Frequency Hoppers...problem or not?

We are in the design/field analysis stage of our canopy implementation and have noticed frequency hoppers all over the place! (902 - 928) We are using an Anritsu spectrum analyzer and have found different intensities in different locations (obviously expected). The question I have is about a proposed tower location of ours. We are planning to locate a 150’ tower (where our AP cluster will be mounted) on the same grounds that a communication tower already exists. The spectrum analysis of this site has led us to believe that one of the hoppers is probably coming from this other tower (-47 dB reading both horizontally and vertically polarized!!!) Is there any way that locating our tower on these grounds can work since the nature of hoppers is intermittent and narrow?? …or should we start looking for different locations? Also, on a more general basis…how are frequency hoppers affecting your solutions? Thanks in advance!!



I believe that those hoppers that you are referring to are frequency changers that prevent people from monitoring secure communication like the cell phone systems use in the 800mhz range.

If you are planning on deploying the Canopy system in the 900mhz range and find multiple “hoppers”, maybe you should look at a different specrum like 5.2 or 5.7ghz unless you have alot of foilage in your area.

How many other locations do you have to choose from? Will the location in question bring a large number of CPE’s to your business?

I still need to do a frequency analysis of my proposed tower locations.

Thanks for the reply MRVNet. We are definitely stuck to the 900 MHz, lots of foliage everywhere (Southern Indiana, US). We haven’t really looked for other locations, and this location is owned by the city already. The network is actually for the water and sewer utility, but will then hopefully expand over time. Therefore our subscribers at this point are fixed city assets. This location is basically the most centralized spot in the city (probably why there is already a tower there) and will pick up about 40 (about 1/4 of the total) of these assets. We pick up the changer/hopper throughout the city, but it is at its highest intensity at this tower location. We will be about 50’ higher with our tower than the current tower, so that will help. Just not sure…

The only way to know for sure is to get an AP and set it up. Take an SM and do some testing within the coverage pattern of that AP. Then turn it 90deg and repeat until you know what you can really expect.

If you can find the owners of the other 900 equipment, they may be able to exclude frequencies from their list opening up a clear area for your Canopy.