Anyone tried out the TM5301A? - Page 1
Forum section: electronics / testgear

author: Tapioca Pudding
author_rank: Newbie
timestamp: December 13, 2020, 09:28:08 pm
content: I need a new GPSDO for my homelab. I was looking around on eBay for used equipment and came across the TM5301A, seems new. Has anyone tried this or can link a review? Thanks in advance!Ebay Link:https://www.ebay.com/itm/TM5301A-GPSDO-GPS-Disciplined-Oscillator-Color-Display-Accuracy-For-GPS-Beidou/174387570327

author: tautech
author_rank: Super Contributor
timestamp: December 14, 2020, 01:12:34 am
content: Welcome to the forum.Seems expensive compared to member Leo Bodnar's GPSDO offerings:http://www.leobodnar.com/shop/index.php?main_page=index&cPath=107&zenid=a63104ee7b1350bae9838b944664a40e

author: Tapioca Pudding
author_rank: Newbie
timestamp: December 14, 2020, 01:50:57 am
content: Thanks for the recommendation (and greeting), I'll take a look.I'm looking for something that will output a 10 MHz square and PPS. Monitoring is a plus. Both will get distributed to some SDRs and test equipment.

author: burkm
author_rank: Regular Contributor
timestamp: June 07, 2021, 08:48:39 pm
content: To restart an older thread: The TM 5301A doesn't seem to have any reviews yet. Main argumentsfor:- fast startup time until it reaches rather good stability- low phase noise if one trusts the published data- 2x sine and square wave outputs- multi color display with lost of informations- high default baud rate for data. Against: no info about the OCXO used, no infp about the inards of that black box, rather high price in comparison.against:- only GNSS GPS and Beidou satellite networks seem to be supported- no info about XO or OCXO installed- no info about the innards of unit- rather high price in comparison- not very popular ist seems

author: linearaudio
author_rank: Newbie
timestamp: July 15, 2021, 07:30:05 pm
content: Just received my TM5301A from:https://www.ebay.de/itm/283997524624?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649For an additional US $ 48,- an U-blox NEO M8T GNNS receiver was installed, capable of GPS, GLONASS, GALILEO & BEIDOU,a sensitive receiver with 72 channels from Swiss company U-blox.Fast lock, 3 concurrent GNSS, really a nice unit, came with power supply and indoor active GPS & BEIDOU antenna. You will want to usean active outdoor antenna with this GNSS receiver, Navilock NL-250GG is an appropriate unit covering all four GNSS.I also tried another GPS only receiver, based on an old, used Symmetricom module:https://www.ebay.de/itm/143319767716?hash=item215e861aa4:g:Q34AAOSwouNgcDBrI will return this receiver, does not lock even after more than one hour, using the same antenna that works perfectly with the TM5301A !My advice: stay off the China made GNSS receivers using old, recycled and insensitive receivers. Same model is available with old Samsungor Trimble receiver as well.ADEV of TM5301A is really good, so this GNSS receiver is suitable as a timebase for my Pendulum CNT-90 and CNT-91 counters, see attachment.I think the TM5301A, made from all new components ( I opened it ), is worth the money asked.Yngve

author: Tapioca Pudding
author_rank: Newbie
timestamp: July 20, 2021, 10:53:31 pm
content: Thanks for the post. Those are good results, linearaudio! What timebase did you use to measure the ADEV with, your CNT-91 internal or a house clock? Would you mind sharing a photo of the inside? I'm curious about the OCXO they used.I ended going with a used GRClok-1500 from SpectraTime - it's a rubidium GPSDO that was being used for in an IEEE-1588 Ethernet adapter. I needed something better than 1e-10@1s, so this fit the bill.https://www.orolia.com/sites/default/files/document-files/isync_lnr_grclok_1500_manual_1.pdf

author: linearaudio
author_rank: Newbie
timestamp: July 26, 2021, 02:27:07 pm
content: The ADEV data published are from the Chinese vendor. The OCXO is a single oven model, so temperature and aging performance are not as good as on a DOCXO. The type of the OCXO is kept as a trade secret, no type numer on the OCXO. But as I learned from the vendor, the unit uses Kalman filtering. That is, it tracks the temperature and aging behavior of the OXCO, like on the vintage TRIMBLE Thunderbolt GPS unit. When there is no satelite reception, the DAC output voltage controlling the OCXO is not simply kept constant for the hold over period, it is altered according to the measured temperatue and the learned aging parameters. Really an oustanding Chinese product, not the usual "POORLY MADE IN CHINA" quality. Also, sideband noise performance is quite good, check the ebay link for data.Yngve

author: syau
author_rank: Frequent Contributor
timestamp: July 28, 2021, 11:20:56 pm
content: Quote from: linearaudio on July 15, 2021, 07:30:05 pmWas the M8T install by the seller or DIY ? If DIY, could you please share the necessary information especially the configuration required by u-center.

author: syau
author_rank: Frequent Contributor
timestamp: August 05, 2021, 12:13:43 am
content: Just received my unit, the sensitivity of the GPS/Badiu receiver is very good, positioning is very fast. Will do a comparison with Star 4 and my Rubidium atomic clock later.

author: linearaudio
author_rank: Newbie
timestamp: August 05, 2021, 06:32:13 pm
content: The M8T was installed by the vendor by request for an additional US $ 48,-

author: twwwt
author_rank: Newbie
timestamp: August 07, 2021, 03:30:48 pm
content: QuoteI'm wondering who the vendor of this GPSDO is? I couldn't find this information, neither from the offers on EBay, Aliexpress (where it is also sold by a few stores), nor by googling for the model TM5301A. Do you have contact information or a web site URL?

author: syau
author_rank: Frequent Contributor
timestamp: August 08, 2021, 02:20:37 pm
content: Only manage to find manufacturer in Taobaohttps://m.tb.cn/h.fZ13MpL?sm=7110d8which is in Chinese only.

author: stewart.nz
author_rank: Newbie
timestamp: January 17, 2023, 08:25:47 am
content: Hi, can someone please suggest what is the best software to communicate with the "TM5301A GPSDO Disciplined Oscillator" via USB please?Stewart

author: stewart.nz
author_rank: Newbie
timestamp: January 17, 2023, 09:15:53 am
content: TM5301A GPSDO Disciplined Oscillator datasheet attached FYI.Stewart

author: emanuele77
author_rank: Newbie
timestamp: September 16, 2025, 09:00:20 am
content: ciao sono Emanuele volevo chiederti se il TM5301A riceve dall'Italia la frequenza con la precisione promessa dall'apparecchio oppure bisogna installare anche il ricevitore U-blox Neo M8T compatibile con GPS, Glonass, Galileo e Beidou, in questo caso puoi mandarmi il link per acquistare il TM5301A completo di questo ulteriore ricevitore? Se non c'è un link puoi spiegarmi come acquistare un ricevitore completo come il tuo? Grazie ciao Emanuele

author: picburner
author_rank: Frequent Contributor
timestamp: September 21, 2025, 10:51:30 am
content: Has anyone who purchased this GPSDO tried and succeeded in changing the UTC time zone?The listing says it's set to UTC +8 by default, but the seller told me it's not possible to change this setting and the device is set to UTC +0.It seems absurd to me that it's not possible to change the time zone.