I recently bought a Rigol DSA 815 TG, and am very happy with it. As a non-engineer hobbyist, this is the ultimate price/performance gizmo for me! The first thing I did was build a Return Loss Bridge from the ARRL site from an article circa 1997. I built it using leaded parts in a point to point configuration similar to Zach Lau's unit pictured in the article. I used an on-hand, unknown material ferrite core for the detector transformer. The darn thing seems to work pretty well for a $5.00 tool... Here is a plot of it from 0 - 500 MHz with a non-precision 50 ohm resistive load. I did not set a marker at 2.5 MHz, but that seems to be the lowest practical frequency. The sweet spot is around 62 MHz. I seems quite usable to 250 MHz, but pretty marginal by 500 MHz. For my ham radio purposes, it seems good to go for HF - UHF, even if the ulitmate accuracy is suspect at the higher frequencies.
So... Am I fooling myself with this thing? Is it really worse than I am making it out to be? How does it compare to a Mini-Circuits or other $100 class RLB?
Thanks,
Len