NØEQ "Trashbeam"
... 2m Yagi from recycled discards
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A 2m, 6 element beam built from neighborhood garbage! Here in Phoenix, we have a wonderful program called "Bulk Trash Week". Every 3 months, Phoenicians are encouraged to place their large, bulky discards at curbside for one week. Scavengers (that's me) are encouraged to rummage through the discards and to take anything that they think they can use. After the week of "rummaging" the city trash trucks come around and pick up all the remaining discards. End result, we all get to get rid of our old, dead appliances, building materials and furniture, the landfills are a little less crowded, AND the desert wilderness gets a little LESS filled up with discarded couches and refrigerators. This 2m, 6 element Yagi antenna was built entirely from discarded items that I found during "bulk trash week" |
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Boom, Elements, Mast... all recycled discards The boom is a recycled fiberglass telescopic tree pruning pole. Originally yellow, it's now my signature camo paint scheme. |
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Reflector, driven element and directors as well as all the hardware, clamps, nuts, bolts, even the mast, are recycled from a TV antenna that someone threw out. Recycling the aluminum elements was simple. I drilled out the existing rivets that held the original TV antenna together. That left me with several tubular aluminum elements, several aluminum hold down clamps and a bunch of scrap elements to use to reinforce the mounting joints. |
 
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Gamma Match from recycled parts The gamma match was made from the same TV antenna parts. The outer sleeve of the gamma is a piece of TV antenna element. The inner concuctor of the gamma capacitor is a section of what was originally the phasing wire on the TV antenna. The dialectric is a piece of rubber fuel line. That rubber hose wasn't part of the TV antenna, but it was a 'throwaway' that I rescued from someone's bulk trash. Even the SO239 is a salvage from a discarded CB radio. |
 
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Testing the Trashbeam for SWR, reactance, impedance, resonance The tripod stand I use for testing is a piece that someone discarded as trash. I slid the mast (recycled of course) into the tripod stand, connected a length of (recycled) RG58 coax, connected and powered up the MFJ analyzer. I initially guessed at the gamma match measurements. Initial SWR was greater than 2:1. So I guessed again, moved the slider clamp a little bit and read the meter again. |
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Here's the readings from the MFJ analyzer... From 144 to 148 MHz SWR is - Best case 1.1:1 Worst case 1.3:1 Reactance is - Best case 4 Worst case 10 I try and shoot for a max reactance of 10 for any antenna. I've achieved that with the Trashbeam Impedance is - Highest at 62 ohms Lowest at 43 ohms. Prior to my applying the camo paint, I was actually able to achieve a perfect match. Impedance was 52 ohms Reactance was 0 ohms SWR was 1:1 Applying the truck bed liner coating followed by the camo paint changed the resonance/capacitance of the Trashbeam a tiny bit. But it's stil well within limits. The spray on truck bed liner stuff and the three colors of spray paint for the camo effect, were the only part of this antenna that cost anything. They were left over from previous projects so I didn't have to go out and buy new paint. But I did spend actual money on paint at one point in time. Everything else about this antenna was 100% free for the taking from neighborhood bulk trash day. |
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