Topband: Historical note: Radial Depth

[Donald Chester]

I can appreciate reasons why MW BC stations and LW transmitter sites would bury their radials deeply, plus they could be expected to have the equipment and deep pockets to do it.  But in my opinion, anything below a few inches is unrealistic for the vast majority of hams, and in practically any case, unnecessary.

My radial system consists of 120 quarter wave wires (16,000 ft in all).  Overkill for amateur purposes I know, but I stumbled upon an extraordinarily good deal for a big  spool of #12 bare soft-drawn while living out-of-state back in 1974. When I finally got round to building the radial system in 1983, I fabricated a homebrew plough, attached to a walk-along garden tractor for laying them.  With one helper, we laid the whole radial field in four days.  They average 2-4 inches in the ground.  Our red clay soil here is very benign: PH neutral and the minerals don't corrode copper too much.  Occasionally, I'll dig down to randomly inspect a radial and even to-day the wire looks virtually intact other than for a greyish patina.  

A copper thief would have a VERY hard time pulling up the wire.  I had to temporarily move a radial out of the way a few years ago for another construction project, and it was all but impossible to pull the wire up though the clay soil and sod.  I ended up manually slitting the ground with a spade the day following a good rain, in order to pull up the wire without stretching or breaking it; that was more  difficult than manually laying radials using a hand tool.

The writer of the article in the antenna book most likely just copied directly from a broadcast or commercial communications manual without giving serious thought to the different situation amateur practice would present. I suspect very few hams attempted substantial 160m radial systems during the waning days of the Great Depression before the  war broke out. Probably because of the WWII shut-down and the uncertainty of the 160m band and LORAN following the war, this wasn't revisited and corrected until years afterwards.

Don k4kyv