1. One cell works with DCS 1800 (2 TRXs). Everything is ok according to DT and Statistic on this site. No any alarm.
2. But in Spectrum Analyzer we see this cell is interfering to other frequencies (2.5 -2.65 GHz). And guys who use this band (2.5 – 2.65 GHz)are complaing that your frequencies are making problem. After shutting down the site everything is ok, after switching the site it happens again.
My question is: Is it possible DCS 1800 comes to 2500 MHz in any case? If yes, please tell the probable causes…
intermodulation occurs when two frequencies are amplified / combined together. Several additional frequencies are artifically generated (called intermodulation product, or harmonic, of order 2, 3, 4, 5, 6, …).
You can google it, I’m sure you’ll find a wikipedia entry about it.
The formula to find what are the harmonics is :
f(h) = k * f1 + i * f2
with f1 and f2 the downlink frequencies in MHz
k and i : integers that vary between -3 to +3 (they can take larger values, but the higher the factors, the lower the power of the harmonic).