VHF 2m band Moxon beam antenna, backback foldable

thingiverse

Work in progress - Changelog: 2019-06-20: Recent tests: Use a slightly thicker wire (1 mm²) for better bandwidth and easier tuning 2019-05-05: Slightly shortend the caps to reduce printing time. 2019-04-12: Coax solder connection very fragile. Added T-piece to protect it Lightweight and portable Moxon beam antenna for ham radio (amateur radio) for the 2m band (145 MHz +/-). Usecase for SOTA, GMA or contesting on mountains. Print: 1x Center 1x BNC plate / or the angled one (take this if you will use it both vertical and horizontal) 4x Endcap 2x Spacer 1x coax2wire protector Lenght calculation done with Moxon Rectangle Generator: https://www.ac6la.com/moxgen1.html Additional components needed: - 4 pieces of 381 mm lenght and diameter 4 mm glass fibre rods/tubes (non-conductive material like plastic tube e.g. PVC. my prototype used bamboo sticks from the garden center). They will need to be cut to the right lenght to match the rectangle in the size given in dimension "A" and "E" in the calculation tool (see screenshot attached) Sources: RC supply shops, Kite shop - About 2m of antenna wire 0.3mm² total conductor CSA (approx. 22awg). Cut the driver and reflector segments according to given dimensions. (For other frequencies and wire diameters recalculate and adjust as needed.) - About 0.75 meter of thin 50 Ohm coax (like RG188 or RG316) for the common mode choke and connection to antenna wire - BNC bulkhead connector (solder or crimp) Other infos: The BNC plate is glued with super glue. The 4 holes are undersized and should be drilled to a diameter to have a good fit to the rods/sticks. This is for the transport position. The coax2wire protector will mechanically stabilize the fragile solder point on the coax. Solder, test (antenna analyser) and if everything works fine fill with superglue or epoxy. The two spacers are for the air gap between the driving element (where the coax is connected) and the reflector. Again for other wire diameters the gap needs to be adopted. And of course a telescope pole or fishing pole (glass fibre and not carbon) for mounting it is needed. 8 mm holes for horizontal and vertical polarization mounting positions. Video how to fold it for transport: https://www.youtube.com/watch?v=b9s1-g-zy8w