Shooting Antennas

 

Rich Bonkowski, W3HWJ

 

In over 40 years of ham radio operation in four different states, I have had my share of experiences in erecting wire antennas.  Between moving to new homes, temporary apartments, and field day operations, I’ve probably put up over a hundred antennas.  The goals are always the same, however.

 

·         Get the antenna as high up as possible

·         Keep it away from utility lines

·         Make it as innocuous as possible, so the neighbors don’t revolt

 

Like many of you, I’ve used weighted lines, slingshots, ladders, sticks, and neighborhood kids with bows and arrows to string my dipoles up from tree limbs.  Back in the middle 1980’s when I lived on a large lot in rural Western Pennsylvania, I got a brilliant idea for securing the end ropes of a full-sized 160-meter half wave dipole.

 

Having seen various movies and news clips about whaling, I remembered the harpoon guns the whalers used.  You should also remember the smaller harpoon gun used in the movie “Jaws.”  I reasoned that I could make a home-brew “harpoon” from a 3/8-inch wooden dowel about 24 inches long.  As I was also an avid shooter, I had a single-shot 45/70 rifle (same caliber as used by Custer’s troops at Little Big Horn) which could easily accommodate the 3/8-inch dowel in its barrel.  A homemade blank cartridge and some fishing line… it had to work!

 

Unfortunately, there is more to designing a harpoon than meets the eye.  I did get it to launch successfully, and to travel 50 yards or more at pretty high speed.  Wooden dowels, though, aren’t harpoons.  They aren’t completely straight and the attached line makes them hook or slice.  Because I was aiming for a crook high up in a maple tree, I wasted many blanks trying to figure out where to set my sights.  Some promising shots ended in disaster, as the line got caught in small branches and broke, due to the high speed of my “harpoon.”  My last shot seemed “dead on.”  Unfortunately, the dowel struck the tree trunk directly and shattered itself into a dozen pieces.  I gave up in disgust, made more stinging by the looks I got from my wife, who was sure I was some kind of nut!

 

Well, last week, I was vindicated.  In an old National Rifleman Magazine from the 1970s, there was an article about “Antenna Erecting Blanks.”  My idea wasn’t so crazy, because in May, 1944, the Army actually commissioned Frankford Arsenal to develop a 30-06 blank cartridge designated “T61” for use in launching wire antennas.  The Aircraft Radio Laboratory wanted these cartridges for use in field installation of the AN/CRN-1 aircraft beacon equipment. Some further research on the Internet indicates these may also have been used with the AR/CRN-6 systems.

 

The Army ordered 16,500 of these cartridges, which were loaded with a mix of black powder and standard smokeless powder.  They were shipped to the Air Technical Services Command in Dayton toward the end of World War II.  These are less than half the length of the standard 30-06 case, and were crimped to seal in the powder.  I would imagine that they were single loaded into the breech of an M-1 Garand and the antenna line was launched, much like a rifle grenade. The fact that they used black powder must have meant that a 100% load of smokeless develops too much velocity (as I later found out).   I haven’t been able to find any information on what sort of hardware went down the rifle barrel, but I’ll bet it wasn’t much different from my antenna harpoon! 

 

I won’t try to resurrect the harpoon launcher again.  Weighted lines and kids with slingshots seem to work just fine.  But, maybe that’s because I’ve been willing to live with lower elevation antennas as I get older?

 

References:

“Antenna Erecting Blank.”  American Rifleman Magazine. Published by the National Rifle Association.  July, 1973. 

 

Internet:  http://guns.connect.fi/gow/QA6.html  "Cartridges, Antenna Erecting", by: P. T. Kekkonen

 

Internet: http://www.netside.com/~lcoble/dir7/usammo.txt  T61: Cartridge, Antenna Erecting

 


Biographical notes:

Rich Bonkowski was first licensed as KN9VLQ in 1960.  He has an Advanced Class license and a BS degree in electrical engineering.  He worked in engineering and marketing for Westinghouse, Siliconix, and JDS Uniphase until his retirement in 2000. He has six US patents and several more pending in Europe.  Rich’s current interests include vintage radio, especially home-brew regenerative sets, Italian and German language lessons, and enjoying the excellent wines made near his QTH in Sonoma County, California.

 

This article was originally published in Electric Radio Magazine,  Number 149. October 2001. Page 14.  My thanks to the editor of Electric Radio for allowing me to post this version.