Turning a 6m squid pole into a 4m squid pole
The other day, I placed an order at Haverfords for a couple of heavy duty squid poles, one 6m and the other 7m. The 7m pole was as a back up for my existing pole (and to amortize the shipping costs over more than one pole). The 6m pole was chosen as I had an idea, and I didn’t want to waste any more money than necessary if it turned out I was mistaken.
One of the more common approaches to antenna deployments in Australia is the squid pole/linked dipole or squid pole/EFHW combination. It combines the ability to get the antenna at a reasonable height, without the compromise of a loaded vertical antenna. The only drawback with the squid poles we tend to use (sourced from Haverfords – get a 7m heavy duty one) is the fact they are too big to really travel well, being about 1.2m long when collapsed.
I have travelled to VK4 with a squid pole, which had to go into oversized luggage. Despite the best taping, the rubber bung in the end was lost, and in general it’s a pain in the backside to carry the thing around the airport taking it to oversized luggage, etc. What would be great would be about 50-65 cm in length travel squidpole that still gave you at least 4-5m of height.
Now, my idea, concocted in the middle of the night when I couldn’t sleep, was that I could take an existing squid pole, cut each section in half, remove a little bit for the telescopic sections, and voila, I’d have a slightly less than 6m pole, that fitted into my checked luggage. The basis for this theory was the idea that each pole tapers at the same amount, so it should be easy enough to move the position of the friction locks half way up.
Turns out I was wrong.
As might be visible in the above image, all of the sections of the pole can be removed by unscrewing the bottom cap, and tipping them out the bottom. What also might be visible (apart from the mess on my shed floor) is that actually, not all segments taper as much as the rest. In fact, the bottom sections don’t taper much at all.
This makes logical sense – certainly far more logic than the idea of a perfectly conical taper my sleep deprived brain had concocted. The bigger lower sections provide more strength, and so are much thicker, and it is really only the top two sections that have any significant taper. I didn’t notice this until after I’d made the first cut, of course.
The first section – the top one, was hacked in half – two sections of 550mm – with a hacksaw, and fed into each other. Success! It left a section of about 1m in length when telescoped. A loss of 10cm for a halving in the size of the pole seems a good tradeoff.
The next section wasn’t so good. It did work, in that the top section did push through about 40cm of the one above that, for about 1400mm of pole, but the lower section hardly had any give at all. In fact, the taper really wasn’t there. The two sections, 550mm each, telescoped to about 650mm. Hardly a good gain, and the point at which I realised I’d miscalculated.
I continued, as I’d already hacked the pole in half, working my way down the sections. In some cases, I simply threw one of the sections away, and, using duct tape, thickened the bottom section until the friction lock would work. By the time I’d finished, I’d thrown out three sections of the pole, and the total length was about 3.2m. In short, I’d lost half the height, and probably most of the performance.
I left it for the night, and came back the next day. I noticed the sections I’d thrown away fitted together nicely, for a 1.5m pole or thereabouts, when it dawned on me I could get some more height that way. These sections, 550mm in length, are kept separate to the main pole, but slide over the top, adding another metre or so to the length of the pole, but more importantly, they add a significant amount of rigidity to the whole affair, effectively double-walling some of the lower sections.
In the end, the pole was about 50mm shy of 4m, but the aim, to get a pole that fitted into checked lugged (or carry-on, for that matter) was achieved. Total length, bung inserted, is a fraction over 600mm, split into two sections. I am, of course, aware of the 4.7m pole that can be sourced from Europe, but I cannot see how it would be cheaper than the 30 odd dollars spent on this one.
I have yet to test the pole in anger – it may simply collapse in a shocking display of contempt for my ideas, but I will be sure to update the post once I’ve had a chance to.