PMP450i integrated sector AP -- antenna separation with onmi 940MHz antenna

Products PMP
1

May someone provide an official Cambium guidline for verticle antenna separation betweenPMP450i integrated sector AP and other omni antennas ?

AI has lots different answers.

Thanks,

Linda

2

Linda,

There is no official antenna separation spec because there are so many different situations. The primary variables are:

  1. Are the transmitters GPS synchronized, with timing and frame length parameters the same? If they are GPS sync’d, then likely 1m antenna to antenna vertical edge is far enough apart. If they are not GPS sync’d, or the timing is not the same (for example, 1 uses 5 ms frame, the other uses 2.5 ms frame length, or 1 uses 75/25 TDD split, and the other uses 50/50 split) then the distance they must be separated is much more - 10m may not be sufficient.
  2. The frequencies and channel bandwidth used in each AP.: if there is no GPS sync, then the closer the frequencies are together, the more separation required.
  3. The antenna polar charts. Every different type of antenna will have some value of isolation in a vertical direction (either up or down).

If all the co-located 450i radios are GPS sync’d properly, the minimum required distance from antenna bottom of the top antenna to the antenna top of the bottom antenna is about 1m. Since the 450i can run in GPS sync mode, or in auto-sync mode (just sync’d to itself), and can be tuned across the entire 5 GHz band, there is no way to publish an easy spec for minimum isolation.

If you are interested, I can add a fool-proof manual method to determine what non-GPS sync’d radios might need for isolation.

3

Just FYI, Cambium only makes 450i AP’s with integrated sector antenna for 3GHz and 5GHz. They do not make one for 900MHz. So I’m not sure what you mean by “separation with omni 940MHz”… which is in a completely different band. Can you elaborate a bit more on what you’re trying to accomplish or issue you’re having?

4

Hi Dave,

Thanks for your help.

We currently have four sector antennas (PMP450i integrated APs) mounted horizontally with synchronization, and they are operating well. Another party is proposing to add an Omni antenna operating at 940 MHz, which is part of a different system and not associated with the Cambium network.

I am interested in your manual method.

May you please send it to me?

Thanks,

Linda

5

Hi Eric,

Thanks for your help!

Omni antenna operating at 940 MHz is part of a different system and not associated with the Cambium products.

We’re seeking guidance from Cambium regarding recommended separation distances on a radio tower between Cambium PMP 450i integrated sector AP (5GHz) and non-Cambium antennas, based on wavelength or other RF considerations.

Thanks,

Linda