Posts Tagged ‘Gizmo’
Portable, Ground Plane for 2 Meters made with BNC antennas
that you can ‘take down’
Its a compact ground plane antenna for portable use!
This antenna is built on a 2 inch washer. Holes were drilled in the washer to accommodate 4 radials. The center hole for the BNC to BNC connector was already there, but had to be reamed out. This (male to male) connector is where the coax from the radio is attached on the bottom of the washer. It also serves to hold (the center radiator element)!
(Note: The radiator, in the center, needs to attach to a BNC MALE connector, the cable from the radio also needs a BNC MALE connector. I used a male to male adapter for this purpose. It didn’t fit tightly so I used an old bike inner tube to cut a small spacer for taking up the slack. I’d have used a metal washer for ‘fitting’ the adapter, but I had already make 3 trips to the hardware store, so I used what I had)
Gizmo Portable Antenna
without the cover
I used BNC female connectors from, Digikey, a good source for components! The center post of this connector is shorted to the ‘shell side’ to provide a ground plane with all the radials!
The 24 inch antennas from China were purchased on Ebay! CHEAP! The 2 inch washer is from the local hardware store. Everything fits on this washer, a 2 inch space, but the center coax is tedious to attach with all the radials in place, especially if you have big fingers.
The Cap is from a spice bottle!
I live alone so it was not a problem! LOL
I love to use things for which they were never intended! This spice bottle cap is a good example of this. At this point, I’m not sure if I’ll seal it to the top BNC antenna radiator element or not? If I seal it (with hot glue, maybe) , the cap becomes permanently attached to the radiator element, and would be difficult if not impossible to remove. The whole idea here is to use this antenna as an impromptu portable antenna!
A tie wrap is used to ‘hang’ the antenna. Its hanging from a hook on my porch at the condo. I put 50 watts into it to get a repeater 10 miles away. SWR was 1:1 This is a portable antenna! Its not meant to be a permanent one. If you have ever needed a 2 meter antenna that you can pull up into a tree with a string or rope, this is it! Hauling it up 40 or 50 feet on a rope will get you better results than at ground level.
There is a joke that says, have you ever seen a golfer with only 1 club? Ham radio antennas are in the same category as golf clubs. You just can’t have too many!
All the elements can be removed for easy storage and transport, (radials as well as the vertical element)! I’m sure some clever ham will come up with a suitable case for this entire assembly. If I had one of those nifty clear plastic shipping tubes, I’d store in that! I’ll be on the lookout for one!