Receive Antenna Testing: The “Scientific Method”

W6LVP Loop

I’ve learned not to be in a big hurry when designing and building what is essentially a “potential” new antenna / product. First, there is the EZNec model, then there is the build, then extensive product testing must be done – else you might believe your product is better than others already in the market. In fact, this ends up being quite the journey – and a process of elimination – where you throw out anything that doesn’t make the grade – and in the end – you either have something new and worthy, or you then try something else or go for existing commercial products. I know from experience – where I have fooled myself because I did not test enough. Asking questions is the right approach, in fact, it’s the Scientific Method.

Tests I Need to Make

One test I need to do is test the W6LVP Loop vs. the KY6R Loop. I also need to go get a piece of 1/2 inch flexible refrigerator tube and make a circular loop (I do NOT like the coax loop that ships with his loop). If I’m really adventurous I also could compare against a full size KAZ Loop or TX3A DHDL.

KY6R Optimized 40M Delta Flag

I also could test the KY6R loop with a potentiometer and adjust it for low, medium and high resistance and even test having NO terminating resistor. One thing I did years ago was feed a K6SE Flag at both ends and it seemed to work well – but its been a . while, so I could try this, except in the models, it doesn’t look good at all. Its a complex thing to model – so it could have been my EZNec model was inadequate – especially because the NCC-2 phased each feed and I have no idea what that meant circuit wise at the antenna – in fact, I really can’t model this unless I knew more about what is present at the NCC-2 terminals.

Decisions Based on Test Results

If I find that the W6LVP loop is close to the KY6R Loop, then I would use my two supports, rotators that are 100 feet apart. I’d also use the Wellbrook preamps and have the NCC-2 set up with it’s preamps (that I could switch in or out and compare against the Wellbrook preamps). If the KY6R loop wins – then two KY6R loops are set at 80 feet apart – since that is a physical constraint imposed on me by the space I have available. Smaller loops most definately fit better than these KY6R “behemoth” loops . . .

The W6LVP loop will be sold after these tests because I feel I can make something better. I also have a sneaking suspicion that the Wellbrook preamps will be better than the W6LVP preamp, but I really need to test this and be fair in my comparison. Because of noise and fading on the bands, antenna testing using your backyard – and not some controlled environment is tricky. I have seen some stations and directions on some bands behave completely different than others – and even time of day, day in year and year in the sunspot cycle. In fact, in some ways, there are almost too many variables to come up with some perfect result where you can be 100% sure that something behaves and performs with repeatable and immutable results.

I still believe that these are facts (more than just assumptions):

  1. Using two antennas into the NCC-2 that are the same type and configuration and also spaced at the “right” distance is most important
  2. Feeding Ant 1 on the K3 with the TX antenna – UrbanBeam and then the phased Loops via the NCC-2 is what works the best as far as phasing and nulling out noise
  3. Two phased loops will be noticeably better than one RX antenna 

OK – yeah – this is a “multi – dimensional” science experiment, and I have found that trying one thing, and then building on from that in “layers” is the way to go – start out with the simple tests, then add in the complexity. This way you have less chance of fooling yourself.

 

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