We have received many questions about our 80m EFHW (end fed half wave) antenna, so here are the details:
This is an antenna you can put together yourself and get on 80 through 10m without a tuner, 60m excluded. It works well on 80, 40, 30, 20, 17, 15, 12 and 10m.
So far we’ve worked 186 countries, 50 states, and all 7 continents SSB w/100 watts on this exact antenna
Using a transmatch, you can probably transmit on 160, 60 and 6m with less than 2:1 SWR. We have not tried this yet, but the antenna as built does hear very well on those bands. The transformer is rated for ~100w SSB or 50w CW at 50% duty cycle so be mindful of your power
This antenna is basically copied from a portable design by Thomas KE8OWX with minor changes for a permanent install, full credit to him for getting us started
Photos:
Parts list / links:
- Transformer: 64:1 variable UNUN w/ 100pf 3 kv capacitor & PL-259 connector **
- Box: 3.94 x 2.68 x 1.97 inch (100X68X50mm) (Pack of 2)
- Wire: DXE Premium 14 AWG antenna wire, cut @ ~137 ft long
- Insulator: DXE Wire Antenna end insulators
- Insulator anchor line: Military surplus paracord, length as needed, ends whipped & melted
- SS (preferred) or zinc plated hardware as pictured from your local hardware store
**The seller out of Bakersfield, CA is John KG6ZBN, an Extra class amateur radio operator who ships quality products very quickly. He’s a great guy with excellent communication: deal with him direct or through Ebay
Notes:
- The knot attaching the wire to the eye on the top is a modified Perfection Loop
- Be sure to leave enough slack between the eye bolt and the termination bolt for strain relief
- Drill a 1/16″ hole in the bottom of the box for ventilation/drainage
- Solder the capacitor to the center conductor
- No counterpoise wire necessary: the shield of the coax serves as the counterpoise. For this reason, leave at least 20 feet of straight coax running away from the transformer
- Use the second box in the package for a junction box where the coax enters the structure. Form a drip loop before the coax enters the box
- The eye bolt can be used for hoisting the transformer in portable applications using non-conductive methods
- The long wire can be installed in a straight horizontal, sloped, inverted V, or inverted L configuration. Just get it as high as possible. Buildings, trees and pulleys are your friends
- Ground the shield of the coax just before it comes into the structure with a Polyphaser or equivalent
- Like most antennas, you must tune this antenna in situ with an analyzer/nanoVNA for optimal SWR on the desired bands. We suggest starting with achieving minimal SWR @ 3.750 MHz and going from there. Simply fold the wire back on itself using the locking insulator until acceptable performance is reached. The final length should be between 135 to 133 feet. Connect the analyzer at the end of the coax that would feed into the radio so you’re seeing what the radio would see
This is a fairly simple yet versatile antenna. When you make your first DX contact on a wire antenna that you put together, you’ll have a smile on your face!