They were announced at WARC-79 in 1979 (the clue is the name there )
They started getting added to various amateurs’ allocations around the world in the following years as there was a period to allow some commercial services to migrate.
One thing you tend to notice is because there is no contesting on them there are fewer people with monster antennas.The multi band beams often have fewer active elements on 17/12m than the 20-15-10 parts of the same beam. I can’t remember but there was one 5 band Yagi that was directed 180 on 17/12. i.e. point beam 90degs for 20/15/10 and switch to 17/12 and you find the beam now pointing 270degs.
Radial has 61cm of extra wire that is wound on support, tie wrap marks 20m length. There is enough to lengthen the radial. Tie wraps are attached at 17m and 15m positions. Excess radial is wound onto support.
Start of radiating section. There is a short off-cut of RG58 with BNC plug. There is about 1.5 cm of shield folded back and taped down under the yellow tape. The centre connects to the radiator where the plastic bulldog clip is.
I used it in CT3 but really couldn’t get it to work properly with varying ground conditions. Reverted to my original linked dipole for later activations.
One day I just might get out and activate again
ISTR Barry telling me the height of the radial at both the feed point and the far end fundamentally affects how long the radial should be. In the one I built the feed point is about 83cms AGL. You have to tension the radial so it doesn’t sag noticeably in the middle. It’s why the radiator is made from Teflon covered silver plated wire but the radial is very lightweight PVC 7x13 hookup wire. I remember trying a radial made from the Teflon wire (it wont kink when you wind it) but it was so heavy I would have needed several supports to keep it above ground. So I went for lightweight wire.
Remember: I made this as a vertical antenna with a possibility of working DX that fitted on a 5M pole. Fitting the pole was the primary design requirement. It worked well in periods of good propagation (2011-2016). It certainly enabled me to work plenty of stateside stations on 5W SSB/CW and correctly sited on a beach in EA8, I was able to work E51KIK at 16500km using just 5W SSB.
A link 1/4 wave GP would be a much better antenna but you wont fit one on a 5m pole. ISTR a 1/4GP for 20m needs an 8.5m pole and 17m needs a 7.15m.
After I temporarily gave up on your design Andy, I made a 20m “up and out” so at least I could try a vertical. The counterpoise is about 60cm up and it’s guy rope is tied to a guyed walking pole at the other end. It tunes OK on any surface and is really handy and quick to get on the air. I still use my 7m pole, but just leave a couple of sections telescoped at the bottom.
It’s taken two guys (me & Josh) with over 70 years commercial programming/admin experience between us 3hrs to figure out what was broken on the database. I’m not saying you will not sort out your setup but based on your MT sys-admin’s performance tonight you may not find it too easy
In other, but related news, I failed to get my 20m “up and out” vertical to work on the very rocky summit of GM/ES-026 Sgor Mor this evening. I’ve only ever used it on grass or snow, so could be the ground causing the issue.
The outer probably needs shortening a bit to a lot depending on the ground, the state of the moon and the price of fish! Or it’s easy with something like an MFJ259 than using the SWR meter in the radio.
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