To celebrate my new licensed amateur status, I decided to build an antenna for my new radio.
The radio is dual band (2 meter/70cm), but I decided to start slowly and make an antenna for just the 144MHz (2 meter) band, since that's the one I'll be using most. I found the specs here (part of a compendium) I used the rest of the compendium as well as other reference material, particularly this video by +Martin Lorton,
I enlisted the help of my brother-in-law, who has skills (see the generator house). In the interest of using what we (he) had, we used a copper plate instead of aluminum, and 10-gauge wire instead of welding rods for the radials. There may be a galvanic action problem, but we'll see.
1. SO-239 chassis connector https://www.radioshack.com/products/so-239-coaxial-socket?variant=5717635205
2. 6” SO-239 to SMA female jumper http://www.amazon.com/gp/product/B00COKNKS8?psc=1&redirect=true&ref_=oh_aui_detailpage_o00_s01
3. 18’ coax with PL-259 connectors http://www.amazon.com/gp/product/B001JT0CGI?psc=1&redirect=true&ref_=oh_aui_detailpage_o00_s01
4. 4-40 machine screws, washers, and lock nuts (4 ea)
5. 12 AWG wire (19 5/16” + loop, 4 x 20 3/16 +)
6. Copper plate (~6” square)
7. PVC pipe for stand
- drilled a 5/8" hole and four small holes (for the 1/2" 4-40 machine screws) in the copper plate
- attached the SO-239 to the plate with the machine screws
- cut the wires to length (4x#10, 1x#12, 19")
- bent the radials to 45 degrees, 4 inches from one end
- soldered (instead of screwed) the radials to the copper plate
- soldered the #12 wire to the center pin of the SO-239
- connected the cables to the antenna, each other, and the radio
- on the air (not yet...I need to hear activity in order to know what's up)
We found an old Archer 21-256 CB tuner (over 40 years old). It claims to cover 2-175MHz. Just for drill, I cleaned it up and connected. It showed my SWR was way off. I tried bending the radials up, and it got worse. I bent them down, not quite to vertical, and I got it to 1,2. I have no idea how accurate the device is or how effectively I used it, but I used it.
I have not raised anyone, with the antenna, but I had the same issue without it. This morning I heard 2 people on a local repeater and when they finished I asked if they could hear me. I had a nice conversation with one, so my radio transmits. Now I just have to test the antenna.