Having decided to completely revamp the shack, one of the first questions to arise was what antennas am I going to put up? I’ve been using a 3 element tribander for 10, 15 and 20 metres mounted on my specially reinforced chimney, and variants of wire verticals on the lower bands. You can see details of the antennas I’ve had on the station page. Most antennas I’ve used up to now have performed reasonably well from a radio perspective but durability has been a problem.
Decisions for the low bands i.e. 160, 80, 40 and 30 metres weren’t hard to make. I’m going to build an updated version of my successful and proven inverted L for 80 and 160 metres so it includes 40 and 30 metres as well. The 80 and 160 metre version has performed very well and adding 40 metres is an easy option to keep me on that band; 40 metres isn’t a huge priority band for me over the next while as I’ve my highest DXCC country total on that band and will be concentrating elsewhere for the foreseeable future. I’ve never really been active on 30 metres up to now, so any half decent antenna will do at this stage. If past vertical performance at this site is anything to go by, it’ll be a decent performer on 30m. For receive on the lower HF frequencies I’ve a very trustworthy K9AY that I am certainly going to keep, though it needs reconditioning. I also have a partially constructed N/S bi-directional beverage for 80 metres that I will finish and I’ll be installing another at more or less 90 degrees to the first. I’m very fortunate to have both the space to install such an array and accommodating neighbours who will permit me to do so.
These criteria were ordered based on the specific needs I have. Others will of course have different needs and different constraints and priorities but this is how design goals fell out for me on this occasion. I want a station that will stay on air in the worst Winter storms we get, that won’t require a huge amount of time or money to maintain, that has a relatively low visual profile, that performs reasonably and doesn’t cost me a fortune. Many hams will be surprised that performance is only 3rd on the list.
It came down to a simple choice for me – do I want more time on the air with a less efficient antenna or better performance with more enforced periods off air. I’ve never spent enough time on the air and want to change that, so the durability and longevity goals won out over on-air performance.
The challenge was what to do for the higher bands i.e. 20 through 6 metres? I wanted a change from the tribander partly because I live in a very exposed spot that is open to storms from the North Atlantic in the Winter; the highest wind speed recorded since I’ve lived here (2000) is 75 knots (139kph/86mph). Although thankfully I’ve never had a serious failure on the tribander, just a few element tips coming off now and again, I tend not to sleep that well when the storms go through. The tribander is also getting to end of life and I just thought it’d be nice to hear the radio World through different ears for the next while. Though I’ve led something of a charmed existence with the tribander, looking back over the last decade I’ve realised that durable antennas have been a real challenge – I’ve had lots of other antennas fail over the years – and consequently I’ve spent alot of time and effort keeping wire and aluminium in the air due equipment failures. My tribander rotator also died earlier this year and that, along with the remains of many past antennas I came across when cleaning out my shed over the Summer got me thinking about design criteria for my new antenna farm. After some mulling over, I came up with the following:
- Durability (maximise survivability)
- Longevity (minimise maintenance)
- Performance (reasonable efficiency and directionality)
- Visibility (low visual profile)
- Cost (keep it some way reasonable)
Criteria established and site surveyed, it was time to ask the tough question; what antenna(s) for each band from 20 metres to 10 metres? I dug out my old reliable favourite antenna book, the ARRL Antenna Book and did some revision. I also spent along time online looking at various options. I thought about my site and my priorities. I read extensively. I slept on it for many weeks. I did alot of doodling. I walked the land over and over again. I got a crick in my neck looking upwards to my various antenna supports – my tall house and various trees around my site. I considered and reconsidered various configurations. A possible solution emerged after a number of weeks and many possibilities had been considered and rejected. From that point on, while other possible configurations bubbled up, I kept coming back to that particular configuration. In the end, I couldn’t escape a conclusion that was staring me in the face.
The antenna arrangement that would best fit my situation was a suite of dipoles for 6 through 20 metres, consisting of a pair of dipoles one half wavelength high for each band, erected at right angles to one another and each antenna fed independently to maximise flexibility; I could feed either antenna on a particular band independently or together, in effect giving me two or four beam directions. The setup, if done right would be very durable, require little maintenance, perform well, wouldn’t be terribly visible if done right and wouldn’t cost that much either. An added bonus is I’d have 100% redundancy on each band so if I did have an antenna failure I wouldn’t end up off air as a result on the affected band.
The focus since making that decision has been on engineering the most durable, lowest maintenance, least visible solution I can come up with. I’ve put quite a bit of work into identifying antenna parts such as pullies, mounting points for the house and trees, suitable guy line, antenna wire, dipole centres, toroids for the 1:1 current baluns at the feed points and coax cable. You can read about the dipoles antenna I’m building at the projects page. There’s something very satisfying about ending up with such a ubiquitous antenna as being the appropriate solution. At this stage of my radio journey, it feels right to be going back to basics so to speak. The resulting station if hooked up to a 100w transmitter will constitute something of a standard candle station on-air as well, a nice bonus. It’s good to have reference points out there, part of the reason I monitor the NCDXF beacons so closely.