开云体育

Lots of "hand waving" data here. Suggest you take a look at:

?

?

There is also an extensive study buried in the "Journal of the Franklin Institute". I remember reading 20,000 ampere per microsecond average rise times. I think I recall calculating the volts per meter on a #6 ga. copper ground (vertical) at 10kV per meter resistive and 100kv/m inductive and a final temp of 180 F afterwards.

?

?

I still wonder the grad student who was watching a Tektronics oscilloscope connected to the .001 ohm current sense resistor at the base of the lightning tower. There is mention in the paper that one giant bolt exploded the special resistor.?

?

There are also "super bolts" that you just can't protect from, but fortunately they are very rare and mostly sky to sky.

?

My personal antenna lightning solution is to always disconnect all feed lines and drag the ends 20 feet from the house. I live at the top of a 900 foot hill and used to get struck about two or three times a year. Many, many telephone lines replaced. As my grandparents said, "If the telephone rings during a thunderstorm, do not answer it!". For years, until I rebuilt the kitchen, there was a 1/4" melted burn at the edge of the kitchen sink caused by a lightning exploded telephone. The family dog was never the same after that.

?

Jim/VEZ

The intent of my comment was not to change the topic; rather to ask the question; "If a flat [sheet metal, such as copper] conductor is a lower inductance than a round [copper/aluminum] conductor, shouldn't it be well suitable for a receive-only loop?"

?

I believe it would work just fine.

?

ON THE OTHER HAND... there is a lot more wind resistance with a flat conductor.? Even a small flat-conductor loop would require a very stout mounting and construction to withstand anything more than a light breeze.

--

Phil, K0TWA

Well I finally got around to putting something together to test some receiving. I ended up getting the improved LZ1AQ from N4CY. For the loop I took a 4” x 10’ strip of 16oz copper approx 22mils or .0216” thick. I hemmed both long sides, also called a blind edge. The hem is .6 inches bent back onto itself and smashed flat in the brake, this helps give it some rigidity. After that I used the 3 pin roller to make a 3.18’ diameter loop. I drilled 2 opposing holes in a 10’ piece of 3” PVC and notched top with a uni bit. I took a 10” section of 3/4” pex tubing and cut 6” off of it. I placed one end in one of the pre drilled holes then bent it around top and put the other end in the opposite hole to form a circle slightly smaller than my copper loop. Attached the amplifier box and bolted on my loop. Not too crazy about the loop to amp connections, the #6 bolt and wingnut doesn’t seem sufficient to me, id like to try something that is in contact with more of the copper surface. My bias tee power supply was noisy so i had to track down a better one.?
I live in a typical suburban neighborhood north of Philadelphia. Lots of noise but I am receiving 160-10meter clearly -110 -120 noise floor.?
still some things to try, may put the loop through the bead roller to stiffen it up some. Have a good day?

thanks.?
John.?

?