Hi Some of the probes are pretty good. Others are a disaster fidelity wise. Always good to check one before buying a bunch of them. The tough part is that some of the bad ones look just like the good ones.
Bob On Mar 18, 2011, at 2:38 AM, Bruce Griffiths <bruce.griffi...@xtra.co.nz> wrote: > The cheap probes probably lack the resistive inner conductor in their > interconnecting coaxial cables. > This results in a poorly damped transient response. > > Bruce > > Eric Garner wrote: >> I too, fell for the siren song of cheap Chinese probes. 2 years after >> I bought 4 of them, only one has not failed. However, my 1980's >> vintage probes from Tek still work dandily. >> >> >> >> On Thu, Mar 17, 2011 at 12:47 PM, beale<be...@bealecorner.com> wrote: >> >>> Yes, I am controlling the OCXO frequency with a voltage input (center tap >>> of 10k trimpot from +5V to ground). I hooked up my custom 26 MHz PIC >>> divider* and was able to trim the OCXO to match the output of my GPS 1pps >>> signal to better than 1E-9 (at least for short periods of time). >>> >>> These parts draw about 60 mA at +5V in operation in a 23 C ambient >>> environment, after a brief one-time warmup pulse of about 200 mA. The can >>> gets a bit warm if left open. I taped a small thermistor against the case, >>> and made a little styrofoam box to nest snugly over it and measured the can >>> case temp to reach about 50 C when thus insulated. >>> >>> I am accumulating some performance data on the two units I have and can >>> post it online if anyone is interested. (actually, I was thinking of >>> buying a bunch more before posting the data, because the price seems too >>> good to be true). >>> >>> * http://www.bealecorner.org/best/measure/time/source/ >>> >>> Scott Newell wrote: >>> >>>> That's a great price for any OCXO. Do they have EFC? (I can't tell from >>>> the part number in the auction photo.) >>>> >>> At 01:41 PM 3/17/2011, beale wrote: >>> output of a 26 MHz Pletronics OCXO in a 14DIP can (by the way these go >>> for $2 online, the cheapest OCXO I've seen). >>> >>> >>> _______________________________________________ >>> 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. _______________________________________________ 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.
