Re: [time-nuts] RFTG-u REF 0 Z3812 as cleanup module for FEI5680A
HI For anything short of microwave multiplication, the 15 MHz output of the Z3810/11/12 is likely to be “good enough”. The 60 KHz noise hump that may be from the power brick isn’t going to make it through a PLL going to VHF, so the only benefit of pulling the brick would be some sort of SDR running directly off of 15 MHz. A crystal bandpass filter at 15 MHz could be made (or found) in that case. The brick probably does a better job rejecting the 50/60 Hz stuff you would get into with a direct supply setup. So let’s see … Nyquist at 7.5 MHz. 1/2 band at 3.75 MHz. You could have a real good radio from maybe 4 MHz on down to DC. That might be interesting, but it’s probably not going to get a lot more people buying these up to do it. Bob On Nov 18, 2014, at 9:22 AM, Bert Kehren via time-nuts time-nuts@febo.com wrote: I would not mess with the power management of the unit, HP did know what they where doing. Any clean up I would move off the unit if you want to stay with the same OCXO you have one in the second unit. As to phase noise before time nuts issues took up all my time low noise signal generators where my main focus and will be again. I know of no high quality Sig. Gen that does not include a 100 MHz XO and in some cases higher frequency SAW units. And that has been going on for as long as I can remember and I am 72. One subject no one has touched on is thermal control. I do not know but suspect forced air cooling that would explain why all connectors on the front. From comments by some members we are looking at 20 W. I will include a fan along with temperature control. Bert Kehren In a message dated 11/18/2014 12:21:32 A.M. Eastern Standard Time, don_he...@gmx.de writes: Hello List, having not looked at the spectra yet as I am confined to mobile phone instead of PC often, I had the idea to marry those two well-known devices to get a nice clean reference oscillator. I remember the spectrum of the FEI as not so nice, and the MTI sounds better. My understanding is yet that I would need to emulate the REF1 unit, basically need to look up the lonely REF tweak with the bridges in J5, maybe fake valid GPS datagrams with a microcontroller and turn the 1PPS pulse from the FEI into that 2 PPSes expected. Replacing the Lucent Power Brick with a linear supply and bridging the tripler to get 5 MHz out might be tweaks to increase the output spectrum further. This was discussed before, I think, i have to look it up too. (I wonder if the REF0 acts up after complete removal of the source REF1 or keep on doing holdover which would be a nice way to take a good frequency standard to a ham radio repeater side) BR Hendrik ___ 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.
Re: [time-nuts] RFTG-u REF 0 Z3812 as cleanup module for FEI5680A
Hi At this point there is no “proof” that the non-GPS REF-0 will run by it’s self. My guess is that it will operate on it’s own with faked GPS messages. Since the REF-0 has a 10 MHz output, there is less need to immediately change around the 15 MHz output. The power brick would be a bit complicated to remove. It’s a triple output unit. Bob On Nov 18, 2014, at 12:08 AM, Hendrik Dietrich don_he...@gmx.de wrote: Hello List, having not looked at the spectra yet as I am confined to mobile phone instead of PC often, I had the idea to marry those two well-known devices to get a nice clean reference oscillator. I remember the spectrum of the FEI as not so nice, and the MTI sounds better. My understanding is yet that I would need to emulate the REF1 unit, basically need to look up the lonely REF tweak with the bridges in J5, maybe fake valid GPS datagrams with a microcontroller and turn the 1PPS pulse from the FEI into that 2 PPSes expected. Replacing the Lucent Power Brick with a linear supply and bridging the tripler to get 5 MHz out might be tweaks to increase the output spectrum further. This was discussed before, I think, i have to look it up too. (I wonder if the REF0 acts up after complete removal of the source REF1 or keep on doing holdover which would be a nice way to take a good frequency standard to a ham radio repeater side) BR Hendrik ___ 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.
Re: [time-nuts] RFTG-u REF 0 Z3812 as cleanup module for FEI5680A
I would not mess with the power management of the unit, HP did know what they where doing. Any clean up I would move off the unit if you want to stay with the same OCXO you have one in the second unit. As to phase noise before time nuts issues took up all my time low noise signal generators where my main focus and will be again. I know of no high quality Sig. Gen that does not include a 100 MHz XO and in some cases higher frequency SAW units. And that has been going on for as long as I can remember and I am 72. One subject no one has touched on is thermal control. I do not know but suspect forced air cooling that would explain why all connectors on the front. From comments by some members we are looking at 20 W. I will include a fan along with temperature control. Bert Kehren In a message dated 11/18/2014 12:21:32 A.M. Eastern Standard Time, don_he...@gmx.de writes: Hello List, having not looked at the spectra yet as I am confined to mobile phone instead of PC often, I had the idea to marry those two well-known devices to get a nice clean reference oscillator. I remember the spectrum of the FEI as not so nice, and the MTI sounds better. My understanding is yet that I would need to emulate the REF1 unit, basically need to look up the lonely REF tweak with the bridges in J5, maybe fake valid GPS datagrams with a microcontroller and turn the 1PPS pulse from the FEI into that 2 PPSes expected. Replacing the Lucent Power Brick with a linear supply and bridging the tripler to get 5 MHz out might be tweaks to increase the output spectrum further. This was discussed before, I think, i have to look it up too. (I wonder if the REF0 acts up after complete removal of the source REF1 or keep on doing holdover which would be a nice way to take a good frequency standard to a ham radio repeater side) BR Hendrik ___ 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.
