Why does the signal quality jump?

Question

Computer networks

Good afternoon

I am in the area, the distance from the tower is supposedly about 7-8 km.
From the phone, I steadily catch a 4G signal right from the window, and the speed is about 20 Mb / s.

For home Internet, I brought a directional antenna to a height of ~ 4.5 meters (such a blue, passive one), and threw a Keenetic router with a port for a USB modem onto the roof. Modem Huawei E3372. As a result, a coaxial 5-5.5 meters goes from the roof, after which it is connected to the modem through an adapter, and this whole structure is connected to the router.

As a result, the modem is connected via 4G, and the signal is usually 15 / -75 (CINR / RSSI), the speed is under 10-15 Mb / s.

It seems to work, but CINR keeps jumping between 0 and 15.
RSSI usually fluctuates between -75 and -53.

I look through Kinetics, and there CINR is updated every 2-3 seconds in the UI, and it happens like this:
15 -> 12 -> 8 -> 5 -> 2 -> 9 -> 6 -> 1

As a result, the Internet is unstable, speeds are always different.
Interestingly, this is not always the case, and sometimes the Internet just flies all day.

Tell me which way to look?))

Answer 1

If the coax is some kind of rg-6, then the length must be reduced and check how it is connected to the antenna. And the pigtail on the modem is homemade or factory? 5 meters for 4g is at least 3 dB of loss, half the antenna gain is often. Place the modem as close to the antenna as possible, use a USB extension cable, but you will have to find a very good one, on most junk only a mouse can work. What is the blue antenna? What is written on it? is it for 4g?

Answer 2

Buy mikrotik with sim card, type SXT. Put it on the roof
From it, throw the twisted pair cable down
Don't you think that the router on the roof is a little awesome from the weather?)