ANTENTOP- 01- 2017 # 021

The GRASSWIRE:
Another Approach to Hidden HF Antennas

The GRASSWIRE:
Another Approach to Hidden HF Antennas

 The article is an AntenTop Magazine variant of Chapter 7 from K3MT book "HF Antenna Topics."

Deed restrictions got you down? Neighbors intimidating your tower plans? Need a really easy, portable HF antenna? Then the Grasswire may be the answer! Virtually invisible, lightweight, and compact (you can carry one in your hip pocket), this antenna works! I've used one in various installations for more than 10 years.

Read on - and listen to the "experts" telling you that this is hogwash, that an antenna like this can't work. But it does. And true experts, who have taken a decade or more to come to grips with the intricacies of Maxwell's Math, know why.

Grasswires will not out-perform a yagi, or a decent dipole up a half wavelength. Not in gain or signal strength, at least. But they do survive ice and wind storms, and are practically immune to lightning. And they don't need a large tower or tall support. I deploy one from my hip pocket at times - the balun to match it is larger than the antenna!

 The Grasswire - In Brief

 What is it? Put simply, it's an end-fed, longwire antenna that is laid right on the grass. Hence the name. Look familiar? Yup! It's a very low beverage antenna...

 My first Grasswire, built in the summer of 1988 was just 204' of #22 AWG magnet wire laid along the propertyline, anywhere from 1" to 6" above the ground.

K3MT's HF ANTENNA TOPICS

For info on availability, please email to

k3mt@arrl.net

Figure 1 shows plan and elevation views of a typical installation.

An 8' ground rod and optional counterpoise wires are shown. The counterpoise is a 40' wire, center tapped. Use it or the ground rod: you don't need both.

These antennas are largely resistive, with values ranging from 150 to 500 ohms or so on average ground. I've used them successfully on the soils northwest of Washington, DC, on the sandy soils of the Cape Canaveral, Florida area, in the rocky, shale soils of the

mountains in Somerset county, PA, and on river bottomland of Allegheny County, PA. One was used with great success by K3MT/VP9 in Southampton, Bermuda - the object of nightly pileups on 30 m CW for four nights.

Reflection and the Brewster Angle

The skeptic in you will doubt that such low antennas can work. After all, its image in the ground radiates and cancels out all radiation. True - if the ground is perfect. But nothing is perfect!

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