DecisionalReview.info

Rip it apart!

This is a “deconstructive” review of Hawking’s corner reflector. Basically I took it apart so you don’t have to! BTW - I am an RF engineer, so I apologize if it gets too technical.

First let me provide a explanation of what a “corner reflector antenna” is. A corner reflector antenna is a very simple, but high gain type of antenna. It consists of a dipole antenna (a dipole is just a straight piece of wire cut in a precise way) and behind the dipole is an angled metal screen or plate which is called the reflector. The angle of the reflector is typically 90 degrees, which forms a corner and thus the name. The reflector focuses the signal so it is more concentrated, which results in higher gain versus a simple dipole.

Taking apart the corner reflector is straightforward, but it does take some time and muscle. I carefully but forcefully pulled on the gray plastic end caps. After some time, the end caps finally came off. This revealed an unlabeled, rather ordinary black “stick” antenna inside the white plastic pipe. It’s probably a 5dBi collinear dipole. The antenna is connected to the coax cable via a panel mount SMA connector. I was able to remove this antenna, but it does take some torque because Hawking applied thread locking glue.

Based on it’s construction, I have no reason to doubt the 15dbi gain claim. However, I seriously doubt the 90 degree vertical and horizontal beamwidths that the manual seems to claim. I guesstimate that 3dB beamwidths are in the order of 40 degrees horizontal and 30 degrees vertical, based on my experience with similar corner reflectors. This makes orientation MUCH more critical. If you are 15-20 degrees off, you could be losing half (3dB) of your signal! On the other hand, such a narrow beamwidth is a good thing if other people’s AP’s/client’s are interfering. Any other transmitters outside of the main beam will be weakened, reducing your noise and improving signal quality.

Now to analyze the coax cable. The outer jacket is unlabeled white plastic, so you can’t tell who made it or what type of cable it is. It’s thin, about 1/8″ thick . I cut off one end to see what’s inside. The shielding is quite good. It’s a dual shield, foil plus braid. The foil provides complete coverage. The braid is tin plated copper and has excellent coverage, probably 95%. The center conductor looks and cuts like pure solid copper, not copper clad steel. The center insulator (the dielectric) is a clear translucent, solid (not foam) plastic. When I soldered on an SMA pin, the dielectric easily melted! It’s probably NOT teflon, but cheaper, higher loss polyethylene. Based on this, it’s probably a RG-174 type cable, not the lower loss RG-316. Cables of this type generally have a loss of 0.6dB per foot at 2.4Ghz. The cable is 6 feet long , so you lose more than half (3.6dB) of your signal in the coax! Making a shorter cable and/or using better cable would help.

Considering how it’s made, a lot of the negative reviews make sense. It’s a 15dBi antenna, but you lose 3.6dBi in the cable so effectively it’s only 11.4dBi. Plus if you don’t point it within 15 to 20 degrees of your target (both horizontally AND vertically), you will lose even more signal. Used indoors, there is so much RF scatter that the actual direction of maximum signal can very often NOT be in the direction of the target due to signals being bounced around. You’ll have to rotate the antenna in different directions vertically and horizontally to find the maximum signal. Used outdoors or in unobstructed area, just point it at the target and you’re done. However, keep in mind that this IS NOT a weatherproof antenna, so don’t leave out outside where the rain and sun will beat down on it.

Used properly, this antenna really shines. It provides a tremendous value for under $50. Antennas with similar gain will cost MUCH more.

Update (5/19/2012): I also found some auctions for this item here.

The featured review for this product, Hawking HiGain Directional Corner Antenna, indoor, 15dBi - HAI15SC Electronics, was written by Daniel Ulanday.

The average rating for this item is 5 out of 5 stars, according to 3 reviews.