Hi Termination is important. An open cable typically reflects energy down both the inside and outside of the shield. I'd bet the same thing is true to a much lesser extent of an open T connector.
The list of nasties is quite long, so there is no one magic thing that fixes all problems. Bob On Mar 3, 2013, at 10:36 PM, Mark Spencer <mspencer12...@yahoo.ca> wrote: > This is a useful thread IMHO. > > Re the continuous beat note interference issue, I believe I've encountered > this when evaluating a Datum1000B. At first I saw a periodic change in > frequency of several E-10, the typical period was several hundred seconds. > Turning off all the un needed gear in my lab except for a few ocxo's that i > don't want to turn off and using double shielded RG400 cables without > adapters for all the interconnections seemed to make the issue go away. All > the outputs from the un used ocxo's were also terminated with bnc or sma > terminators. Even the BNC T connectors I typically leave connected to the > inputs of my HP5370B's (along with 50 ohm terminators) seemed to cause issues > in this application. > > This issue has also prompted me to give up on my plans to move my GPSDO's > from my radio room to my lab, as it's nice to be able to leave the GPSDO's > running into a terminator vs having to shut them off. > > I've never really put much effort into tracking down the root cause of this > issue but I suspect it is similar to what John mentioned. > > My FTS1050 (which IIRC is based on a datum 1000) doesn't seem to have this > issue, building enclosures for my Datum1000's is on my post retirement to do > list as I suspect running them without an enclosure may be contributing to > this problem. > > As far as I know my BVA Ocxo is immune from this issue as well. > > Regards Mark Spencer > > > > Sent from my iPad > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
