GPSDXO 40/10MHz - Page 1
Forum section: electronics / testgear

author: mawyatt
author_rank: Super Contributor
timestamp: November 06, 2020, 04:21:35 pm
content: Any comments/experience on this GPS receiver for use as a frequency reference, available on Tindie?https://www.tindie.com/products/tobiw/gps-disciplined-4010mhz-frequency-source-0001ppm/Best,

author: noreply
author_rank: Frequent Contributor
timestamp: November 06, 2020, 06:20:19 pm
content: Looks Good - unfortunately I have not seen this unit before.I have a BG7TBL GPSDO - paid GBP120 - delivered from China via AmazonThe BG7TBL GPSDO has been performing rock solid for me - 0.0006182 Hz trackingYour unit looks like its sharing the 'generic' extruded aluminum casing - but does not have a serial port.The price is very good and in my opinion worth a 'try'If its true to the spec sheet - it will be a good buy

author: mawyatt
author_rank: Super Contributor
timestamp: November 06, 2020, 06:40:21 pm
content: Quote from: noreply on November 06, 2020, 06:20:19 pmNot sure what type of OX this unit has, but indicates a "new" TCXO and MT3333 chip set.Just checked and your BG7TBL appears to have a OCXO, is this true?Best,

author: tautech
author_rank: Super Contributor
timestamp: November 06, 2020, 09:30:10 pm
content: Leo does some nice stuff:http://www.leobodnar.com/shop/index.php?main_page=index&cPath=107http://www.leobodnar.com/shop/index.php?main_page=index&cPath=122

author: noreply
author_rank: Frequent Contributor
timestamp: November 06, 2020, 09:58:41 pm
content: Quote from: mawyatt on November 06, 2020, 06:40:21 pmYes it certainly does - the OCXO's are 'used' which are ex-service from 2G GSM base station equipment - pre FPGA designs - so they literally had to scrap the system to upgrade to 4G rather than simply update the firmware.They have relatively low hours - and are in effect 'burned-in' so quite stable.here is link to one of my 'old' posts ...https://www.eevblog.com/forum/testgear/bg7tbl-gpsdo-master-reference/msg3240758/#msg3240758I guess the unit you are looking at - does not have a OCXO - that's probably why its lower cost.Hope the above info is helpfulTake Care

author: tkamiya
author_rank: Super Contributor
timestamp: November 07, 2020, 06:49:41 am
content: One thing that concerns me is clear definition of what data the unit can send to PC. It simply states "send current deviation" but what does that mean? Just a text string of how far the signal is off? How do you know how many satellite it is tracking? How strong are signals?I have several GPSDO. All of them have some means to send full data to PC. Some does NEMA, some are Trimble proprietary, some are even some other standard. But all, with right software like "Lady Heather", it can show me full information - graphs and table included. It gives me a good measure of assurance that I am actually synced to GPS.I also see back panel doesn't say 10MHz anywhere? Most lab equipment require 10MHz, some older ones does 5MHz, some do multiple.... This is not a "review" as I don't know this equipment. But I see more shortcoming than benefit.

author: thinkfat
author_rank: Unknown
timestamp: November 07, 2020, 08:52:11 am
content: The specs don't look very impressive. Certainly there's no OCXO inside if you look at the power consumption, therefore stability will be not very good at low tau.Accurate to 1e-9 is OK-ish but not great. Phase noise -60dBc at 10Hz - are they afraid to give a number for 1Hz?Harmonic suppression -40dB at 10MHz - I bet they're using a VCTCXO with square wave output and a low-order Bessel or Butterworth lowpass filter to make a sine wave.Honestly, buy Leo's mini precision GPS source, it is at least one order of magnitude more stable and less noisy, plus you get a programmable DDS output.