So the last year or 2 we have had Sparks 4g wireless at work here, and it always seemed to have speeds of between 30 to 40 odd Mbps. Lately it seems quite slow, and on a good day I get up to 25 to 30, but often its like 10 to 20Mbps.

Have reset the Huawei B315 modem etc, and tried different locations in the office (the building is a tin shed, so I have it sat by a glass door to outside)

Its just feeding one laptop for day to day office work, so didnt really want the hassle of trenching across the drive for fibre.

Should I look at adding antennas to the modem? I have some ones I could take off an old adsl modem, or are they different again? Or do I try some sort of bigger/outdoor antenna?