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 use
an 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 Samsung
or 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