Tag Archives: Point-to-Point Bridging

Appreciating Siklu- An Un-a-bridged Tale

You gotta love a good bridge… like this gorgeous unit in Moravia, NY:


If that bridge could talk it would tell you stories from my childhood. It would also speak of my own children flying across it on their bicycles countless times through the years. Lovers holding hands as they stroll, school picnics, photographers marking the change of seasons… Ah, memories.

*Ahem* That’s NOT the kind of bridge we’re here to discuss though (but thanks for indulging me on that). Friends, I’d like you to meet the Siklu EH-600TX. I’m impressed so far, and so feel compelled to share some thoughts with anyone interested.

I have two of them newly in production, forming a point-to-point bridge link, and a third sitting in a spares cabinet waiting to jump into service if ever the need arises. The birds-eye view of my link goes a little something like this:


This unit is absolutely “carrier grade” from a build quality perspective. The EH-600TX works in the unlicensed 60 GHz spectrum, and I added the license that gets you to 1000 Mbps aggregate capacity, from the base 500 Mbps. You can slew your up/down to be asymmetrical if you so desire.

The 60 GHz spectrum is a mysterious place where oxygen absorption  of all things needs to be understood (see this quick primer), and the transmitted beams are often described as no bigger than pencils or dimes. Wireless bridges of any sort can be hard to align, and the tighter the beams the more true that statement becomes. Yet Siklu provides excellent directions and an alignment methodology that let a technician who has not done a lot of this sort of work get it right fairly quickly.


Given the weirdness of the 60 GHz spectrum, I really wanted to exercise this link in crappy weather before turning it loose on the network. The skies over Central New York have obliged, as we’ve had a fairly miserable spring and early summer with plenty of Florida-grade Sheets-of-Rain and Walls-of-Water sorts of storms. Through them all, the Siklu link did not blink.

After pressing the new bridges into service for real, I realized I should probably get the latest firmware put on them. As with the alignment process, Siklu provides good directions for this task. And the total time of upgrade-related outage is petty impressive:


In testing via iPerf and other trusted verification metrics, I find that the EH-600TX delivers what it promises for speed and capacity. So far, it’s been a great experience.

This link is replacing a licenced 80 GHz Exalt setup of similar capacity, and it’s so nice to work with “palm-sized” hardware (as Siklu describes it). We also have smaller Exalts and LigoWave bridges in service, but this Siklu is now our big dog from a capacity perspective.

We are running the link as simple as possible, with it functioning as a patch-cable in the air in a simple extension of the LAN. But there is a lot that might be done with the bridge’s three Ethernet ports, and I encourage you to dig more into Siklu’s capabilities if interested.

Time will tell if I made the right choice with the Siklu EH-600TX, but the early verdict is that it’s a winner.


Please note- if you are new to point-to-point bridging, make sure you get educated on rooftop safety, licensed versus unlicensed frequencies, proper mounting procedures, and grounding techniques. None of this is particularly daunting, yet there are plenty of ways of getting it wrong- leading to failed links, damaged downstream equipment, and potential injury or death.


Faster Wireless Isn’t Always Better Wireless

There- I said it! Let the trouncing commence, as I fully realize the title of this blog borders on sacrilege for those of us that do wireless for a living. But, after you curse me and Google my image to throw tomatoes at, give me a chance to explain what I mean.

Different Frequencies, Speeds For Different Applications

We of the Wi-Fi mindset have the numbers 2.4 and 5 etched upon our psyche. We know that these numbers are followed by GHz in our version of reality, and that depending on what we do with spatial streams, output power values, and antenna designs, we’ll achieve fairly standard (to us) rate-over-range permutations that more or less make up the various possibilities for connectivity that we provide to our clients. Not exactly news, right? Let’s take a quick look at some other frequencies, applications, and data rates that you might not be aware of, before I get to the point of this blog: 

  • Frequency: 76 Hz. Application: ELF Military Comms. Data Rate: a fraction of a bit per second
  • Frequency: 60 kHz. Application: Atomic Clock. Data Rate: 1 bit per second
  • Frequency: 4235kHz. Application: WeatherFax. Data Rate: 45 bits per second
  • Frequency: 144 MHz. Application: “Short-range” Amateur Radio. Data Rate: 1200 bits per second
  • Frequency: 900 MHz. Application: WLAN P-P Bridging. Data Rate: 50 Mbps+

You know the rest of the story- as we go up in frequency to the familiar 2.4 and 5 GHz ranges, we can achieve higher data rates with generally shorter distances in play. We also know that power output and antenna configs contribute to cell range capabilities, and that modulation types ultimately decide what we can do with a given channel width at a specific frequency. This is wireless 101, yes?

And us wireless types get jazzed over HIGHER speeds, not lower- this I know. But I’m here to tell you that it’s worth stepping outside of our normal for a bit and spending some time on the last bullet in the list above- 900 MHz- and what it can do for us.

What’s So Exciting About 900 MHz?

To most of us doing normal, day to day Wi-Fi, the answer is “nothing”. The lowly 900 MHz space is meaningless to the modern WLAN. But… some of us also have to do point-to-point bridging on occasion. Even here, 900 MHz is generally considered a dated technology as we put in our fast licensed and unlicensed bridges that deliver hundreds of Mbps or even Gig speeds on really neat hardware that needs line of sight to work.

Wha? What was that last part?

“… on really neat hardware that needs line of sight to work.”

So what happens if you can’t get line of site? If you didn’t know better, you might just say “I cannot do this link, for I don’t have line of sight! Everyone knows ya gotta have line of site! I can’t do this!” But not all bridge links NEED blistering throughput and “carrier-grade” expensive hardware. There is some handy gear out there available for 900 MHz bridge links that can overcome many LOS challenges you’re likely to hit, and still provide a few dozen Mbps of throughput. Depending on your creativity and skills, you can also use of couple links in parallel to double your fun. 900 MHz will go through trees, small buildings, and can feel like magic compared to the more strict LOS-dependent characteristics of the higher frequencies.

Ubiquiti gear is among the more popular in this space, and this is the sort of use case that gets people excited. They don’t need gobs of throughput, but do need to get through obstacles.

Read a few of these testimonials (there is almost a cult following of sorts to some Ubiquiti hardware) and you can get the sense why 900 MHz is popular in agricultural settings, where there is distance to cover, trees and terrain changes are a fact of life, and where moderate throughput is better than no throughput when you want to link things up. I recently learned of a farm-specific hardware line from Ayrstone that includes infrastructure and in-vehicle components in what amounts to a really fascinating product set (yes, it based on Ubiquiti, but with proprietary firmware.) Ubiquiti isn’t the only player in 900 MHz kit, but they seem to be the most visible.

Your 900 MHz Mileage May Vary (and so might your noise floor)

Out in the boonies, 900 MHz has a fighting chance as a bridge solution given the lack of people who might have competing devices. Get near a population center, and things get more worrisome for 900 MHz hardware. There are lots of cordless telephones that use 900 MHz, and in the Amateur Radio world, 900 MHz is also known as the licensed 33cm band. Here you’ll find a mix of activities from voice to data and FM to sideband, and hams usually get to use a lot more power than unlicensed network equipment. There may be pagers and other unlicensed 900 MHz gadgets afoot as well.

If you need non-LOS bridging and don’t have contention for the spectrum from nearby devices, 900 MHz might be the slower-speed solution that works when the stuff that you’d rather use wont.