Portable Yagi Uda Antenna Parts
Description
Portable Yagi Uda Parts ================== I used these parts to build a Yagi Uda based on M0UKD's design, but these bits can be adapted to any design. M0UKD design is published at: https://m0ukd.com/homebrew/antennas/144mhz-2m-portable-yagi-vhf-beam-antenna/ Updates ---------------- * Updated the 3mf file for the driven element box and parts. Support enforcers were not working on one of the clips. This now slices correctly and reflects how i was able to print the parts successfully. * Added a sleeve to allow the boom to be split- very handy for packing it in a fishing rod bag. Need a M3x30mm machine screw and nylock nut to retain the sleeve on one half of the boom. * Added end caps for the boom- to prevent it getting damaged. Other Parts Required ---------------- * Boom: 15mm square x 2mm WT aluminium box section. * Elements: 6mm OD x 1mm WT aluminium tube * Ferrite: I used a FT140-43, but there are many ways to configure the feedpoint in a yagi. * Coax: Short length of RG316 for the turns around the toroid. * Ring terminals & M3x8mm machine screws to attach feedline to driven element. * BNC female panel mount- i think i got these on eBay * Mast: i'm using a DX Commander Travel Edition telescopic fiberglass pole, but there are many options here- SOTABeams have a bunch. Mast mount is sized to fit half way down the 7th section from the bottom at an elevation of around 3.75m. I got my aluminium parts from Aluminium Warehouse in the UK. Reasonable pricing and delivery. https://www.aluminiumwarehouse.co.uk Ferite and RG316 were purchased from Ham Goodies website. https://www.hamgoodies.co.uk Mast Options: DX Commander: https://www.m0mcx.co.uk SOTA Beams: https://www.sotabeams.co.uk Print Notes --------- I printed all parts except the element end caps in PETG, 0.2mm layer height, 15% infill. 1. 5x element clips. No supports needed. Orient with the element hole parallel to the build plate. This squishes the hole a little, but will provide a good fit to the elements themselves. 2. 1x DE Box, 1x DE Box Lid. and 2x DE Box Clips. Orient the box bottom and the lid top surfaces onto the build plate. I used supports on the DE Box to ensure the pentagon shaped holes were printed accurately. For the clips, orient the same as the other clips, but with the pentagon shaped pieces facing up to it's accurate. Supports are necessary on these. The cross for the toroid will need a bit of trimming to fit. Only superglue the clips in when you're doing final assembly. 3. 1x Boom Mount. Print with the square hole for the boom oriented vertically to ensure it is accurate. The build plate end of the boom hole may need a bit of trimming due to the old elephants foot effect. This will need supports. I tried using support enforcers and it was a nightmare to remove. But not bad at all when i let Prusa Slicer auto detect and build them. 4. 12x Element End Caps. If you value your eyes. I printed these in red PLA for visibility. These were a late addition after a few close calls during assembly. Build Notes ------------- I printed all the parts and test fitted with my hardware, tweaked and then re-printed as required. I cut all passive elements exactly as per MOUKD's design, but left the driven element a little long (~12mm long) to allow for final tuning when the antenna was up in the air. Clean out 6mm holes as required, and stop elements from sliding using a little electrical tape on the elements. Scribe marks on the boom for alignment of the elements along its length. For the feed point connections I drilled and tapped an M3 hole through each driven element. Also marked the bottom of the box behind this hole with an awl to allow the screw to bite into the box and secure the element properly. The picture inside the DE box explains all of this though. Testing Notes ------------- Tested using an FT991A on FM, vertical polarisation. 20m M&P Airborne 5 coax (2.22dB loss @144MHz). Test #1: Pointing directly at it, opened a 23km distant repeater using 5W, carrier heard at S9+50dB. Turned to the reciprocal azimuth, carrier heard at only S7. Test #2: Opened a 46km distant repeater using 5W, carrier heard at S9. Turned to the reciprocal azimuth, carrier barely heard S0. Tried to open this repeater while pointing away from it, required 20W to open it. Based on my coax losses, and the stated antenna gain (11.46dBi) i was pushing ~168W at this time. Results: there is definitely some front to back gain on this one! Many thanks to M0UKD for his build guide- without it i would have still been thinking how to go about building this!
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