For my part, erecting quads, yagis, loops, etc. can be a challenging task indeed. The sheer weight and size of the thing means that quite often a one-man-effort to fulfil all stages of the erection process (i.e. assembly, tuning, mounting, handling, etc.) is an onerous one. The key here in my opinion is ‘how’ and ‘where’ the antenna is elevated when each of these procedures are being carried out.
Why Elevate?
A chief thought when erecting any antenna should be ensuring that it’s free of obstacles from the ground to the sky.
Powerlines are the most obvious ones to avoid when assembling verticals, but with horizontals like yagis and quads the obstacles are situated much closer to the ground. These might include trees, bushes, fences, pets, clotheslines, kids, kids’ toys and more which might play havoc with elements or spreaders which extend at large distances from the boom.
On this point, making certain the antenna is free of obstacles usually necessitates it being elevated from the ground in some way. Not only does this enable the antenna to escape potential hazards such as those listed above, but it also allows the owner to move with freedom both beneath and above it to more easily adjust elements, spreaders, fittings, the gamma match, etc.
An elevated antenna – depending on how and where it’s done – will also enable you to get a more accurate SWR reading from your antenna during the tuning stage.
As the collection of photographs below show, horizontal antennas can be elevated using a variety of different methods. Here are some popular ones…
Elevation Options
1. Saw-horses
Photographs 1 (See above), 4 (4 element yagi for 20m) and 5 show large yagi antennas raised on saw-horses more commonly found on building sites.
These are beams with four legs more typically used to support a board or plank for sawing but they do the job well indeed for antenna assembly.
A pair of saw-horses (also known as a mule) can also be used as the base for a portable table by placing a sheet of 3/4″ plywood or even a door on top of two saw-horses.
Furthermore, if the saw-horses are strong enough, the table can be even used as a platform for radio equipment, although with caution if the top isn’t secured to the top of them.
2. Chairs
Photograph 6 shows a monster 8 element yagi resting on 3 plastic chairs some 45 cm off the ground. While high enough to facilitate construction, tuning the antenna at this height would have provided some very inaccurate readings as it is just too close to the ground.
There are also pine trees nearby which no doubt provided a potential hazard when attempting to manoeuvre the antenna onto the tower. I wonder if the turning radius was also affected due to the close proximity of these trees…
3. Ute or truck
Photo 7 shows a team of field day buffs resting a UHF/VHF antenna on the tray of a utility vehicle. It also shows one of the team members fixing cable ties to the boom to restrict the movement of the feedline, another benefit of having your antenna elevated during assembly.
One benefit of using a vehicle for elevation is that the antenna can be very easily moved if need be to a different location to continue the erection process.
3. Rubbish bin
Wheelie bins, a type of rubbish receptacle, are also effective stands for antenna assembly. Sturdy constructions made of recycled plastic products, these stand approximately 2 meters tall and provide good height above ground for assembly.
Tuning
Elevating the antenna by a few feet by one of the above mentioned methods is necessary for assembly but for the tuning stage other steps are required.
When tuning your yagi, I recommend standing it ‘on end’, with the reflector elements down towards the ground, and the director elements aimed towards the sky.
You can do this by propping the boom against a 2nd story porch, or if you have a regular wood construction house, then just propping it against the house, with the boom resting on the edge of the roof or a rain gutter or something, works. This will more closely simulate a real installation above ground.
I’ve never found a great deal of difference when testing a yagi in this manner then when it’s on top of the tower.
Unlike a two dimensional yagi which extends across the horizontal plane, a quad is three dimensional and has elements which extend as far below its mounting point as it does above.
Quads, therefore, require additional working space to assemble spreaders and wire, for handling, etc. Finding ways to elevate them, therefore, are much more difficult.
Many antenna makers such as Mosley, HyGain and Cushcraft suggest the best way to elevate and then tune an antenna is not to stand it on end but to place it on an 8-10′ wooden step ladder to get a rough check. This is a terrific way to tune a quad also in my opinion.
By all reports, they will balance fine on the ladder/s if not too windy but will still incur an SWR change when mounted on the tower.
Some hams also like to tune larger antennas when raised by a crane a few times to check SWR /for tuning before mounting on tower.
The photo on the right shows a 4 element yagi being elevated by a scissor lift. This is a motorized vehicle that has a railed platform which can be raised straight up in order gain access and perform work on areas that are difficult to reach. The convenience of using a scissor lift to manoeuvre a large antenna onto a tower or for tuning purposes has been appreciated by many.
The security and ease of working from the basket of a lift compared to working off the rung of a ladder and the safety risks that are involved make the scissor lift the easy choice when working from heights.
While such means are expensive, I believe that if you’re going to spend a large amount of money on a monster antenna then surely you can afford to spend a bit more on the installation.
Hopefully this article has provided you with a few ideas for your next horizontal antenna installation. If you know of a better way or can suggest a further way of elevating your antenna for assembly, etc. then please make some comments below 😉
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