40M Phased Array verticals at KY6R. There are 44 buried radials that connect between each vertical plus chicken wire ground screen not connected to anything. The chicken wire helped hold the radial wires on the ground – and then the grass grew over the wires. This ground system seems to work exceptionally well. The creek bed is just below these verticals to the right.
One of the reasons why I deep-sixed my old blog is that I had some posts that were getting really out of date – and I mean a LOT of them. Back in the day, I was very much into Cabella’s Crappie Pole Moxon’s and a Christman fed 2 element 40M vertical array. With more experience (and new products coming on the market), I have found some better antennas and approaches. I’ll get to the Moxon antenna in a subsequent post – but lets take a look at the Christman phased array “replacement”- the DX Engineering DVA phased vertical array system.
One of the things that I have come to love is the DX Engineering DVA-40-P 40M phased array system. DX Engineering will sell you the entire kit – and its kind of expensive, but luckily, I had the aluminum for the two verticals in the array. I purchased the DVA-40-P controller gear – which consists of a switch and a remote control box – and all I can say is – these guys really know how to build some serious gear – and the outside switch has the absolute best gasketed weather proof case I have ever seen. Its also UV protected – which believe me – is super important. I was feeling lazy, so I paid them to build the phasing cables – you can save good money if you do it yourself.
In the old blog I sang praises of using an Array Solutions Stackmatch II switch and cutting the 3 antenna cables (2 feeds and one delay) using the VA7ST Christman calculator available online. The approach is well documented in the ON4UN Lowband DX-ing book, but I now think the DX Engineering approach is far superior. Its the same thing electrically – but mechanically, I feel like the DX Engineering approach is better.
I can say without hesitation, just go to the DX Engineering web site and purchase their gear. Yes, it will cost about $200 more total, but believe me – it is well worth it. One reason is the durability and weather proof part – the other is you only need two cables from their phasing switch, and no set of crazy coax T and L connectors. Its a much more “elegant” solution – and that means a lot when you want something to work over several winters, and heck – even the heat of summer.
The delay line is essentially replaced by a toroidal transformer. These units would be very easy to repair in the field if need be.
What is especially nice is having two simple feed cables and no delay line. Its VERY easy to cut the cables incorrectly, and if you do – your phased array will be a very disappointing exercise in futility. With the DXE boxes and cables – the only thing I had to do as build the two verticals (I pop rivet and use Alumox on all of the top sections and then use a bolt at the first section so I can slide the element up and down and tune each element per DXE’s very well written instructions), and using my Rig Experts AA-30 antenna analyzer. In fact, it took maybe 1/2 hour per vertical to tune it to the frequency that the DVA manual suggested so the center frequency would be at 7.150 mhz.
I even purchased a second unit – so if one blows up, I can actually fix it myself. I will have no downtime this way, and believe me – when Bouvet hits the airwaves in just months – you better have 40M in your quiver of antennas! Conditions on the high bands have been so close to bottom of cycle conditions – I am thinking that the 3Y0Z propagation predictions are actually a bit optimistic. I hope I am wrong, but 20M is EXACTLY like it was at the bottom of the last cycle – there are maybe 3 or 4 stations on the air – and they are just US stations – no DX. They are all weak. Yes – there is an occasional spike – but this downward trend is real and somewhat “alarming”.
During the last bottom of the cycle – if I did not have a 2 element phased array on 40M, I would have almost just shut down the station for 2 or 3 years.
For two years I had the N6BT DXU-32 and had to take it down so I could get serious about 160M, while retaining something decent on 20 and 40M.
The DXE DVA-40-P is not quite as good as the 2 element “shorty” 40M yagi I had up at 50′, but its not too far behind. The difference between the two is when you will get in the log – with the phased array, you will be in line right after all of the full sized and shorty 40 yagi owners – and you will be before the high dipoles and the 41′ verticals and low dipole and inverted vee DX-ers.
Here’s something to consider – 2 phased verticals close to ground is childs play to maintain – even a high dipole (with squirrels eating through my support rope) was trickier. And the DXU-32 on a tower – that was a massive undertaking compared to the phased verticals. Also – if you have an HOA or CC&R – you might get away with two aluminum or wire verticals in your back yard.
Again – if you want to work serious DX and rare ATNO’s in the next 4 years or so – you better have at least a 2 element phased array – and the DXE DVA-40-P is the easiest way to get serious fire power on a small lot!