But we got them before the prices skyrocketed (Back then it was $110 for a unit , and $200 for a kit)
WOW $110 for a GPSDO, that would have been great. Sadly I panicked about a FE5680A at $89 (free shipping) on ebay and already bought one, the next cheap one is about $120 (incl. shipping). At least the seller claims it's one of the latest UN-7XXXXX models available from eBay with 2004 manufacturing date. Having bought the counter and the rubidium standard, I have left about 30-40 bucks.
How difficult could it be to later make a GPSDO using this FE5680A and a GPS receiver with 1 PPM output? Any place to start reading the basics about how to do it?
Is there any GPS receiver unit recommended for this? Maybe I can afford a cheap one.
Anyway, I hope the OCXO in the HP counter is working good, seller claimed last calibration was in 2010, but cannot trust him because he doesn't seem knowledgeable about test equipment, he mainly sells used low end audio stuff.
WOW $110 for a GPSDO, that would have been great. Sadly I panicked about a FE5680A at $89 (free shipping) on ebay and already bought one, the next cheap one is about $120 (incl. shipping). At least the seller claims it's one of the latest UN-7XXXXX models available from eBay with 2004 manufacturing date. Having bought the counter and the rubidium standard, I have left about 30-40 bucks.
How difficult could it be to later make a GPSDO using this FE5680A and a GPS receiver with 1 PPM output? Any place to start reading the basics about how to do it?
Is there any GPS receiver unit recommended for this? Maybe I can afford a cheap one.
Anyway, I hope the OCXO in the HP counter is working good, seller claimed last calibration was in 2010, but cannot trust him because he doesn't seem knowledgeable about test equipment, he mainly sells used low end audio stuff.
FE5680A is good but it is not easy to trim to correct frequency.
http://www.ko4bb.com/dokuwiki/doku.php?id=precision_timing:fe5680a_faqNow you need also GPSDO and your counter to check this FE5680A.
You can do GPSDO yourself or buy a kit:
http://www.jrmiller.demon.co.uk/projects/ministd/frqstd0.htm
I've got one of those HP Z3805A units. It works flawlessly and has many outputs, including Rs232. They used to cost a lot more (around $400) a few years ago before a truckload of thunderbolts appeared. I think it's a bargain at the current price.
3805 usually sold without an antenna but it Works with most "active" gps pucks. It may show an alarm light because the new antennas draw very little current and the device thinks it's unplugged. The trick is to add a resistor between the center conductor and ground of the coax connector. Don't believe this affects the accuracy. Don't forget the setting for coax propagation delay which based on the cable length and velocity factor. a guesstimate is probably ok here