60dBm.com 0.1-3000MHz Return Loss Bridge

This article is an expose of the internals of a 60dbm.com 0.1-3000MHz Return Loss Bridge available on eBay for around $17 incl post.

Above, the 60dbm.com Return Loss Bridge.

Above is the published directivity characteristic for the RLB.

Above is the Return Loss of two very good 50Ω loads measured using a Rigol DSA815-TG. The Rigol has a firmware defect (Chinese quality) and halves the values plotted, so Return Loss is double that shown on the display.