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Pixel RF Pro-1A Review

Review of the Pixel Technologies Pro-1A Moebius Loop
by Seur D'Armadilleaux on the ETON-E1-XM-Radio Yahoo group

This is a rather long-winded two-page review of the Pixel Pro-1A loop. If you just want the short version, then as long as you have 110VAC 60 cycle handy, it's a great buy. It works just as well as an indoor unit (although it will work better outdoors, when its away from the noise and any metal). For those of you who want more, read on.


First impressions, Unpacking, and Assembly

First impressions count a lot, and it's nice to see a company that puts up all the necessary specs (including the Antenna sensitivity pattern) on the web, for easy downloads. Second, the inside sales guys and the job they do are also important, and Brian Graves of Pixel in Colorado did a good job of keeping it short and sweet, and living up to their shipping promises. Hats off. Their website is here.

The Pro-1A came shipped in a box that is 40x40x3 inches, and UPS delivered the sucker without flaw or blemish. Now, that's quite a large box, and best make sure it fits inside YOUR hatchback (it went into mine, with the back seats down, but only just, and only at a bit of an angle). Unpacking the box, again first impressions count, and everything is well-packed and has that look and feel that says "professional grade". This is a case of your getting what you pay for --- nothing looks half-baked, or like someone cut corners to keep the costs down. Even the care taken with foam inserts and sub-component packing is first rate. More appreciation from the customer at this end, guys.

The next step is to go through the paperwork --- yeah, yeah, it's true --- nobody reads the stuff, they just cobble together the likely bits and throw it up on a temporary pole or the nearest convenient tree, right? Well, you COULD do that, what with the stuff in the box which is more or less straight forward and fairly obvious in it's labeling, BUT… there IS a bit of electrical isolation involved, so the order of mounting of the isolation washers, and the orientation of those isolating washers may be important! (So Yeah, read the couple of pages that comes with the product, for once, guys). If you are used to bolting together any of the larger Ham or CB antennas, (or even some of the bigger TV antennas for that matter) then the rest of the assembly is duck soup. Pixel even includes some very clear LARGE pics, for the reading-challenged among us. (And in this case, a picture IS worth a thousand words).

Before you actually test it, you will need a few things. First, a suitable stub pole (the thing that would eventually go into an antenna rotor, if you are going that route, otherwise a piece of ABS plastic with no more than a 2" outer diameter, and preferably about 5 feet long. You need this to keep the pre-amp taut against the "L" bracket, so there is no ground loop. Second, for indoor tests, you need a short piece of cable TV type coax with the F connectors on both ends (don't worry about overloading the receiver because of a short coax run, although Pixel do include some signal attenuators if this does prove to be a problem). Specs and length on that coax test-cable between the loop and the power-inserter-module doesn't matter much for indoor test purposes --- 6 to 10 feet long will do nicely. Last, you MAY want to have a short power-bar with an on-off switch. The Pro-1A is fed with one of those wall-warts, and while it doesn't get particularly warm, it might be better to turn it off when the antenna isn't being used. Last, the Pro-1A kit comes with an RCA-to-PL239 (screw-on CB-type) connector, and if your set has other than that (like an Eton E1 with that PAL antenna input), you may need a suitable input adaptor.

Fiddly Bits

This isn't one of those antennas that you just throw together, while hanging off the top of the tower. While assembly is fairly straight-forward, still there are a number of washers and such that have to be identified and then assembled in the right order. And that means you want to do it where it's warm and dry and well-lit. Take your time with the assembly and make sure the various parts are in the right place, and none of the insulated washers are back-to-front, or you're going to end up with parts touching at the wrong point, and that could result in a short or a ground-loop.

That said, this is an easy antenna to put together, and all the tougher parts come pre-assembled. There are various extra hardware bits, presumably for alternate mounting or alternate feed-lines, and most of the stuff is common North American thread, incase you lose a bolt or whatever. (Don't go losing the insulated washers!) The kit even comes with a weather-proofing package for the connector going into the pre-amp unit that runs down the mast, into the radio shack (a nice touch).

Not Bash Proof

Like many loop antennas, the "loop" part is deceptive in its size. When the box comes, it's light enough, and easy to haul off to your hatchback or van (a bit bulky if you are trying to fit it into a compact car, especially if it doesn't have a hatch). When you unpack the various bits, and lay them out on the ground, the loop itself looks a bit small-ish (unless you compare it to something like a Sony ANLP1 loop). When you get the sucker mounted on a piece of ABS plastic, so you can test it out (and gloat over all the new signals that you can hear), then the assembly seemingly starts to look bigger (OK, so it's just an optical illusion). Part of this is the vertical bulk, part is because you are reminded that the loop is somewhat fragile, going through doors or trying to set it up where there is low headroom.

While the antenna assembly is nice and sturdy, it is intended to go 9 foot above the roof-line and anything around it, and out of the way of anything that might thump it. You are reminded of this, walking the test assembly around the house, cause the loop is big, and its not meant to go jousting with doorframes and furniture. Once it is finally placed outside, you are going to want to prevent it getting hit with falling branches or similar. If you have trees in the area that MIGHT shed branches in a storm, you may want to consider using a bit longer insulated (ABS, fiberglass, or non-ferrous) pole, and attaching it to the plastic vertical support rod that comes with the Pro-1A.

Getting the Test Loop Running

No fuss, no muss, bolt the thing together and tighten the various connectors, and plug it into the receiver. Heavy-duty twine was used to brace the over-sized lollypop loop-plus-ABS assembly between two chairs on the second floor --- nothing fancy. That room doesn't have metal foil insulation, does have big windows, and the loop is about 4 feet off the floor (maybe 20 feet off the ground, outside). Tune the receiver to any medium-strength shortwave station (preferable one you could "just" make out, with some strain, before) and WHAM! The signal is there in Spades, like it was broadcasting from your home town. Really. That said, there's a natural tendency when putting a new antenna on line, to immediately dial in to some of those oddball obscure stations like Mongolia or Solomon Islands (that you rarely, if ever hear), and expect to get brilliant audio right away, regardless of the time of day. That ain't gonna happen.

But this Pro-1A is a really worthwhile investment, in terms of increased signal strength. Impressions are that it gives a solid 6 dB (or more) gain over the Sony ANLP1. And it DOES bring in a number of new stations at respectable (identifiable) levels. It also uncovers a number of ew mouse-squeaks that will all have to be explored with a bit of patience to ID them (but isn't that what SWL-ing is all about?).

If you are used to some other indoor amplified antenna, or a longwire, then you are in for a treat, because a good loop antenna design is really really quiet. Good signal-to-noise, but much more quiet than something like a 60 foot random wire, or even an amplified whip. And the "nulling" capability means that you can turn the loop to reduce the effect of your neighbor's satellite TV dish, that hums like crazy in the rain, all over your reception. (The loop "null" is 90 degrees out of the hole of the donut, and your maximum signal is along the plane of the loop --- seems a bit counter-intuitive for newcomers to amplified loop designs).

As a frame of reference, the little Sony loop is a marvel, folding up to 9 inches or so, and bringing in respectable signals from around 4.000 through 21.000 mHz. It's not so great below 3.5 mHz, but that's asking a lot. And its a bit of a pain, having to use the Sony's pre-selector for the band, but you get used to it. But at $110 or so (shipping extra) it is a good buy. But it is completely outclassed by the Pixel Pro-1A. No pre-selector needed from 100kHz all the way up to 30 mHz, and whopping signals with very low noise. Now, the laws of Physics and radio wave propagation say that Outdoors, High-up, and Really Big will almost always beat Indoors, Relatively Low, and Kinda Compact, and the Pro-1A is no exception.

But if you DON'T own an antenna farm with several Beverage antennas and a monster quad, then this might well be the best $400 you've put out on a compact shortwave antenna. Highly recommended. Especially for small lots, apartments, or ornamentally territorial wives.

Umn, excuse me … gotta go to the local Ham fleamarket and look for a rotor. And the back of the detached garage is calling --- it needs some sort of a Christmas ornament (like a big `O').

editor's note: The PDF file for this antenna can be found here

Date of publication: Oct 25 2010.

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