Portable End Fed Half Wave (EFHW) antenna kit BNC SOTA POTA
Our BNC EFHW Kit contains everything you need to get up and running and on the air. Wire is supplied so you will be able to use 40m, 20m, 15m and 10m bands without the need to purchase anything else.
It's tough, lightweight, and portable. The PCB when built is only 104 grams or 3.7 ounces. A completed antenna (T140-43) with wire approximately 183 grams or 6.5 ounces.
This is an ideal antenna for SOTA or POTA activations, either hung from tree limb, or a fibreglass pole. As a verticle, inverted V or sloper.
The PCB is finished in white. It has wide tracks and supports 100w+ SSB and 25w+ CW/Data depending on the core selected. Additionally, there is a connection for a ground or counterpoise wire. Although the antenna will work without one using your coax as a counterpoise.
The kit has been designed to allow for two different cores sizes.
Core ratings SSB/CW-Data
Fair Rite T140-43 (5943002701) core will handle 100w SSB/25w CW & Data, 80-10m bands.
Fair-Rite 2643251002 Mix 43 - 1.54" by .875" a very popular core for medium power applications 300w SSB/150w CW & Data 80-10m bands.
The Kit contains.
Core of your choice, see options.
M5 & M3 fittings including bolts, nuts and wing nut and solder tab
100pf TDK capacitor
Approx. 1.5m enamelled copper wire
Approx. 21.5m of SOTA wire, DEF 61-12 Part 6 type 2, 23AWG, tinned annealed copper conductor, .22mm² 7/0.2mm conductor, 1KV PVC Insulation
Build instructions are here.
LB0FI Norwegian Hamventures, in no way associated with Radio-Stuff.com
Link to youtube video build here.
Pota activation youtube video here.
Please check your SWR before using the antenna to ensure you have a good match with your transceiver before use. The wire supplied is normally longer than you need, and you may need to cut a considerable amount off the wire before the antenna becomes resonant.
But start long and cut small pieces of wire off the overall length.If you want to use 40m, 20m, 15m and 10m. Tune the antenna to 7.0mhz.
The Fair-Rite Mix 43 - 1.54" by .875" core should be wound as a 56:1 transformer for maximum efficiency.
This is a perfect antenna to use with a kite, with room to run a static bleed off resistor to ground.
For prolonged use in bad weather, we would recommend waterproofing all electrical connections with liquid electrical tape or clear nail varnish.