Support QRP CoA Everywhere

Tuesday, 12 April 2016


OK lots going on (over most of the summer).

I have an ultra light weight G3TXQ DX 6 band Hex beam being built for me, will be just 6KG. Near the sea verticals will win always but if inland this might be better, when DX will use a DX wire 10m HD pole. Will almost certainly use at home QTH, using a Racal 9m (or 11m) pump up mast.

After a lot of reading ON4UN book about low band DXing and lots of conversations I will build a portable 4 square setup for 17m and 15m (as well as could be used on 20m/30m and 40m with a change in control box and transformer lines). Another version is here

Next time when I find the Oceania and JA openings from islands in EU or vice versa I might stand a chance to work the DX op against the wall of callers who are 180 in the opposite direction. The major disadvantage with omni vertical antennas.

The key will be the phasing box and the diagram of the one I will use with a Collins Hybrid Coupler is shown. T1 and T2 will be using T106-2, T130-2 or T157-2 cores, I will see if they get warm. The dummy load I will use will be  50W chip resistor attached to a 1U CPU heatsink but at QRP power levels I do not expect, if the antennas are built correctly, to have a high reverse current. If two antennas they will be Attached to Ant 1 and Ant 4 and the transformer lines are 1/4 wavelength and light weight low loss 50 ohm coax. If using all 4 then I will use ex-virgin media (new) cable TV cable which is double foil wrapped and has 75ohm impedance. I will use F type connectors for the transformer line to control box connections. Each vertical will be using a fishing pole (5m for the higher bands) and I will craft a connection 'plate' that will sit on the pole support or raised above ground level. To this the radials, transform line and element will be attached. I intend using non-latching relays. So if the power goes the antenna defaults to one location.

For 23cm looks like I have managed to scrounge an RC-5 rotator (might do double duty at home QTH with the HexBeam) and controller, will need new cable between as they hacked the old one off apparently when removed. I expect I will ground mount this so will use a thrust bearing higher up.

The 23cm antenna just to play initially might either be a 23el Tonna (G7SOZ will probably have that) or a 28el quad loop. No photo yet but they will come. the 28el quad loop should look like this one from G6GVI

I will retire the central support in the garden, the pump up mast will go at the bottom and should be far enough away from the trees on the East side of the garden (chain saw will fix stray branches) and move the end support (where the Racal now will go) to where the centre one used to be so can still put up 80m dipoles etc. I suspect I will add a 12.5m pole support in same location of the pump up mast and use that with an inverted L configuration for 160m and 472KHz.

The 6BTV will go and I suspect the unused YP3 3el portable yagi will be sold off as well. That trims down the antennas (and adds a few!)

The workshop will see the cobweb (6,10,12,15,17,20) go back up so I will have a HF antenna for testing and the TV antenna that is there right now (unconnected) I may remove from the mast.

The WX stations will see new batteries and one might have a web cam fitted.

No comments: