I’ve been making my own 5.8 antennas for a few months now. Big thank you to David at RCExplorer.se for his how-to and online calculator for antenna element length. I mostly followed his instructions, but modified the antenna element geometry so each element has 10mm to solder directly to the coax braid. Also, thanks to Bruce at RC Model Reviews for his how-to video!
I designed these antennas for the frequency I fly on, Boscam7 5.9ghz. My friendly RF Engineering colleague helped me measure return loss on a couple of my antennas and also compared them to the popular Immersion Fatshark Spironet antennas. The Spironets came in at 13db as advertised. I was surprised that mine measured 15db! Wow. In real testing, my antennas do perform well, even behind trees at Baylands park.
- cheap RG402 coax cable from ebay
- antenna elements are made from telephone wire which can be found at Home Depot by the foot
- coax connectors are regular SMA, solder-on for RG402 coax, purchased from Ebay
- The coax cable braid is very brittle after it’s been soldered. I had several antennas break where the shielding meets the SMA connector. Fix? Add hot glue at this location and heat shrink over it. Problem solved, antennas have been rock solid since then.
- I like to cut the coax wire length to 1*lambda. This creates a shorter antenna that will be less likely to snag an air-gate or tree branch.