I’ve also learned the new Airmux-400 hardware that supports 100 Mbps asymmetric speeds will soon support 100 Mbps full duplex symmetric. It will require double the channel bandwidth (40 MHz), but the benefits will outweigh the loss of some non-overlapping channels. And with so many different bands to choose from, I don’t think it will be an issue anyway.

If you haven’t deployed wireless networking where possible with RAD Airmux-400s yet, you should look at the possibility. A system can be deployed in a few hours and it can save you a bundle over the long run. I’m talking thousands to hundreds of thousands of hard dollars.

All the information on the Airmux-400 as well as all of RAD’s products can be seen on out sister site www.RADProductsOnline.com.

On our site, which is easy to navigate, you will find RAD’s entire catalog of products along with the ability to order online at discounted prices, the first in the world to offer RAD online exclusively. For convenience, we have also included data sheets, product manuals, product performance calculators, white papers, catalogs, and other useful information to make choosing and buying RAD products easy.

If you haven’t taken a look, please visit www.RADProductsOnline.com soon. A simple registration is all we require in order to have full access to everything on the site.

What amazes me still are the shear number of IT and network personnel who haven’t heard of wireless bridge connectivity or who have a misconception about what wireless bridges are. Many assume anything wireless falls into the 802.11 category and they don’t want anything to do with it. Others think of bureaucracy laden licensed wireless that seems to take forever to implement and costs a small fortune. If you fit into one of the above categories and are obviously reading this post, let me say, wireless bridges are none of the above. Advances in wireless technology have brought us high-speed Ethernet connectivity that’s very reasonably priced, secure, easy to deploy, and readily available.

Why are you still insisting upon using those old sluggish T1s or costly T3s that keep on making Ma Bell rich. You need to look into how you can reach your remote facilities within a 50 mile range wirelessly. The bridges we recommend are the Airmux series from RAD Data Communications. The Airmux-200 ($3000 to 4500 per complete system) and Airmux-400 ($6000 to $7500 per complete system) are both carrier-class radios that have been proven over the last 5 years to be extremely reliable even in adverse weather conditions.

I welcome any comments any of you may have regarding wireless connectivity. I know there many wireless standards and schemes out there, but what we focus our attention on this site is brute force reliable connectivity. If any of you doubt what we’re talking about here, I invite you to tell us what you think and hear it from those who are already enjoying the benefits of high-speed wireless.

In the new era of connecting the LANs of remote facilities together, the Telcos don’t want you to know about point-to-point broadband microwave bridges. Why? Becuase the Telco’s bread and

Flat-panel antennas viewed from atop a water tower

butter business is selling bandwidth in the form of T1, T3, and Sonet leased lines. Over the years, business has tried various methods of  “bypassing” the Telcos by installing their own dry copper or dark fiber where possible. Until 8 years ago, connecting remote offices or facilities amounted to dialup ISDN at 128 kbps or on the high-end, T1 circuits running at 1.544 Mbps. Neither was a great choice for bandwidth-hungry Ethernet applications, but they were faster than anything else at the time. Anyone who ever had to pay for one knows they can get very pricy. And the cost goes on and on indefinately month after month.

Always looking for a better and faster way, manufacturers began offering wireless devices for the 802.11 WiFi market that could be “stretched” in some cases to go a little farther. But not until the 5 GHz frequencies were opened up did any of that really matter.

Today, wireless bridges that operate in the 2.4 and 5 GHz bands routinely span distances of up to 75 miles at speeds of 50 Mbps and higher and require no  licensing by the FCC. The benefit for business is obvious–the return on investment for a single link averages about 6 months, and that’s not even factoring in the increased bandwidth over the cost of the T1 circuit the wireless link is replacing. After that, there are no recurring costs associated with point-to-point wireless connectivity. Recognizing the need for security, today just about all wireless devices encrypt data at AES128 or better making them ideal for sensitive data. Wireless bridges do have a distance limitation compared to terestrial TDM data circuits, but where they can be deployed they absolutely save business a bundle.

Although unlicensed wireless microwave technology has been around for close to ten years, business has been somewhat slow to adopt it primarily due to misconceptions or myths about microwave systems. Many skeptics associate point-to-point broadband wireless bridges with consumer-grade 802.11 WiFi which it is not. Wireless bridges are a completely different technology designed to do exactly what I have described in this article. For more information regarding the benefits of wireless bridging click on the Benefits tab on this site.

Advanced Encryption Standards (AES) have become the de facto standard for wireless backhaul microwave radios these days. Many people I’ve talked to have voiced concerns about sending their sensitive data over the air for all to capture. Many confuse point-to-point wireless backhaul microwave radios with consumer grade 802.11 WiFi which bears little resemblance. But, as much as I reassure them the over-the-air signal is encrypted, they seem dubious about the prospect of deviating from their normal means of remote connectivity–usually leased lines or even fiber. The FUD factor of using wireless has been used by the telcos to dissuade their customers from the technology since it cuts into their bread and butter business. What the telcos don’t tell their customers is the very data circuits they sell as “secure” are in fact not very secure at all. To make matters even more confusing, many government and independent bank auditors have been equally misled.

One bank client I recently met with expressed strong doubts about the use of wireless compared to T1 leased lines .. the logic being–since T1s are point-to-point, non-public data circuits, they’re secure. Well, that’s not necessarily true. I asked the bank customer if they use T1s for transporting voice and data and they answered yes. I asked if they were encrypting one or both over the T1s and they answered, “no, why would we..T1s dont’ run over a public network so they’re secure”. The real truth is, T1 circuits can be easily tapped at various points including manholes, utility poles, shared-tenant phone closets, and yes…even at the telco central office itself if someone wanted to capture sensitive information. When I was on premises at some of the competitive local exchange carriers (CLECs) I worked with over the years, during voice-quality listening procedures we would routinely monitor  live voice conversations by connecting a test set to any given T1 or E1 circuit by plugging into a monitor jack on their DSX patch panel. Easy. Fortunately, I was the “good” guy and and did not have a reason for capturing any sensitive information for illicit purposes. I was listening to how conversations sounded over the voice compression equipment we installed, not what was being said.

The  business world is operating under a gross misconception that telco leased lines are “secure”. The sad truth is they’re not. Wireless technology had to be encrypted for obvious reasons. So, why are so many reluctant to deploy wireless where it makes sense? The short answer is, education or perhaps the lack thereof. That’s why I launched Wireless-Maven.com..to truly have a single point of reference to point potential clients to help alleviate their fears and uncertainties about wireless.

Attempts to crack AES encryption by using brute-force means is best described by the scientific community as futile. According to all accounts, to successfully crack AES would take a single computer running cracking software billions of years to crack AES 128. Even using the fastest super-computers today working in tandem would take literally hundreds of thousands of years to crack. OK, so maybe it can be cracked..but a million years from now, who’s going to care anyway. The U.S. government has approved AES encryption for the transmission of highly classified secret information.

The bottom line about wireless encryption is it’s there…unlike traditional leased lines it truly is secure. And when you couple the speed virtues with the lower cost of deploying wireless, it just makes good sense to consider it for your business.

Dual-polarity parabolic antenna

In broadband wireless, there are many types of antennas available to suit the requirements of the application. The primary aspect of antenna selection is usually gain. But equally important criteria include such things as beamwidth, side and rear lobe rejection, cross-polarity isolation, and VSWR (voltage standing wave ratio dud). Antennas also come in single and dual-polarity models. The newer dual-polarity antennas are used in MIMO (multiple-input–multiple output) technology where there are actually two transceivers in each radio–one connected to the vertical polarity of the antenna, the other to the horizontal polarity. Click here for a short primer on antennas courtesy of KBT Communications, Inc. By transmitting and receiving using two radios on the same frequency–just on opposite polarities, MIMO wireless devices can actually achieve twice the throughput compared to a single radio of the same channel bandwidth.

Dual polarity antennas as it turns out are not all created equal. We tested a number of dual-polarity parabolic antennas that showed very good specifications. But some of the test candidates flunked our tests miserably. The throughput performance and error-rate are highly dependent on the amount of cross-polarity isolation of the antenna or antennas in the case of two physical antennas with their feeds polorized opposite one another. The minimum isolation should be at least 22 db, perferably 28 db or even better. High quality antennas are generally going to cost more, but the performance payoff is worth the difference.

Antennas are available in several different physical shapes, types, and sizes. Flat panel antennas have become very popular in broadband wireless due to their relatively small “faceprint”. Flat panel antennas are rectangular or square and generally have gains in the 21dbi(approx. 12″x12″) to 28 dbi (24″x24″) range. They can be an attractive choice since they don’t require radomes for harsh environments unlike parabolic antennas and “blend” more easily with surrounding architecture. Beamwidths of flat panel antennas in the 21 to 28 dbi range are generally from 9 degrees to 4.5 degrees respectively. Beamwidths (patterns) and passive gain are mutual. Simply put, high-gain antennas achieve their gain by concentrating RF energy in a narrow pattern or beam. The narrower the pattern, the higher the gain.

Grid antennas usually consist of a curved or parabolic reflector made of light-weight tubing or wire mesh. Grid antennas are tuned to reflect and focus RF energy to the feed assembly whereas parabolic antennas are usually solid metal. While grid antennas present a much lower wind-loading factor, they generally offer less gain in a given size compared to solid parabolic reflectors.

Some new generation broadband wireless bridges are incorporating a small flat-panel antenna ( 12″x12″) with the active transceiver components making for a very compact unit. The feed from the unit is usually fast Ethernet with power coming via a POE injector located inside. The gain of the “integrated” antenna units is in the 18 to 21 dbi range with beamwidths of 9 degrees.

If you don’t know which antenna is best suited for your project, contact a specialist or drop us a comment. We’ll be happy to respond to any questions or comments you may have regarding this or any other post on this site. We’ve tested a number of different types for our own clients and will be happy to share the results.

Welcome to Wireless-Maven.com where in coming posts you will find a vast resource of useful information about how you can realize substantial increases in your company’s remote office bandwidth while saving a bundle in the process. Check back soon for some really great news, tips and tricks, reviews, and application articles specifally aimed at the use of unlicensed microwave backhaul multiplexers.