have a bit more regular snow there, and I don't recall ever hearing of this happening - even at the old 50kw WWKB 1520, which is right on the shore of Lake Erie and looking right down the barrel of the Lake Effect Snow Cannon.

Is this a real danger? Or would it be more likely to arc and vaporize the snow away?

 

[Bengalsfan]

Unless the top of your concrete pier is at ground level, I don't think you have anything to worry about. Atlanta reported 4" of snow. Most base insulators sit a little higher than that.

 

[spinjector]

What about two-foot piers in three feet of snow? =-)

 

[TomT]

I vaguely recall seeing the base of a Class IV's tower after a big snow. Bowl-shaped depression around the bottom of the tower where the snow was "burned off."

 

[BobOnTheJob]

I'd think there would be a big difference between heavy wet snow (which rarely gets 3' deep & doesn't drift) and the dry stuff that does drift. The dry stuff probably wouldn't conduct very well...

 

[spinjector]

Ah ok... Like I said, I'd never heard if it happening, but thought I should ask.

 

[K4WRF]

So all through our little dusting of snow here in DC, I was worried our AM tower base insulators were going to get buried in the snow and ground out the towers.

But, I'm from Buffalo, and we have a bit more regular snow there, and I don't recall ever hearing of this happening - even at the old 50kw WWKB 1520, which is right on the shore of Lake Erie and looking right down the barrel of the Lake Effect Snow Cannon.

Is this a real danger? Or would it be more likely to arc and vaporize the snow away?

Now I have never attempted to measure the impedance of snow at medium or any other frequency and I doubt I ever will. As pure as it is distilled water, would not be very conductive. I have seen iced up base insulators and guywire johnny balls crusted with snow. NO changes in impedance observed and no problems even at 50 kW fully modulated.

In todays high speed antenna fault detection any arc would take the transmitter off not allowing that amount of power to vaporize much if anything.

If it is causing a problem, I would think that it is a symptom of some other issue caused by the weight of the ice or something like that.

Freezing ground and snow pack can cause havoc with monitorpoint readings.

 

[boiseengineer]

Snow & ice can be contaminated enough to be conductive. An 1/4" ice storm or freezing fog/smog raises hell with some directional AM arrays around here. Especially the one with a folded unipole.

 

[spinjector]

Snow & ice can be contaminated enough to be conductive.

That's what I was thinking. Water needs to nucleate on something else or be agitated sufficiently to crystallize. That's why there's clouds in the upper atmosphere with water that's still liquid at minus-70 and colder. But once it comes down here where the dirty humans are, it finds a dirt particle in the air and then a snowflake starts to grow.

Have you ever seen the super-cooling videos on Youtube? Kinda cool. Works the same way as those liquid chemical handwarmers from the sporting goods store that you boil to recharge:

http://www.youtube.com/results?search_query=supercooling&search_type=&aq=f

24oz of water, from liquid to frozen solid in 3 seconds:

http://www.youtube.com/watch?v=HL8XCHPzj1c

 

[Bengalsfan]

What about two-foot piers in three feet of snow? =-)

If you regularly get three feet of snow and only built a 2 foot pier, then you should probably find another line of work.

 

[PTBoardOp94]

I'm guessing spinjector was referring to the Washington DC area, where they don't regularly get 3 feet of snow, but they did last weekend.

 

[spinjector]

Yea. I heard it said this was the most we've got since they started keeping records. ;D