commgrp@silver.ucs.indiana.edu (BACS Data Communications Group) (07/31/90)
davet@tsdiag.ccur.com (Dave Tiller N2KAU) writes: >Amen to the increase in static potential when snowing!! I got the >BeJesus shocked outta me when I reached over to tune my 10m Amateur >radio whilst traveling on a _metal_ suspension bridge (Del. Mem). I >figured at the time the snow added to the static buildup by imagining >all of those snowflakes hitting my antenna and losing electrons as >they slipped past. Ouch!!! I once flew a kite on steel wire-recorder wire (very strong and light; NOT recommended near power lines!) The sky was cloudless, but I got strong shocks from the wire spool. I presume that charge was building until there was sufficient voltage to discharge through my rubber shoe soles. Precipitation static (a mild form of St. Elmo's fire?) causes radio interference in vehicles, especially aircraft. Ever notice the flexible wicks attached to the trailing edges of aircraft wings? Those are for dissipating precip. static. Not all planes have them; my flight instructor once remarked that precipitation static is worse in Piper Cherokee-class aircraft than in Cessna 172's. That's probably because the trailing edges of Cessna wings are corrugated and have sharp points, whereas Pipers are smooth. I encountered precipitation static while driving through a blizzard in S. Dakota-- I heard a popping sound (about twice per second) and looked inside the hole in the dash where the radio had been removed. I saw sparks jumping across the end of the antenna connector. The sparks stopped after about two minutes and did not recur, even though the snow intensity did not diminish. I've also seen CB (AM) radio interference while driving in snow or rain in mountains: Noise builds up in the radio, then abruptly stops as the static discharges to ground (across the tires?); then the cycle repeats. _Popular Electronics_ magazine in the '60s published an article about an electrometer for monitoring atmospheric voltage. It was a pentode tube with a grid cap, on which was mounted a circular metal plate about 8 inches diameter. -- Frank Reid W9MKV reid@ucs.indiana.edu
hbg6@citek.mcdphx.mot.com (07/31/90)
In article <52707@iuvax.cs.indiana.edu> commgrp@silver.ucs.indiana.edu (BACS Data Communications Group) writes: > >I saw sparks jumping across the end of the antenna connector. The >sparks stopped after about two minutes and did not recur, even though >the snow intensity did not diminish. > While driving through one of our infamous dust storms, I noticed an arc jumping from the antenna pin of my CB slip mount to the ground pin. (the radio was removed) The arc formed about two or three times per second. I always figured it was static buildup from the antenna but could never understand why it would happen in one location then stop a couple of miles down the road while still in the same storm. I also decided that the front end electronics in a CB must be a little more stout than I had thought. John ..................................................................... All opinions expressed are mine and not Motorolas, their loss. .....................................................................
bwhite@oucsace.cs.OHIOU.EDU (Bill White) (08/11/90)
In article <52707@iuvax.cs.indiana.edu> commgrp@silver.ucs.indiana.edu (BACS Data Communications Group) writes: > >I once flew a kite on steel wire-recorder wire (very strong and light; >NOT recommended near power lines!) The sky was cloudless, but I got >strong shocks from the wire spool. I presume that charge was building >until there was sufficient voltage to discharge through my rubber shoe >soles. > Where did you get the steel wire-recorder wire? I've been looking for such a beast. This isn't advisable practice, but if you have a very powerful model rocket (I designed one special for the purpose, with three D engines), you can take a lot of very light wire, coil it in a very loose spiral around the rocket, mount it to the fins, and launch the thing in the middle of a thunderstorm. Incidentally, if you choose to do this (on your _own_ property), make sure you don't launch with a cable (I used a radio remote), and that it's at least 2 miles from anything or anyone. Also, you need a good ground on the other end of the wire to make it work, and the fin size must be great enough to keep the rocket stable. Don't expect to salvage the rocket afterwards! -- | Bill White Internet: bwhite@oucsace.cs.ohiou.edu | | MURPHY'S FIRST COROLLARY: | | Nothing is as easy as it looks. |