Link End Fed Half Wave Antenna and Tuner for SOTA

QRP Multi-band EFHW antenna for SOTA

My take on a QRP EFHW inverted V antenna designed for use on three amateur radio bands 15m, 20m, and 40m.

From the feed point the total length is 20.1 metres (65.94 feet).

Links are inserted at 6.84 metres (21 MHz) and 10.05 metres (14 MHz).  For operation on 7 MHz close both links.  The counterpoise wire is 1.5 metres long or 0.05 of a wavelength on 40m.  The coax feedline between the EFHW tuner and the radio is 2 metres long.

Reference site:  Steve Yates AA5TB  The End Fed Half Wave Antenna

Link EFHW for SOTA

Link EFHW antenna for SOTA

Antenna winder: TET-Emtron (Perth), Squid Pole: Haverford (Sydney)

EFHW antenna 15/20/40 metres and winder

EFHW antenna 15/20/40 metres and winder.

nylon dog-bone end insulator

nylon dog-bone end insulator

squid pole center support

perspex squid pole center support

EFHW Antenna

EFHW antenna components

Link Insulator:  30mm length of 6mm fibreglass rod, salvaged from a UHF mobile antenna

Connectors: automotive spade connector male and female pair

Clamps: small black cable ties UV resistant

dipole link closed

spade link closed

dipole link open

spade link open

link close up

close up – automotive spade link

Circuit – Impedance Matching unit rated at 15 watts

QRP EFHW Impedance Matching Circuit

QRP EFHW Impedance Matching Circuit

EFHW matcher

EFHW match circuit

Inside the box

Inside the box

close up

close up – T80-2 Toroid Permeability = 10, 25 turns tapped at 3 and 4 turns.  266 pf poly variable capacitor from EMTECH

Coax feed line between the impedance matching unit and the radio is a 2 metre length of RG58AU.

The EFHW antenna is a popular choice among VK SOTA activators.
Other EFHW antenna designs by VK SOTA activators:

16 thoughts on “Link End Fed Half Wave Antenna and Tuner for SOTA

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  3. Hi Andrew
    I am using these 2mm-Heavy-Duty-Golden-Bullet-Connector-Plug-for-RC-Helicopters conenctors i got on ebay. They are the same as on the PackTenna antennas and i find they may make a better connection than the ones you are using. Just an idea

    • Good idea, I suppose the banana plus are easy to ‘plug and unplug’. I like the auto spade connector positive ‘lock’ but yes they are a little fiddly. Good thought for others to try out.
      73, Andrew

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