One nice feature B5c offers is flexibility to work with any dual polarized antenna. A common follow up question is, “What is the best antenna dish to pair with my B5c radios?”
This question isn’t completely straight forward because it really depends on a number of factors that are specific to the link (required gain, operating frequency, dual channel operation, etc).
With that said, here are some of my general rules of thumb when selecting an antenna to pair with B5c:
Gain: Generally, the more gain you can put in a backhaul link the better. However, you need to balance system gain with increased antenna costs and the challenge of deploying larger dishes.
Gain is generally proportional to the dish diameter. The larger the dish diameter the higher the gain. My experience is that antenna gain is often overstated in marketing materials but physical dimensions are not. I like to use the physical dims and assume an aperture efficiency of 50-60% to get a baseline on the expected gain of any dish.
Operating Frequency: Since B5c has a wide frequency operating range I recommend using antennas that perform well over a wide band for most deployments.
Antennas are generally tuned for a specific frequency range. It is more difficult to make an antenna operate over a wider range than a narrow range so many dishes only focus on the upper 5 Ghz band. High quality antenna datasheets will often include a few antenna gains at different frequency ranges to illustrate how performance changes over a wide operating band. Be especially cautious if you are planning to deploy radios in the 4.9 or low 5 Ghz band as 5 Ghz parabola antennas naturally increase in performance as you move up in operating frequency. You should not expect the same performance at 4900 Mhz that you get at 5800 Mhz unless your antenna was designed for that purpose.
Isolation: It is usually worth a little extra money to get a dish that has good isolation.
Antennas can have improved isolation in a variety of ways so it is hard to provide hard/fast rules that apply to the entire market. My personal preference is for deeper dish antennas with integrated RF shielding since I can physically see the isolation but you should know that many other very good options exist.
Aiming/Mounting: Lots of different options here (i.e fine tune adjustments for aiming or special mounting brackets). I won’t go into details but I would recommend thinking about how the dishes are going to be mounted and aimed during the decision making process.
For those who have been deploying B5c links:
- Tell us about your B5c deployment and how you evaluated different antenna options