Thursday, May 21, 2020


New Ham Antenna Launcher

Shelton 3.1 lite - Shooting position,  the pill vial is the steel stinker storage
Gorilla tape covers the 3 inch angle bracket leg that is screwed into the front of the Slingshot handle.
Gorilla tape also covers the leg of angle bracket zip tied to the pill vial and the Zebco 404 reel.

I 've tried several antenna launching systems over the years.  I think the first method was to put a handful of gravel in an orphaned nylon dress sock. Tie it on a string. Swing it around a few times (screaming like a chicken) and cast it into the trees. The cons of this method is you need to wear leather gloves to prevent rope burns, somewhat inaccurate and even a nylon dress sock hangs up in a pine tree sometimes.

Next I tried a collapsible backpack rod & reel with a 1 oz torpedo sinker. The reel was a Zebco 202. I spooled 20# test mono line until the reel was full. I had problems with the tall pines tress. The sinker would wind up just out of reach overhead, I would have to remove the line from the reel. Tie extra mono to allow me to reach the sinker. Remove the stinker, tie on the light hauling line. Pull the extra mono hand over hand back over the storage spool. until I reach the end that goes into the Zebco 202, retie the line onto the reel and crank the mono line all in. Finally getting to the haul line to actually raise the antenna. This system was also prone to having the sinker spin around a branch several times making retrieval impossible.

I broken down and purchased a JARC antenna launcher kit. The kit had all the PVC pieces to construct an air cannon launcher and two "pucks" to attach the mono to. I had to provide an air pump and a reel. I knew that the Zebco 202 was too lacking in line capacity.

I wound up buying a Zebco 888 preloaded with 110 yards of #20 test. I now could reach over those 100'+ tall trees my only concern was losing one of my two "pucks". The only time this system failed was when I broke the air pump and had to run into town to pick up a $12 replacement. 

After that failure and the fact that the air launcher was bulky and cumbersome. I decided to have a backup system that was more pack friendly if I wanted to do POTA or portable operating.

I remember George Thomas, W5JDX of AmateurLogic.tv and Ham Nation using a slingshot for his early ARRL field day ALtv videos. After a while I stumbled on N0KTZ "Rusty" youtube video that shows how he builds his "Shelton 3.0 Magnum" slingshot launcher which inspired my build.  https://youtu.be/ZtJvTQ2oogQ

    
My Three Antenna Launch systems

Screwdriver, Air gauge, Air Pump, "Pucks", 5 spools of cords
Air Launcher's large air chamber with ball valve
Air Launcher's Barrel with Zebco 888 attached
Backpack rod with Zebco 202 attached, rod holder
Torpedo sinkers, Snap swivels, 2 green Kite reels with 300' 100# line
Shelton 3.1 lite Slingshot with Zebco 404 and pill vial attached
4 one oz steel bass weights painted (fits in pill vial)
4 packs extra steel bass weights
MISC:
zip ties, 3in angle bracket, snips, extra mono line, gorilla tape
Storage box for Air Launcher
aerosol paint cans

I departed somewhat from N0KTZ bill of materials. He used PVC irrigation components brought from a "Big Box" stores. I used a 3 inch angle bracket and parts obtained thru my local Walmart.  I am calling my build the "Shelton 3.1 lite". 

My parts list follows:
  • Daisy F16 Slingshot                                                      <$5 USD
  • Zebco 404 spincast reel (w/ 75 yds #20 test mono)      <$10 USD
  • 1 Angle Bracket 3 inch (comes 4 per pack w/screws)    <$3 USD
  • Walmart Rx Pill Vial  (to hold sinkers)                          Free w/ Rx
  • 3 zip ties                                                                          had on hand
  • Gorilla Tape                                                                    had on hand
  • 2 packs Eagle Claw Steel Bass Casting Sinkers 1oz.   <$4 for both packs
So my total was less than $25 USD, while at Walmart I bought extra steel bass casting stinkers and a sand rod holder to hold my kite reel to unspool while I'm hauling the line back over the tree from the other side.

Shelton 3.1 lite - Line retrieval made easier by holding the handle with the slingshot upside down