Hi The Nortel / Trimble units have a DC-DC converter in therm. They pretty much already have all the switcher issues. Of course the up side to that is the regulation that's built in. You can do a diode switch to a backup battery without much effort at all.
Bob On Oct 13, 2013, at 5:21 PM, Jim Sanford <wb4...@wb4gcs.org> wrote: > Someone earlier suggested a group buy of the Jackson Labs device. I would be > interested. > > As for power supplies, my Nortel-TB is on an analog power supply, > deliberately. I do intend to put a scope on it, and see if it may be > contributing noise to the "issues" I see. (I'm wondering if it has > sufficient high frequency bypassing, and sufficient bulk capacitance to deal > with transients.) If it is, I will put it on battery, with the analog supply > as a charger... > > More I think about it, the more I like the Jackson Labs devices. Especially > that they work with the GPSCON software (I think). > Jim > wb4...@amsat.org > > On 10/13/2013 5:47 AM, Robert Atkinson wrote: >> Hi Frank, >> I would NOT put the spare TB on a PC powersupply. Check out both TB's on the >> bench using decent linear supplies. I don't like using PC supplies on >> critical equipment. They are typically designed for a specific (high) load >> on one output (5V on early ones 12V on more modern) to maintain regulation >> on the other outputs. They are designed down to a cost and are often not >> great in terms of suppressing spikes and surges. You are running a sub 15W >> TB on a 100-300W PSU. And then there is the phase noise issue. Whay put a >> $30 PSU on $1000 Frequency standard? A 3 line analog supply is easy to build >> at most 2 transformers two bridge rectifiers a few capacitors and 3 78xx >> series regulators. Surplus (or new) linear supplies are available, I use a >> HTAA-16W-AG by Power-One / Condor / SL Power, like ebay items 300956540240 >> 300956540566 ($15 each). Even new from Mouser they are under $100. These >> high quality 100% duty cycle units are slightly underated for start-up >> current on the +12V rail, but with virtually no load on the -12V and low >> load on the +5V it works fine. I'm in the UK on 50Hz mains so its worse >> case, the PSU has 20% more capacity on 60Hz. >> Bin the switcher! >> >> >> Robert G8RPI. >> >> >> ________________________________ >> From: Frank Hughes <hp_cisco...@yahoo.com> >> To: "time-nuts@febo.com" <time-nuts@febo.com> >> Sent: Saturday, 12 October 2013, 22:49 >> Subject: [time-nuts] Trimble replacement part-2 >> >> Hi, >> Well, now I have determined that the TB >> is actually bad and/or the goofy PC power brick is no longer making >> correct volts. >> >> http://i180.photobucket.com/albums/x257/fish1_07/am/trimble_trouble_zps70b440a7.png >> >> I had one spare Trimble remaining to >> replace it with. >> Not sure what model the new one is, the >> enclosure is red and a different form factor than the smaller anodized >> Aluminum TB that failed. >> >> New one works fine: >> http://i180.photobucket.com/albums/x257/fish1_07/am/Trimble_replaced_10_12_2013_zps5042b487.png >> >> Funny thing, my HP 59309A Clock had >> stopped working, I thought it had a failure too, but when a stable >> 10Mhz signal appeared at the HP input, the ancient HP clock is back >> to abby-normal again! >> I should remember that the HP is also a "miners canary" for the TB... >> >> In a state of delusion, I sent an EM to >> Jackson Labs sales to see if they will sell a Fury >> to an individual..can't imagine what >> Quan-1 $$$ is going to be... >> >> 73 >> Frank >> KJ4OLL >> _______________________________________________ >> 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. _______________________________________________ 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.
