Friday, March 8, 2019

Is this the world's worst HF antenna?

Yesterday we discussed the highest antenna you can practically erect - a wire supported by a kite. Today's topic is the opposite. Not only low in height but low in efficiency as well.  The only reason why you'd want to make one is so you can tell others you've done it.

I'm talking about the lowest of the low here - an end-fed wire on the ground. On transmit it's almost a dead loss. Like short circuiting most of your signal to earth. On receive it's a different story. That's because we're after not so much signal strength but signal to noise ratio. Here a new antenna that reduces the desired signal by 10 dB but undesired signals and noise by 15 dB is a winner due to an overall improvement in reception quality.

Enjoy these articles and videos on what antennas on the ground can and can't do.

* KK5JY's loop on ground antenna

* 40m SSB with a wire antenna along the ground.

* HF WSPR with a wire antenna along the ground.

PS: For some much better antennas try some from Hand-carried QRP Antennas. Available in electronic and paperback form (some countries) this well-reviewed book is a popular read amongst hams who go portable.

 Link to find out more about Hand Carried QRP Antennas

1 comment:

  1. No Peter, this isn't the world's worst HF antenna! Admittedly, a dipole for 20m and above will be useless if laid on the ground. But, on the lower bands, an end-fed wire at least one wavelength long will radiate at a low angle off it's far end. It will be lossy. A 100W signal will be down at QRP level but if a stealth antenna is called for even a highly directional QRP signal is useful. Note that shorter wires will radiate straight up and NVIS rules will apply. I have experimented with ground wire antennas and have successfully QSOd with them. K3MT is famous for his very successful "grasswire" antenna in Bermuda. It certainly wouldn't be my first choice, but a full wave wire on the ground can get the job done in a pinch.
    John, VA3KOT


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