Lightweight Coil for POTA, SOTA, IOTA and More
This loading coil is perfect for a day on the air from your favorite park, a weekend camping, or even hiking. Just add your favorite 17′ or 18′ whip antenna, a base and a few radials, and you can work the world on 40 meters (7 MHz).
If you like working Parks On The Air, Summits On The Air or other portable ham radio activities but are missing out on 40 meters, then this coil is what you need to make your activations even more fun. Weighing in at just 15.1 ounces, this coil won’t add a lot of weight to your backpack. There’s no clamp to adjust to find the sweet spot. This coil has a wide bandwidth with a SWR below 1.5 across nearly the entire 40M band. And when you’re ready to switch bands, simply connect the bypass wire to remove the coil from your antenna system. No need to stop and remove the coil and then reattach the whip. NOTE: The blue bypass wire on the side of the coil should be disconnected to operate on 40 meters.
See photos for SWR across the 7 MHz 40 meter band. Your results may vary based on number of radials you use, your soil conditions, your particular whip antenna, etc. In our testing, we used a 17.4′ whip that was extended 13′ 1.5″. This was the sweet spot for this coil and whip combination. For radials, we used three 18 AWG wires at 12′ in length and one 18 AWG wire at 25′ in length that were lying on the ground. If you’re using elevated radials, your radials should be 1/4 wavelength for best results.
Coil is made with schedule 40 PVC and 16 AWG insulated stranded copper wire.
This listing does NOT include ground radials, a mount or a whip.
Recommended power limits: 100 watts SSB, 75 watts CW and 50 watts on digital modes.
There are two options available:
- 3/8″x24 fitting for MFJ and similar whips with a standard 3/8×24 antenna mount on the bottom of the whip.
- M10x1.5 fitting for imported whips that have a M10/10mm metric stud on the bottom of the whip.
This coil is custom made in the USA, in the Arkansas River Valley by volunteers from the Two Rivers Amateur Radio Group. Each coil is machined and assembled by hand to ensure consistency in build quality and on-air performance of your coil.