Re: [time-nuts] Good GPSDO on eBay?
My experience is different. When I received a broken item from China, it was damaged in shipment because it was poorly packed, the seller told be to keep the broken part because he did not want to pay to ship something he would just toss in the trash. eBay's current policy is given here: http://pages.ebay.com/help/policies/money-back-guarantee.html It says that for items not as described the seller pays for return shipping. It seems that what you did was go through paypal who might had a different policy they need to handle transactions outside of eBay On Sun, Jul 10, 2016 at 2:23 AM, Clint Jay wrote: > No, my experience with Chinese sellers, even when you file a "not as > described" case, is that eBay will require you to return the item at your > own expense if the seller has stated they will not pay return shipping. > > Ebay's attitude was that the seller could just state in their item > description that buyer is to cover return costs and that's it. Game over. > > Which is why you occasionally still see items for peanuts and extortionate > shipping costs, the seller then only has to refund you a couple of dollars > on an item that may have cost you a hundred including shipping. > > I ended up getting a total refund of £3 on a £28 item once I'd returned > it and taken shipping into account. Also, that was a PayPal refund, not a > seller refund because they just refused shipment so eBay refused to refund > as they had no proof of return. > > All the above are the reasons why I now rarely if ever buy anything costing > more than a couple of pounds from China unless I know other people have had > good experience with the item and seller. > On 10 Jul 2016 05:46, "Chris Albertson" wrote: > > > On Sat, Jul 9, 2016 at 5:51 PM, Richard W. Solomon > > wrote: > > > > > What a deal, if it arrives DOA, return shipment is on > > > your nickel. I would look elsewhere. > > > > > > That is not true. If it were DOA and the seller would not take it back > > post paid you could file a "not as described" on the seller and eBay > would > > refund the price. eBay and Paypal offer pretty good buyer protection. > > > > Someone here said the seller uses multiple IDs. It is more likely that > one > > person is making these and offering to multiple people who then sell > them > > on eBay. This is the way it works in China, a popular design gets made > > and then is sold by many people. It is all a cottage industry over > there. > >Pick any kind of electronic PCB level part, say a stepper motor driver > > and you see the same exact part from 20 different sellers not one seller > > with 20 IDs.(Well that is the general case, this specific one might > be > > different, who knows.) > > > > But so what even if the GPSDO is good only to 1xE10 that is still a very > > useful device to own. Yes some are literally 1,000 times better > > > > You could always build your own. It is not hard nor is it expensive if > you > > have a reasonable goal and don't go for state of the art. > > -- > > > > Chris Albertson > > Redondo Beach, California > > ___ > > 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. > -- Chris Albertson Redondo Beach, California ___ 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] Good GPSDO on eBay?
Hi The EEVB guys have been going around on these GPSDO’s for about a year now. Lots of people have tried to get refunds on them. Pretty much every trick in the book (replacement is in the mail …. need one more piece of information from you … shipping clerk in the hospital with bubonic plague …) seems to have been used. If the tricks work, they run you past the refund period stated and … poof … no refund. We often jump on auction site sellers for some pretty minor things. That tends to turn this into a “they are all crooks” sort of discussion. A number of these guys do indeed care about selling stuff. The do indeed honor their warranty. They stay in business under the same name for years and years. Those are the good guys. There *is* a difference. Bob > On Jul 10, 2016, at 12:36 AM, Chris Albertson > wrote: > > On Sat, Jul 9, 2016 at 5:51 PM, Richard W. Solomon > wrote: > >> What a deal, if it arrives DOA, return shipment is on >> your nickel. I would look elsewhere. > > > That is not true. If it were DOA and the seller would not take it back > post paid you could file a "not as described" on the seller and eBay would > refund the price. eBay and Paypal offer pretty good buyer protection. > > Someone here said the seller uses multiple IDs. It is more likely that one > person is making these and offering to multiple people who then sell them > on eBay. This is the way it works in China, a popular design gets made > and then is sold by many people. It is all a cottage industry over there. > Pick any kind of electronic PCB level part, say a stepper motor driver > and you see the same exact part from 20 different sellers not one seller > with 20 IDs.(Well that is the general case, this specific one might be > different, who knows.) > > But so what even if the GPSDO is good only to 1xE10 that is still a very > useful device to own. Yes some are literally 1,000 times better > > You could always build your own. It is not hard nor is it expensive if you > have a reasonable goal and don't go for state of the art. > -- > > Chris Albertson > Redondo Beach, California > ___ > 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] Good GPSDO on eBay?
No, my experience with Chinese sellers, even when you file a "not as described" case, is that eBay will require you to return the item at your own expense if the seller has stated they will not pay return shipping. Ebay's attitude was that the seller could just state in their item description that buyer is to cover return costs and that's it. Game over. Which is why you occasionally still see items for peanuts and extortionate shipping costs, the seller then only has to refund you a couple of dollars on an item that may have cost you a hundred including shipping. I ended up getting a total refund of £3 on a £28 item once I'd returned it and taken shipping into account. Also, that was a PayPal refund, not a seller refund because they just refused shipment so eBay refused to refund as they had no proof of return. All the above are the reasons why I now rarely if ever buy anything costing more than a couple of pounds from China unless I know other people have had good experience with the item and seller. On 10 Jul 2016 05:46, "Chris Albertson" wrote: > On Sat, Jul 9, 2016 at 5:51 PM, Richard W. Solomon > wrote: > > > What a deal, if it arrives DOA, return shipment is on > > your nickel. I would look elsewhere. > > > That is not true. If it were DOA and the seller would not take it back > post paid you could file a "not as described" on the seller and eBay would > refund the price. eBay and Paypal offer pretty good buyer protection. > > Someone here said the seller uses multiple IDs. It is more likely that one > person is making these and offering to multiple people who then sell them > on eBay. This is the way it works in China, a popular design gets made > and then is sold by many people. It is all a cottage industry over there. >Pick any kind of electronic PCB level part, say a stepper motor driver > and you see the same exact part from 20 different sellers not one seller > with 20 IDs.(Well that is the general case, this specific one might be > different, who knows.) > > But so what even if the GPSDO is good only to 1xE10 that is still a very > useful device to own. Yes some are literally 1,000 times better > > You could always build your own. It is not hard nor is it expensive if you > have a reasonable goal and don't go for state of the art. > -- > > Chris Albertson > Redondo Beach, California > ___ > 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] Good GPSDO on eBay?
Mark wrote: Charles, You are confusing these units with those made by that ham in China (can't remember his callsign, begins with a "B"). The guts of these boxes is a telco GPDDO board made by either Trimble or Symmetricom (you can tell because of the 6.0V power requirement).And that reference to a Thunderbolt in his Ebay listing seems to refer to him comparing the output of these to his Thunderbolt, not that the oscillator in them came out of a Thunderbolt. Thanks, Mark, I stand corrected. That also means it will have a PLL, not an FLL. How good is the OCXO? Can you adjust the loop tuning parameters for best stability with the individual OCXO? If not, does the loop cross over from the OCXO to the GPS at an appropriate tau, or does it exhibit the notorious "crossed over too early" hump in the xDEV plots? Does it store its surveyed location or does it need to do a new survey every time it is powered up? Finally, is there a good reason to pay $160 for one the seller has put in a box, or can you buy the board for much less and do that yourself? Best regards, Charles ___ 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] Good GPSDO on eBay?
Michael wrote: I think what the seller saying is that the counter was externally referenced to the Thunderbolt for the frequency measurements that they state. Yes, on re-reading the listing, I believe you are right. Thanks! Charles ___ 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] Good GPSDO on eBay?
On Sat, Jul 9, 2016 at 5:51 PM, Richard W. Solomon wrote: > What a deal, if it arrives DOA, return shipment is on > your nickel. I would look elsewhere. That is not true. If it were DOA and the seller would not take it back post paid you could file a "not as described" on the seller and eBay would refund the price. eBay and Paypal offer pretty good buyer protection. Someone here said the seller uses multiple IDs. It is more likely that one person is making these and offering to multiple people who then sell them on eBay. This is the way it works in China, a popular design gets made and then is sold by many people. It is all a cottage industry over there. Pick any kind of electronic PCB level part, say a stepper motor driver and you see the same exact part from 20 different sellers not one seller with 20 IDs.(Well that is the general case, this specific one might be different, who knows.) But so what even if the GPSDO is good only to 1xE10 that is still a very useful device to own. Yes some are literally 1,000 times better You could always build your own. It is not hard nor is it expensive if you have a reasonable goal and don't go for state of the art. -- Chris Albertson Redondo Beach, California ___ 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] Good GPSDO on eBay?
To paraphrase a few other folks, taking on the task of building your own, even using the VE2ZAZ board as a basis is a very educational experience. It will teach you an enormous amount. There are lessons in control systems, phase and frequency locked loops, oven controllers, phase and frequency measurement, and doubtless lots of things I've overlooked. Well worth the effort. > On Jul 9, 2016, at 23:06, Bob Stewart wrote: > > But, as a starter GPSDO, probably anything is good. Frequency accuracy, even > if a fraction of a Hz off, is all you're looking for at first. I bought one > of Bert Zauhar's (VE2ZAZ) circuit boards and chips for my first one. It was > a good experience. And when I was done, I had a GPSDO that was as good as > most of what you find on ebay in the bargain basement, but at a much lower > cost. But then you need a case, and something to compare it to, and > something even better, and then you're a time-nut. > > But > > > At 04:40 PM 7/9/2016, Richard Mogford wrote: >> This looks like a good beginner's GPSDO on eBay: 172148560746 >> >> "This is GPS Disciplined Clock made with trimble GPSDO Board.Full >> tested by Agilent 53132A with US-012 option and Ex-ref from trimble >> thunderbolt GPSDO." >> >> >> The seller says it has a sine wave output and is accurate from >> 10e-11 to 10e-12. >> >> Any thoughts? >> >> Richard >> >> ___ >> 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.
Re: [time-nuts] Good GPSDO on eBay?
And when you build your own, you're still left with the issue of the oscillator. In my experience, only about 2 out of 3 of the 34310-Ts I get from China are worth using. If you buy them one at a time your odds aren't good. OTOH, as your first oscillator, especially for HF use, noise and stability aren't quite as important as if you're multiplying up to microwaves. But, as a starter GPSDO, probably anything is good. Frequency accuracy, even if a fraction of a Hz off, is all you're looking for at first. I bought one of Bert Zauhar's (VE2ZAZ) circuit boards and chips for my first one. It was a good experience. And when I was done, I had a GPSDO that was as good as most of what you find on ebay in the bargain basement, but at a much lower cost. But then you need a case, and something to compare it to, and something even better, and then you're a time-nut. But one thing to remember Richard, is that the time-nuts idea of accuracy is much different from what you may be used to. For HF ham use,+/- 1Hz accuracy is a big deal. In the time nuts community, phase accuracy to the nanosecond level (and even better, if possible!) is what's important. Bob - AE6RV.com GFS GPSDO list: groups.yahoo.com/neo/groups/GFS-GPSDOs/info From: Dimitri.p To: Discussion of precise time and frequency measurement ; time-nuts@febo.com Sent: Saturday, July 9, 2016 9:14 PM Subject: Re: [time-nuts] Good GPSDO on eBay? since you asked ... Many thoughts, none of them good. Recycled components sold for real money. Too many "versions" to figure out "what you got". If all you want is a frequency standard to turn it on and "forget it" spend a few extra bucks and get one with all new components from a domestic company. Or if you want to have some fun put together one of your own. At 04:40 PM 7/9/2016, Richard Mogford wrote: >This looks like a good beginner's GPSDO on eBay: 172148560746 > >"This is GPS Disciplined Clock made with trimble GPSDO Board.Full >tested by Agilent 53132A with US-012 option and Ex-ref from trimble >thunderbolt GPSDO." > > > The seller says it has a sine wave output and is accurate from > 10e-11 to 10e-12. > >Any thoughts? > >Richard > >___ >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] Good GPSDO on eBay?
Richard wrote: This looks like a good beginner's GPSDO on eBay: 172148560746 "This is GPS Disciplined Clock made with trimble GPSDO Board.Full tested by Agilent 53132A with US-012 option and Ex-ref from trimble thunderbolt GPSDO." The seller says it has a sine wave output and is accurate from 10e-11 to 10e-12. Any thoughts? It is very hard to say exactly what you will get, because the seller (who uses a dozen or more different ebay IDs) seems to change the design every time the wind shifts. But typically they are FLLs (frequency locked loops), not genuine PLLs (phase locked loops), and have a small frequency offset because the design does not address some systemic issues of FLL design. It is unlikely to deliver better than 10e-11 performance with any certainty. In addition to that, if "Ex-ref from trimble thunderbolt GPSDO" is supposed to make a buyer think it will have the best Trimble OCXO (P/N 37265), the one that was in the Trimble Thunderbolts of list legend, that is almost certainly false. It may have a Trimble-branded OCXO, but even if it does it will be one of the many lesser part numbers. To me, the attempts to mislead buyers is enough, by itself, to rule out dealing with that seller, under any of his ebay IDs. Best regards, Charles ___ 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] Good GPSDO on eBay?
since you asked ... Many thoughts, none of them good. Recycled components sold for real money. Too many "versions" to figure out "what you got". If all you want is a frequency standard to turn it on and "forget it" spend a few extra bucks and get one with all new components from a domestic company. Or if you want to have some fun put together one of your own. At 04:40 PM 7/9/2016, Richard Mogford wrote: This looks like a good beginner's GPSDO on eBay: 172148560746 "This is GPS Disciplined Clock made with trimble GPSDO Board.Full tested by Agilent 53132A with US-012 option and Ex-ref from trimble thunderbolt GPSDO." The seller says it has a sine wave output and is accurate from 10e-11 to 10e-12. Any thoughts? Richard ___ 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] Good GPSDO on eBay?
"Full tested by Agilent 53132A with US-012 option and Ex-ref from trimble thunderbolt GPSDO." I think what the seller saying is that the counter was externally referenced to the Thunderbolt for the frequency measurements that they state. Cheers Michael On Sun, Jul 10, 2016 at 10:58 AM, Charles Steinmetz wrote: > Richard wrote: > >> This looks like a good beginner's GPSDO on eBay: 172148560746 >> >> "This is GPS Disciplined Clock made with trimble GPSDO Board.Full tested >> by Agilent 53132A with US-012 option and Ex-ref from trimble thunderbolt >> GPSDO." >> >> The seller says it has a sine wave output and is accurate from >> 10e-11 to 10e-12. >> >> Any thoughts? > > > It is very hard to say exactly what you will get, because the seller (who > uses a dozen or more different ebay IDs) seems to change the design every > time the wind shifts. But typically they are FLLs (frequency locked loops), > not genuine PLLs (phase locked loops), and have a small frequency offset > because the design does not address some systemic issues of FLL design. It > is unlikely to deliver better than 10e-11 performance with any certainty. > > In addition to that, if "Ex-ref from trimble thunderbolt GPSDO" is supposed > to make a buyer think it will have the best Trimble OCXO (P/N 37265), the > one that was in the Trimble Thunderbolts of list legend, that is almost > certainly false. It may have a Trimble-branded OCXO, but even if it does it > will be one of the many lesser part numbers. > > To me, the attempts to mislead buyers is enough, by itself, to rule out > dealing with that seller, under any of his ebay IDs. > > Best regards, > > Charles > > > > ___ > 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] Good GPSDO on eBay?
What a deal, if it arrives DOA, return shipment is on your nickel. I would look elsewhere. 73, Dick, W1KSZ -Original Message- From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Richard Mogford Sent: Saturday, July 09, 2016 4:40 PM To: time-nuts@febo.com Subject: [time-nuts] Good GPSDO on eBay? This looks like a good beginner's GPSDO on eBay: 172148560746 "This is GPS Disciplined Clock made with trimble GPSDO Board.Full tested by Agilent 53132A with US-012 option and Ex-ref from trimble thunderbolt GPSDO." The seller says it has a sine wave output and is accurate from 10e-11 to 10e-12. Any thoughts? Richard ___ 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] Good GPSDO?
You will find most if all of these units are using a Trimble 63090/73090/65256. You will find a lot of good information on this EEVBLOG forum board http://www.eevblog.com/forum/testgear/bg7tbl-gpsdo-master-reference/ if by chance it is a Symmetricom then http://www.eevblog.com/forum/projects/a-look-at-my-symmetricom-gpsdo-(ocxo-furuno-receiver)/ As for spec and how good these are I own a the Symmetricom but don't have the equipment and more importantly the knowledge to test or give advice to others. Will defer that to the experts on Time-Nuts. p.s. if you search eBay for the Trimble with the mfg. numbers as I mentioned you will find them a lot cheaper if you want to roll out your own. -=Bryan=- > From: rch...@earthlink.net > Date: Sat, 2 Jul 2016 21:28:12 -0700 > To: time-nuts@febo.com > Subject: [time-nuts] Good GPSDO? > > I am just getting into the precise time and frequency stuff. I thought I > should buy a GPSDO. > > There are quite a few similar-looking ones on eBay, such as eBay number > 281802105734 > > There is also a Trimble at 252162780444 > > Would either of these be OK for a newbie like me? > > Richard > ___ > 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] Good GPSDO?
I am just getting into the precise time and frequency stuff. I thought I should buy a GPSDO. There are quite a few similar-looking ones on eBay, such as eBay number 281802105734 There is also a Trimble at 252162780444 Would either of these be OK for a newbie like me? Richard ___ Richard, You might also look at a rather more versatile product - Leo Bodnar's Precision Frequency Reference (GPS Clock): http://www.leobodnar.com/shop/index.php?main_page=product_info&products_id=234 with multiple programmable frequency outputs. I have one of these and find it quite handy. For a fixed frequency board-level product, the LTE-Lite Evaluation Board: http://www.jackson-labs.com/index.php/products/lte_lite The Trimble stuff is rather dated now, and uses fewer satellites than the more recent units. Cheers, David -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ 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.