Whilst my delta for 20m can put up with gusts up to about 60mph, sometimes the wind does easily exceed this level - up to 85mph - and sustained winds of 48mph for hours or even days on end are common.
I recently played with a phased, two element vertical system for 20m. I didn't find it a very practical system, and it was rarely better than my delta loop.
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| 1/4 wave of vertical element, 1/4 wave of radials. Easy! |
So, I cut one antenna out of the equation and left one standing. A 7 metre fishing pole is ideal for a 20m vertical, being 5.03m or thereabouts in length, thus raising the feed point and radials to a good 1.5m above ground.
I only use two radials because more become a big headache in a family garden, and that my ground is excellent and that two radials are, in fact, more than adequate for a quarter wave vertical! One radial is more-or-less parallel to the local ground, the other slopes 5 degrees downhill; QST magazine reports this to be the best configuration in terms of gain, though this is marginal, to say the least.
You can get more involved in shorter-than-quarter-lambda radials if you read Les Moxon's 'HF Antennas for All Locations'. Suffice it to say that quarter-wave radials do, however, work!
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| KI0WN enjoying the very low angle radiation of a vertical at the beach (keep it very close to the surf!) |
The result? There's certainly more noise on the vertical than the delta, but for all but the very weakest signals from, say, Antarctica, it really isn't a distraction. Signal levels are, at this QTH, generally stronger on the quarter wave than a large delta. Indeed, during a test in extremely stable conditions on 20m with VK3QD (long path, December 2013), there was simply no discernible difference down under in the received signal between the two. Being shorter and thinner, it's infinitely more wind resistant than the delta, uses much cheaper poles as a support, and is very easy to repair if it breaks (although that's largely true for the delta, too!)
If you need any further convincing about the DX potential of verticals, just have a listen to the increasing number of members of the 'Real HF Radio' group, daily down on the beach and challenging or exceeding the boys with big yagis.
It's clear to me that many simple wires, including the 1/4 wave vertical, need an updated assessment, because most of today's texts either don't take account of the powerful digital modes that have come along in the past few years, or just blindly regurgitate tired old texts, sometimes from decades ago, when antennas were largely compared to one another by ear, using either SSB or CW. And inevitably, many of those texts were written by well-seasoned hams, operating large stations and who had long forgotten - or were trying to justify their expenditure by ignoring - what a simpler antenna could in fact achieve.
Books and internet bleating will warn of dire EMC problems if you use verticals to "fire straight into your neighbour's home". There may be an increased possibility of this, relative to a yagi at 15m, but that isn't really a reasonable comparison.
I have seen very slight interference on the PC monitor when running an antenna close to the house, but it is cured in seconds by winding the signal cable of the monitor around a ferrite sleeve. That is something you can do in your own and your neighbour's house without prompting a big fall-out, and at almost zero cost.
The pros for the quarter wave vertical are thus:
- Robust in even hurricane force winds. Mine was the last man standing in the antenna farm during 85mph storms!
- Extremely easy and quick to build - three wires of the same, correct length
- Convenient direct coax feed
- Collapsible for transporting to beach or field use
- Low angle radiation; at a beach, very near to the water, you will easily beat a 3-element yagi!
- Good signal reports
- Cheap! Any old wire can be used.
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