Tuesday 31 December 2019

Just...couldn't...resist...

When I bit the bullet in October and grabbed an as-new IC-746 for 2m work, the idea was to slowly get everything going over the winter, ready for maybe early April 2020.

But then - the Great Tropo Event!

So extensive, stable and long-lived has the last week's tropo been that some have taken to calling it the 'tropo of the decade'.

Forecast looks promising for more tropo. 
I couldn't comment, but the distances achieved with simple equipment might well lend some credence to that assertion.  After all, my own QSO with EA8 yesterday was achieved at both ends with 3-ele antennas (Yagi here, quad there), and 30-40W.

Such conditions are not yet over, although they are much weaker this morning.  By January 02, things look like they might get even stronger than last week, at least for a day or so.

So, having resisted the urge to buy a larger 2m Yagi for days, yesterday I took the plunge and ordered a 8-element.  In fact, I once had a 5-element quad which was extremely capable.  But it was a timber-and-wire homebrew, and those never last very long in the wet weather of Wales.

I had initially opted for an LFA from Innovantennas, the maker of my 12m Yagi.  Some of their Yagis now come with rubber grommet, friction-only securing for the elements, obviously with a view to portable assembly/disassembly.  This is no good for my windy location, as the rubber will soon perish and the elements start flying!

I did get a reply from Innovantennas about getting a clamped-element 'legacy' version supplied.  But when I asked about the price, an answer there came none.

Well, I can't hang around for e-mails, so I opted for the Antennas-Amplifiers Yagi, which seem to be well made and good value.  I was going to buy one direct from Serbia, but the shipping costs are quite high.

The 8-ele PA-144
Eventually, I discovered that several UK outlets sell these antennas, such that the final price (£128) is equal to or somewhat cheaper than the direct method - and without the potentially serious delays and hassle if something arrives broken in the post.

The 8-element is a good compromise between gain, price, physical size and windage.  Beyond 8 elements, the boom length starts to creep up to 4m quite quickly.  At 2.92m, the 8-ele is perfect for my purposes.  The overall ERP with maybe 120W out of my amplifer and the effect of considerable ground gain is likely to be around 13kW.

Although connectors at lossy VHF are to be avoided where possible, the on-board balun and N-connector is useful for when the antenna has to move, or rat-nibbled coax has to be replaced.  In the end, my EA8 QSO was made not with £9 per metre LR600, but with about 10m of spare RG-8X - hardly ideal, but it worked (and still only represented a ~1.5dB feeder loss at that length).  Never allow the perfect be the enemy of the good!





1 comment:

PE4BAS, Bas said...

Hello John, good luck with your new antenna when it arrives. I think building an antenna yourself for this band would be more satisfying but I doubt you can do it for the price of a pre fabricated model. 73, Bas