How to calculate your Antenna box dimension shipping weight?

The antenna shipping cost is one of the major concerns for WISPs, The UPS ground is a common way for shipping those antenna packages. The UPS dimension weight calculation formula is the following:

Dimension weight = length x width x height /139

For example: 
A MimoTik Mesh Grid Dish Antenna, 
4.8-6.5Ghz 26-28dBi 2 feet Dish 4- pack 
Shipping Box dimension 28 x 28 x 10 inch,
Gross weight 24 lbs,
Dimension weight
= 28 x 28 x 10 /139 = 56 lbs

The UPS shipping charge will based on this Dimension weight .