The input spec for a Spectrum Analyzer that lists maxium dc voltage, how imprtant is this? Most scopes I have seen are in the range of 25-50vdc. There is one that lists it aa "0 vdc". I don't understand how it can be "0" anything other than that tells me there can't be any dc voltage present. How important is this spec and where/when would it come into play? Next, I need a "Return Loss Bridge" for taking 'Distance to Fault' and VSWR readings. The device from the scopes manufacture is ridiculously priced $1500). Anyone have suggestions of something much cheaper?