Wellbrook v. Pixel, Round 1

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mbott

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I had a Wellbrook ALA1530LNP-2 delivered a while back so I thought I'd do a comparison of it versus the Pixel/InLogis RF Pro-1B and my short answer is … no significant advantage to either one over the other. There are differences, but they appear to me to be minor.

For my HF listening, which is primarily from 3mHz to 18mHz, I could find no situation where either one was better or worse than the other. The differences that I noted are in their operation. I have a known noise source in the neighborhood and both antenna systems were equally able to reject that noise. However, they did that at differing compass settings. The Pixel at 170° and the Wellbrook at 150° according to my antenna rotator. Not exactly a reason to claim victory of one over the other. If conditions ever improve in the upper HF frequencies, my plan ts to compare them both again but for now that is pointless.

Personally, I prefer the construction of the Pixel over the Wellbrook for 2 reasons. The coax connector for the Pixel, which hangs from the bottom of the antenna mounted preamplifier, does not appear to be as stressed as the connector for the Wellbrook, which sticks out of the side of its amplifier module. Secondly, I prefer the support the Pixel adds to the loop with the vertical support that is not standard with the Wellbrook. Note that the Wellbrook Antenna interface requires 12v DC while the Pixel requires 24v AC. Powering the Wellbrook will be much easier from a single car battery on any DX-expedition.

The Wellbrook is the one currently up and running, so I’ll continue with it for a while. If it looks like we’ll get several days of no rain, I may swap them in and out for some more comparisons.

Hopefully I be able to run some more testing shortly.

--
Mike
 

ka3jjz

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There are numerous questions that this test brings up. On what frequencies did you run your tests? At what times of the day / nite? Which of your receivers did you use? Did you use more than one receiver in your tests? What did you use to measure your results? Did you test MW and LW, along with HF? Which stations did you use as a benchmark? How did you mount the loops? Are they the same distance from the home? Were they fed with identical lengths of coax? If you had both loops active at the same time, how far apart were they? How high off the ground were they?

Without some hard statistics, no one can really expect to draw a scientific conclusion from your tests, interesting tho they might be. When running a test like this, details often matter.

Mike
 

prcguy

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For antennas like this that have internal preamps, you can get an idea of high signal level handling capability from the power they consume. Cheaper low level preamps that easily overload might use 12V at 25ma or less, where better performing preamps might use 12V at 100ma or more. For 24V units, 50ma or more would indicate they are using higher power transistors that would do better with high RF levels.

Do you have the current consumption values on the Pixel and Wellbrook units?
prcguy
 

mbott

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Evidently it is unfortunate that I used to word "test" in the next to the last word of my write-up. I should have just stuck with using the word comparison. I'll keep that in mind for any other write-up I may decide to share here.
 

ridgescan

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I had a Wellbrook ALA1530LNP-2 delivered a while back so I thought I'd do a comparison of it versus the Pixel/InLogis RF Pro-1B and my short answer is … no significant advantage to either one over the other. There are differences, but they appear to me to be minor.

For my HF listening, which is primarily from 3mHz to 18mHz, I could find no situation where either one was better or worse than the other. The differences that I noted are in their operation. I have a known noise source in the neighborhood and both antenna systems were equally able to reject that noise. However, they did that at differing compass settings. The Pixel at 170° and the Wellbrook at 150° according to my antenna rotator. Not exactly a reason to claim victory of one over the other. If conditions ever improve in the upper HF frequencies, my plan ts to compare them both again but for now that is pointless.

Personally, I prefer the construction of the Pixel over the Wellbrook for 2 reasons. The coax connector for the Pixel, which hangs from the bottom of the antenna mounted preamplifier, does not appear to be as stressed as the connector for the Wellbrook, which sticks out of the side of its amplifier module. Secondly, I prefer the support the Pixel adds to the loop with the vertical support that is not standard with the Wellbrook. Note that the Wellbrook Antenna interface requires 12v DC while the Pixel requires 24v AC. Powering the Wellbrook will be much easier from a single car battery on any DX-expedition.

The Wellbrook is the one currently up and running, so I’ll continue with it for a while. If it looks like we’ll get several days of no rain, I may swap them in and out for some more comparisons.

Hopefully I be able to run some more testing shortly.

--
Mike
I notice on my Wellbrook, that the direction especially in MW "feels" about 20* off too. Silly, but I wonder if it's the position of the feedpoint related to the loop-notice it's about 20* offside from the loop. With an amplified antenna could this be a factor?
Far as the Pixel's support beam, what exactly does it guard against? I have an ongoing problem with the Wellbrook where the signal still is affected by high winds. It cuts in/out in MW but not SW with gusts but only about 30%-not completely. Still annoying though. Thank God I deployed the wire antenna-great for high wind DXing. I ruled out the feedpoint and feedline. So it must be the loop mount at the amp up there. I think with wind, the loop element can twist within that mount changing the signal. I have the screws torqued down super tight short of cracking the amp casing. I am thinking of fabbing a brace for this situation that would brace that loop element better taking the load off the mountpoint.
 

mbott

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Far as the Pixel's support beam, what exactly does it guard against? I have an ongoing problem with the Wellbrook where the signal still is affected by high winds.
I've noticed the Wellbrook will lean based on the direction of the wind. I've not seen any evidence that this impacts its reception ability on SW, But there is movement and I'm not sure what this will physically do to the loop over time. I've yet to see the Pixel do anything like that.

--
Mike
 

ILSAPP

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Do you find that the welbrook loop worth the price for who that lives in a flat with a balcony? Long wire seems to get much noise in my sangean 909x.
My main interest is SSB HF aero comms.


Thank you
 

Newage

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Ok guys I'm need of advice.
I'm running a AoR 8600 mk 2 radio, and use it for HF only, I'v tried the whole long wire thing but just
Don't have the space or an under standing wife.
I've just picked up a second hand Wellbrook active loop antenna.

Iv moved its location around my garden 3 times now but my HF reception is still not great.
I'm in the UK so I can pick up military HFGCS traffic from time to time.

I'm thinking about relocating the antenna to the roof line of the house, the loop would then be about 22 feet above ground level, I can also shorten my coax by quite a lot, I'm using Westflex mil spec coax.

What are people's thoughts.

Thanks Mike T
 

ka3jjz

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Well what do you mean by 'not great'? The 8600 isn't all that great of a receiver to start with. You really can't expect that a good antenna is going to make a poor receiver work that much better. Some improvement, yes, but it isn't ideal by any means. Unfortunately when you buy a wideband receiver, performance compromises are taken to cut costs. Oh and before I forget - if that radio has an attenuator, try turning it off. Here on the East Coast of the US, that radio has a reputation for overloading issues, so I could easily see why someone would need to put an attenuator on it. It's quite possible that you might need to adjust the Wellbrook's gain to prevent similar issues.

While these loops can be mounted in the air, I've also seen them mounted on a tripod on the ground, hidden in a garden, etc. Getting it away from the house is always a good idea, but height isn't really necessary with these loops.

Also keep in mind some basic laws of propagation - listen above 10 Mhz during the day, below that at night. As we are slowly approaching summer, the higher frequencies should start to propagate somewhat better (if only the sun would cooperate...). And by their very nature, HF Aero can be there for a moment then gone. To get a better idea of how your radio and the Wellbrook is working, I'd try tuning some MW. That's a far better way to test than trying to get something that's very hit and miss.

Mike
 
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