I've been playing around with a working prototype of the Huawei WD22UGRC (u-blox LEA-M8T) - sourced from eBay
Paired this with Waveshare RS-232 board and a RF Solutions ANT-GPSC-SMA (Active GPS/GLONASS antenna, 3.3-5.0v) - sourced from Electropeak
And a SMA to SMB Coax Adapter SMA Female to SMB Female RF Coaxial Connector - sourced from Amazon
Powered by a 3.3v supply (drawing only 0.03 amps)
Designed an enclosure for the Huawei WD22UGRC in Solidworks and 3d printed
Utilized M3 heat set inserts from McMaster Carr
Timing and PPS from the Huawei WD22UGRC is converted from TTL/CMOS 3.3v levels to RS-232 12v levels - and can be fed into any COM port on your PC.
The Waveshare RS-232 board was chosen because of the below attributes
SP3232 chip allows for (4) channels - RX, TX, CTS, and RTS - (3) of these channels are needed for NTP timekeeping - RX (receiving NMEA sentences), TX (programming), and CTS (receiving PPS)
Operates at same voltage as Huawei WD22UGRC (3.3v)
Detailed 3d model available showing exact placement of mounting holes (1 hole is slightly offset, not symmetrical)
Likewise, the RF Solutions ANT-GPSC-SMA active antenna was also chosen because it operates at same voltage as Huawei WD22UGRC (3.3v)
Kind of an alternative to the PPS Piggy
https://partiallystapled.com/hardware/pps_piggy/