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Alpha Delta DX-LB Plus – Part 1 : Arrival


Some preliminary babble…

I had mentioned elsewhere on the site that I’d like to have a 160m antenna. I had given consideration to an inverted-L or a Marconi T, but I came to the conclusion that not only would I not be able to create a vertical section of reasonable height but I also would have difficulty extending the horizontal portion as far as it needs to be and have a proper anchor point for it. And if I could manage to secure the horizontal end, it would be facing a direction that I don’t particularly care about. [It is my understanding that there is some bit of directivity towards the direction that the horizontal portion runs from the vertical portion]

I’d lie if I said I wasn’t interested in 160m DX or working working all states on 160m, but now is not the time to do that. I do, however, want to be able to make my presence known on 160m during the ARRL 160m contest and some of the QSO parties that have 160m as an operational band.

Since I have experience with the 42′ Alpha Delta DX-EE dipole, and since I think it is well constructed and has performed quite well for me, I figured I’d throw down the nearly $200 for the DX-LB Plus dipole. This is shortened 160m/80m (shortened) that will also handle 40/15m, with additional parallel wires for 20m and 10m operation. My DX-EE tunes 30/17/12 and I’m hoping I’ll be able to get a match on these same bands with the DX-LB Plus without too much loss.

The dipole arrived and is still packed up. When I removed it from the box I was surprised at how heavy it was. It’s well constructed. The wire is heavy and of course the addition of the inductors makes it even heavier. I suspect that if I don’t manage to get the dipole erected in a way that the two ends are 180 degrees from one another, it’ll probably cause the top section of my Max Gain Systems mast to bow.

I really can’t stand wiring up the parallel wires. And I really don’t want to think about tuning and pruning it so that it’s resonant inside of the CW sweet spots of 160m and 80m, especially since the 3:1 bandwidth is very narrow.

I’m still debating whether I should put this up as a flattop oriented E/W (broadside N/S) or as an inverted V. Either way the center will be @40 feet. If it is an almost flattop, the ends will be at about 30′. If it is an inverted V, it’ll really be rough to have the ends very far off the ground — probably no more than 10 feet, although I’ll strive for 13-14 feet.

As constructed and delivered, it is intended to be fed with coax. However, I do have the option of feeding it with 450-ohm ladderline (~45 feet) into a DX Engineering 1:1 current balun, through an 8′ piece of RG-213 into the radio. If I have too much trouble tuning the antenna, I may opt for feeding it with ladderline as it will make it easier to tune. Of course, feeding it with a random length of ladderline into a balun is not quite the same as feeding it with only ladderline and tuning it with a tuner that accepts balance feedline.

Already I’m losing ambition, just like I did with the DX-EE. It took me three weeks before I ended up putting the DX-EE together since I had to string the additional parallel wires through their standoffs and secure htem at appropriate points. In this case it’s going to be even more difficult since I’ll be dealing with trying to get it to be resonant in a specific small portion of 160m and 80m.

I’ll write more as things progress

Written by Mike

October 14th, 2010 at 3:52 pm

Posted in Antennas

Tagged with , , , ,