Background:Purchased 900MHz 450i. We are trying it on a tower that we have never had 900MHz on before. We did signal test to a sm yesterday. Everywhere we tested had around a -80 and was able to pull sufficient b/w to satisfy the market. These test were done quickly, drove up to an area pulled out the antenna and ran a router to router b/w test through the 900Mhz gear. It took about 3 minutes at each place we tested.
Question: Ok so after we ran these test, I decided to run a spectrum scan...everything seemed fine at first but the longer I let it run the nastier it got. I am posting two screen shots, one is with the "instantaneous" radio button selected, one is with the averaging radio button selected. You will see in the picture with the instantaneous button selected the spike on channels 912.5 and channel 915. This spike moves across the spectrum and that is what causes the spikes you will notice in the average picture. The spikes normally last for about 1 min and then seize and come back about 3 minutes later. Looking for opinions. Do you think these spikes are high enough to make the client radios disconnect from the AP? Just curious what you guys have found?
Of course, other users can provide actual field experiences, but what you're seeing can be indicative of FHSS (Frequency Hopping Spread Spectrum) devices that move frequencies across the whole spectrum.
At the levels you're seeing it shouldn't affect too much (there are customers using this equipment in MUCH noisier environments), but individual links vary, so no guarantees.
I would love to see others chime in with opinions as well.
Thought I would share one of our spectrum analysis. Now, this is running about 2 feet away from a U* 900 system with 10mhz channel running in 907. Our Cambium sector is running at 924.5 in 7mhz. Even with this amount of noise, we are seeing 10-20mb average per customer. Should get even better once we have switched everyone over.
The noise isolation on these units is amazing, compared to what I have been working with.
