I would assume they're mostly (not necessarily authorized) copies of existing designs of one sort or another - they're all the same ~$150 price from the usual random 6 letter source names on Amazon or Alibaba. None seem to have any specifications posted (or actual test data).  Ooh, I just saw one for $70 with a "Color display" (although the pictures don't show this) and claims it does have an OCXO (Isotemp 143-141) The Leo Bodnar is about $250 and does have specs (and some independent measurements).  RigExpert has the Tokenblauser  that's a bit more expensive, but has more interfaces, but no test data (and, I believe their factory was recently damaged). Quite a change from the surplus Z3801s of 10-20 years ago  - at least those had a really nice 10811 OCXO in them - all this new crop of cheapies seems to be run of the mill TCXOs as the oscillator, and some appear to be using the SiTime parts (and reprogramming them on the fly? I don't think those SiTime parts have a voltage input, do they?). Which is probably why they don't give phase noise specs <grin>  

Hello, Yes the sitime parts are all digital, they are tuned in (small) steps. The nominal frequency is factory programmed. Here is a datasheet https://www.farnell.com/datasheets/3781740.pdf They claim: Digital frequency pulling via I2C Up to ±10 ppm pull range ±5 ppt pulling resolution Also they're more expensive than an actual OCXO at the same site. Sebastien On 26/02/2025 20:24, Jim Lux via time-nuts wrote: > > > > I would assume they're mostly (not necessarily authorized) copies of existing designs of one sort or another - they're all the same ~$150 price from the usual random 6 letter source names on Amazon or Alibaba. > > None seem to have any specifications posted (or actual test data).  Ooh, I just saw one for $70 with a "Color display" (although the pictures don't show this) and claims it does have an OCXO (Isotemp 143-141) > > The Leo Bodnar is about $250 and does have specs (and some independent measurements).  RigExpert has the Tokenblauser  that's a bit more expensive, but has more interfaces, but no test data (and, I believe their factory was recently damaged). > > Quite a change from the surplus Z3801s of 10-20 years ago  - at least those had a really nice 10811 OCXO in them - all this new crop of cheapies seems to be run of the mill TCXOs as the oscillator, and some appear to be using the SiTime parts (and reprogramming them on the fly? I don't think those SiTime parts have a voltage input, do they?). Which is probably why they don't give phase noise specs <grin> > > > > > > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe send an email to time-nuts-leave@lists.febo.com