[600MRG] After Market VFO s comparisons

[Frank Lotito]

On this bulletin board I have seen postings about the QRP Labs U3S TX kit for use as a VFO.  In recent personal correspondence on VFO's the writer's used this kit to salvage older commercial equipment in which the rig's exciter failed and service was long discontinued by the OEM and its agents.  In my own shack a few years back I settled in on the N3ZI DDS VFO kit.  I have used my N3ZI kits (plural) for my 600 / 630 meter transmitter buildups, as well as for classic era boat anchors and home brewed tube and solid state MF and HF transmitter applications.  I have yet to use the N3ZI kits for any type of receiver project.  On occasion I've stumbled across VFO kits from other manufacturers.  I have no experience with those kits.


Does anyone have subjective comments on the U3S vs DDS kits' performance at various frequencies?  Has anyone performed "quantitative  comparative" measurements on these kits?  My specific interest is for LF / MF / HF transmitter application.


Thank you 73 Frank K3DZ / WH2XHA