Single Full Wave Vertical vs. Phased Array

•December 5, 2016 • Leave a Comment

vert-vs-array

I don’t want to jump to conclusions yet – but I think it would be interesting to compare a phased array to the N7JW 160M top hatted vertical – only because on 40M – it has really amazed me.

Hard to believe I didn’t superimpose the N7JW vertical over a 40M Phased array in EZnec before – but look at how close a single tall vertical performs vs. the standard 1/4 wl phased array . Very interesting.

DXE-DVA-40-P And the New 40M Phased Vertical Array

•December 4, 2016 • Leave a Comment

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The two verticals on the left are the 40M Phased Array and the vertical on the right is 1/2 of my top hatted 160M RX array – phased and “steered” by the DXE NCC-2. I now have all verticals and the phasing box installed – but some tuning is required, because the DXE Phased Array right now stinks (compared to when I used an Array Solutions Stackmatch II Switch and when I cut my own Christman phasing lines).

careful-scientist

I did use my Rig Experts antenna analyzer and each vertical seemed to be “close enough” to 40M, but while I do see some difference between directions with the phasing box and remote control all wired up – the results are just not right.

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Because it was a lot of work just to get everything up this weekend (2 verticals for 160M RX – which rock now with the NCC-2) and now the 40M phased array, I think I pushed it pretty hard and that doing some measuring and testing out in the back 40 will uncover the mystery of why the 40M phased array isn’t working right.

At least the 160M RX vertical situation is good to go. So that’s a big plus – and some work is always required to tune and get things dialed in just right.

 

Did the DX Engineering 40-VE-2 Verticals Help on 160M?

•December 4, 2016 • Leave a Comment

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I’m using two of these verticals as my 160M RX antennas. They are just under 25′ tall, built like a tank, and have really cool top hats. Here is the hub:

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I can’t tell definitively if the Top Hats do what they theoretically are supposed to – eliminate high angle noise. They do seem to have made a little difference, but since I can’t A-B test – I probably will never know. The ARRL 160M contest is on, and one thing that does seem to be a little different is that the null on the NCC-2 does seem to have improved. I was actually a bit bummed the other day when I got the NCC-2 running with these verticals without hats – it almost seemed like the NCC-2 wasn’t as good at nulling as the NCC-1 was. Now I am sure its as good – and maybe a tad bit better. The null seems a little bit sharper and more defined. It also seems a bit deeper.

One thing I’m starting to see on the NCC-2 is that it does seem to have better “steering” than the NCC-1. When a station is from another direction than another, the Phase control does end up in another setting, which is what I would hope would have happened. I could be kidding myself since its a contest weekend with lots of great signals, but when I had the NCC-1, it seemed like the phase setting was set in one place for the best null and that’s where it set for pretty much any station.

The null on the NCC-2 is definitely “sharper” – you have to tune a little more carefully to find the exact best null. The NCC-1 was not this sharp.

Thee “Accidental Bobtail Curtain”

•December 4, 2016 • Leave a Comment

bobtail

In years past, I tried (unsuccessfully) to get the benefits of  wire Bobtail Curtain. They always sounded so great (in books and online) – but I never found that they were any better than a low dipole – in fact they weren’t even as good as a dipole. W8JI has debunked their legendary status by saying a dipole is a better antenna – and I agree with him. But the model for three elements out of four 40M quarter wave verticals seem to share some characteristics of a Bobtail Curtain. The big difference – I have always been able to get the expected performance out of a 40M phased vertical array. So maybe – this is a variation that will work – I think it will, actually.

3el-40m-vert-yagi

This morning I realize that three elements out of the four are in perfect alignment. The first two were spaced intentionally – because before I had the N6BT DXU-32 – with its 2 element 40M yagi, I had phased verticals using the Christman Method of phasing. This time around, I purchased the DX Engineering phasing box which I believe uses a Lahlum or other W8JI “crossfire?” method of phasing.

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The array approaches a 2 element yagi up a half wave. Even the azimuthal pattern looks about like a 2 element 40M yagi up 1/2 wavelength (sort of)

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Those plots were in the forward direction, with the phasing on one of the two elements that are active in the phasing scheme – and the third element which is parasitic.

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With the phasing in the opposite direction, the gain is only between 1 and 2 dB in that direction, but that’s fine for such a fixed and “accidental” vertical yagi.

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And the elevation pattern. Lets look at the broadsided pattern . . .

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Not bad for a total “Happy Accident”.

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Again – not bad at all given that I ordered the wrong verticals for my 40M DXE phased array, used them instead for my 160M RX verticals with the NCC-2 and then built my own 34.5′ verticals for the phased 40M array – as called for in the manual.

Just for reference, when I had the phased vertical array on the posts and radial system which is now being re-used 2 years after that was taken down – I did use hatted verticals and they worked fine. But that was with the Christman Feed method, and today I will be able to see how this new DXE method with full sized quarter wave verticals works, I can’t A-B this of course, but as a reference, I remember the 2 element 40M phased array was about equivalent to a 40M dipole up close – but not quite as high as a 1/4 w.l, but of course with very good F/B – meaning not a ton of gain but serious directivity.

EZNec is usually a good indicator of real world performance – once you get the model right. Since I went to not connected radials that are modeled .2, .3 or .4 feet above ground, the models seem to be “OK”. I’m going to guess that I will in fact see some of this modeled behavior, but that some I won’t be able to really notice.

Later today – when its u and running, I will report my findings. Another 60 degree sunny day here – December couldn’t be nicer. And one last thing – sitting on that N6BT DXU-32 while waiting a whole year for 3Y0Z and Glorioso “some time” after that was silly – I find that every two years I just have to re-do my antenna farm – its really the most important thing for me in ham radio – I really do get more satisfaction out in the backyard with antennas than I ever have chasing DXCC awards. The horse in the antenna, and the carriage is the DXCC program for me.

 

Happiest Antenna Accident Ever . . .

•December 4, 2016 • Leave a Comment

4el-40

Totally by accident – because I ordered the wrong verticals for my 40M Phased Vertical Array (I ordered shortened and hatted DX Engineering 40M vertical but used them for my NCC-2 based phased vertical array on 160M), I have ended up with a 4 element in line 40M array. Its a lot like a Bobtail curtain or Bruce Array – but end fire. Or in other words, a 4 element 40M vertical beam. Here is what the end fire pattern looks like:

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and

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and now for broadside:

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and

40m-broadside-el

What is happening is the 160M NCC-2 phased verticals are acting as passive reflectors for the two phased 40m verticals that are active and under control of the DX Engineering phasing box.

The top hats of the passive reflectors..

The two reflectors which are the 160m NCC-2 160m RX verts….

A lot is going on this weekend, and I’m having a blast. The weather is gorgeous, 60 degrees and sunny.

The end fire dominant direction is SW, which is great for the LP to ZS and FT5/G.

The broadside dominant direction is SE which means 3Y0Z. So, by accident, my 40M phased vertical array seems to be just what I need to complete DXCC Honor Roll #1, AND while improving 160M RX for DXCC on top band.

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By the way – these DX Engineering resin guy rings are a real dream. Man – they have the best antenna hardware for building your own antennas!

Next I will write about the hats on the 160m verts and see if these short hatted 40m verts as 160m RX pass muster…

160M: Before and After Contests

•December 3, 2016 • Leave a Comment

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I always have hope that several entities that I need on 160M would be on frequencies “holding court” and I just walk up and easily get a new one. That might have happened years ago – but at 84 entities in my chase, contests have been a real bust for me, and this ARRL 160M seems mostly US based. It would be a super ay to go for WAS on Top Band, but that doesn’t interest me.

But before and after contests I find it a lot more fun. Especially just before s contest.

Luckily, we have 60 degree sunny weather this weekend – so I will get the 160M RX and 40M phased array up and running between today and tomorrow.

Then I will hunker down and DX through this coming bottom of Cycle 24. I expect it will come a bit sooner and last longer than we would like. But I think 160M, 80M and 40M will be really fun bands no matter what.

DX Engineering NCC-1 vs. NCC-2

•December 3, 2016 • Leave a Comment

The verticals were in fact tuned yesterday, so here are my thoughts in a nutshell:

1. The NCC-1 and NCC-2 are both great units

2. If you don’t need the additional features of the NCC-2, the NCC-1 is the way to go, especially if you can save a couple of hundred dollars used

3. Noise reduction and nulling are about the same as the NCC-1 – I cannot hear the difference at all. In fact, I almost think the nulling on the NCC-1 was better

4. Have either one of these boxes with say, two phased “20 something” foot verticals with a tuned LC circuit at the base – and it will make the difference between hearing and not hearing weak DX (vs. your TX antenna). I don’t think you will find that the NCC-2 vs. the NCC-1 would make or break you hearing the DX, they are too close from a human ear standpoint, even if the NCC-2 might have better lab specs (although they are actually not fully published yet). I was told the third order intercept in +40dB, which is not much different at all from the NCC-1

Since I do not need or want the RTR feature, and because my old NCC-1 would accept a 160M LPF, I could have just kept my NCC-1.

I’m not lamenting the purchase because I sold my NCC-1 close enough for what I purchased it for (used). I wouldn’t do it again though because the only difference are the new connection features (and RTR, bias T injection, etc)

Anyway, hope this helps you.

If you do not have one of these, and you have an MFJ-1025 or 1026, these DXE boxes are far better, and I encourage Top Banders especially to consider purchasing one.