bg7tbl gpsdo master reference

[beanflying]

Until I brought my 'first' Frequency counter and had a fairly average Signal Generator at the time I 'needed' a reliable reference to set the counter and know how far the Feelcrud was off from what it showed. That was a much better Generator and several more Counters ago now

The reality is that most users have about Zero need for a GPSDO and if it wasn't for the 10Meg gitter of the UBlox then one of these would do fine for 95-98% of us as a sort of ok reference. If all we need is a way to set another device then a 5:4 Lissajous with the UBlox supplying an 8Meg against an unknown near 10Meg device would get the job done for just a few $.

This does not in anyway apply to Time Nuts or those who have a need for sub Hertz resolution but the reality is that is the nerdy fringe (I aspire to this  )

[burkm]

I don't think, that I (or anyone) should judge any user by his "needs", because I don't know them and wouldn't dare to extrapolate this from the "outside"...
For what reason he has bought it, is not to be decided by myself...
But he should get, what has been "promised" for the advertised items, at least not less.

[hpw]

just an obvious question...

how is the GPS sync done

. by phase as PLL

. by frequency compare

[burkm]

As far as i have concluded from several threads about the BG7TBL GPSDO / GNSSDO, it is done by PLL.

[hpw]

As far as i have concluded from several threads about the BG7TBL GPSDO / GNSSDO, it is done by PLL.

At what freq. runs the PLL .. ?

[lachesis]

I have a version of this labeled 2019-08-09 on the case. I bought it back in late 2019 or early 2020, but I had a cross-country move and didn't get around to playing with it until now. I can confirm that the PPS signal is 3.3V. The serial on this board uses a 3.5mm audio jack, with TX on tip and RX on ring. The serial doesn't seem to output NUMA. I have tried three serial adapters. One is DB9 to USB, presumably tolerant of +/- 12V "true" RS232. Another just has 4 pins to USB, 3.3/5V serial. Finally, I tried the UART0 on my Raspberry Pi. The first two adapters report nothing (so probably something wrong with my cable) but using a different cable with the RPi UART, I get a stream of binary nonsense every second, about 5120 bytes per transfer, at 9600 baud. None of the other baud rates I tried did any better. The GPSDO otherwise behaves normally. It boots with PWR flashing and ALRM lit, then goes to both solid, then just PWR green solid after a few minutes of running.

Here's a hex dump of the data that I'm reading.

00000000: 3c0e cece 3ece cef0 cef0 8c30 3ef0 fef0  <...>......0>...
00000010: fef0 3ef0 ce0c 8cc0 3e3e f0fe f0fe 308c  ..>.....>>....0.
00000020: cc30 0ef0 cec0 cef0 ce0e 3c3e 3ece 0e0e  .0........<>>...
00000030: f00e f0fe 80fc 303e ce30 fef0 fec0 fc0c  ......0>.0......
00000040: cef0 fec0 3e3e 3e3e f00c f0ce 0e0e f0fe  ....>>>>........
00000050: 300e cefc 30fe f03e 3efe f0ce f03e f0fc  0...0..>>....>..
00000060: 30fe 30fe f0ce 0efe f0ce 803c f0ce f0fe  0.0........<....
00000070: 30fe 30fe 30fc fcce ce3e 30fe c0ce f03e  0.0.0....>0....>
00000080: fcfc 3c0e cece 3ece fece ce80 8c30 fe30  ..<...>......0.0
00000090: fece ce30 fe30 8cf0 ce30 fef0 3e3e fef0  ...0.0...0..>>..
000000a0: cef0 3cf0 fe30 3ece 30fe f03c 3c3e fef0  ..<..0>.0..<<>..
000000b0: 0ef0 fe30 0e3e fc30 fefe cece 3e3e cef0  ...0.>.0....>>..
000000c0: cef0 3cfe fe3e 0ece ce0e 8c80 cefe ce30  ..<..>.........0
000000d0: 3ef0 fef0 fef0 3cf0 ce0e cec0 3e3e f0fe  >.....<.....>>..
000000e0: f0fc 300e f0ce c0ce f0ce 0e3c 3e3e ce0e  ..0........<>>..
000000f0: 0ef0 0ef0 fe80 fc30 3ece 30fe f0fe c0fc  .......0>.0.....
00000100: 0cce f0fe c03e 3e3e 3ef0 0cf0 ce0e 0ef0  .....>>>>.......
00000110: fe30 0ece fe30 3cf0 fe30 fef0 cec0 fe30  .0...0<..0.....0
00000120: 8cf0 3e3e 3efe f0fe 303e f03c f0fe 0e3e  ..>>>...0>.<...>
00000130: 3ef0 fe30 8cf0 cc30 ce30 0ef0 0ef0 3e3c  >..0...0.0....><
00000140: f0f0 fe30 cef0 ce30 fe30 fef0 fcf0 fef0  ...0...0.0......
00000150: fef0 3ece 3ef0 3ccc 0e3e fefe 3e0e ce8c  ..>.>.<..>..>...
00000160: 0cce f0ce cece 30ce ce30 0cf0 fe30 cef0  ......0..0...0..
00000170: fec0 fe30 3cf0 0ef0 fe30 cef0 ce0e fe30  ...0<....0.....0
00000180: 3cf0 fe0e fe30 ce0e cef0 fc30 cef0 fef0  <....0.....0....
00000190: fe30 cef0 0ef0 fc30 fe0e 3ef0 fe30 0ef0  .0.....0..>..0..
000001a0: 3ef0 fc30 fe30 fe30 fe30 3ef0 3c3c 0e3e  >..0.0.0.0>.<<.>
000001b0: f0fe 30ce f03e 3c3c fef0 fe30 3ef0 3e3e  ..0..><<...0>.>>
000001c0: fcf0 fc0e 3ece fef0 fec0 cef0 3cfc fe3e  ....>.......<..>
000001d0: 0ece ce0e cef0 8c3c cefe 30fe 0efe 30ce  .......<..0...0.
000001e0: f0fc 30ce f00e f0fe 30fe f0ce 0efc 30fe  ..0.....0.....0.
000001f0: f0ce 0efe 30fe f0ce 800c f0fe 30fe 30fe  ....0.......0.0.
00000200: f0fe c0fc 30fe f03e f0fe 300e f03e f0fc  ....0..>..0..>..
00000210: 0cfe 30fe 30ce f0fe f0fe 30fc 0e3e f0fe  ..0.0.....0..>..
00000220: 300e f0fe f08c f0fe 303e f0ce 0efe 30ce  0.......0>....0.
00000230: f00c f0fe 30fe f0fe c0fe 30fc f0fe 0e0e  ....0.....0.....
00000240: f0fe 30fe f0fe c03c cc0e f0fe c0ce f03e  ..0....<.......>
00000250: fefe 3c0c cece 0ece f0ce 3ece fc30 fe0e  ..<.......>..0..
00000260: fe30 3ef0 fe30 cef0 0cf0 fe30 cef0 ce0e  .0>..0.....0....
00000270: fe30 0ef0 3cf0 fe30 fef0 ce0e 0ef0 fc30  .0..<..0.......0
00000280: 3ef0 cef0 fe30 cef0 fe80 fc30 3ef0 fec0  >....0.....0>...
00000290: fe30 cef0 0cf0 3ef0 fe30 0ef0 3ef0 fe30  .0....>..0..>..0
000002a0: 3cf0 0ef0 fe30 3ef0 cec0 fe30 0cf0 ce0e  <....0>....0....
000002b0: fef0 fe30 3ef0 fc80 fe30 3ef0 fe0e fe30  ...0>....0>....0
000002c0: fe0c 8cc0 fe30 cef0 cef0 fef0 fc30 0ef0  .....0.......0..
000002d0: 3ef0 3ece 0ef0 0ef0 8cf0 3efe fe3e 0ece  >.>.......>..>..
000002e0: ce0e 8cf0 ce3e cefe 30fe 0efe 300c f0fe  .....>..0...0...
000002f0: 30ce f00e f0fe 303e f00c f0fe 303e f0fe  0.....0>....0>..
00000300: f0fe 303e f0cc c0fe c0fe 303e f00e f0fc  ..0>......0>....
00000310: 300e f03e f0fe 303e f03e f0fc 303e f00e  0..>..0>.>..0>..
00000320: f03e f0fe 303c f0ce 0efe 30fe 0e3e f0fe  .>..0<....0..>..
00000330: 303c f0ce 0efe 303e f00e f0fe 80fc 300e  0<....0>......0.
00000340: f0fe f0fe 30fe 0efc 80fe 303e f0fe c0fe  ....0.....0>....
00000350: 303e f00c f0fe 0efe 300e f0ce f03e 8c0c  0>......0....>..
00000360: f03e f0ce f03e fefe 3e0c cece 0ece f0ce  .>...>..>.......
00000370: 3ece fe30 fc0e fe30 fe0e fe30 cef0 0cf0  >..0...0...0....
00000380: fe30 ce0e cef0 fe30 0ef0 8cc0 fe30 3ef0  .0.....0.....0>.
00000390: cef0 fe0e fe30 0cf0 3ef0 3ece fe0e 0ef0  .....0..>.>.....
000003a0: 8cf0 3efe fe3e 0ece ce0e 8cf0 cef0 ce30  ..>..>.........0
000003b0: 0ef0 cec0 cef0 cc0e 3e3e 3ece 0e0e f00c  ........>>>.....
000003c0: f0fe c0fe 303e ce30 fef0 fcc0 fe0e cef0  ....0>.0........
000003d0: fec0 3e3e 3c3e f00e f0ce 0e0e f0fe 300c  ..>><>........0.
000003e0: cefe 303e f0fe f0fe f03e f0cc 0ece c03e  ..0>.....>.....>
000003f0: 3ef0 fef0 fc30 cece 30fe fece ce3e c0f0  >....0..0....>..
00000400: 0cce 0e3e fe00 3e0e 8cce 3ece cef0 cef0  ...>..>...>.....
00000410: ce30 3cf0 fef0 fef0 0ef0 fef0 fef0 3c3e  .0<...........<>
00000420: f0fe f0fe 30ce ce30 0cf0 cec0 cef0 ce0e  ....0..0........
00000430: 3e3c 3cce 0e0e f0fe c0fe f0fe 303c ce30  ><<.........0<.0
00000440: fef0 fec0 fe0e 8cf0 fec0 3e3e 3e3e f00e  ..........>>>>..
00000450: f08c 0c3e f0fe 300e cefe 30fe f03c 3ef0  ...>..0...0..<>.
00000460: 3ef0 ce0e fe30 fc30 fef0 ce0e fef0 cec0  >....0.0........
00000470: 3ef0 8cf0 fe30 fe30 fe30 fefe ce8c 3c30  >....0.0.0....<0
00000480: 3ef0 cef0 3efe fe3e 0cce ce3e cefe cece  >...>..>...>....
00000490: c0ce 30fc 30fe cece 30fe 30ce f0ce 30fe  ..0.0...0.0...0.
000004a0: f03e 3ef0 3ef0 ce0e fc30 3ece 30fe f03e  .>>.>....0>.0..>
000004b0: 3efc f03c f0fe f0fe 300e 3efe 30fc fcce  >..<....0.>.0...
000004c0: ce3e 3e3e f0ce f03e fcfc 3e0e cece 0ece  .>>>...>..>.....
000004d0: c0ce fccc 303e f0fe f0fe f00e f0fc f0fe  ....0>..........
000004e0: f03e 3ef0 fef0 fe30 0cf0 cec0 cef0 ce0e  .>>....0........
000004f0: 3e3e 3cce 0e0e f0fe c0fe f0fe 303c ce30  >><.........0<.0
00000500: fef0 fec0 fe0e cef0 fcc0 3e3e 3e3e f00e  ..........>>>>..
00000510: f08c 0c3e f0fe 300e cefe 303e f0fc 30fe  ...>..0...0>..0.
00000520: f0ce c0fe 30ce f03c 3c3e fef0 fe30 3ef0  ....0..<<>...0>.
00000530: 3ef0 0cf0 3e3e c0fe 30ce f0ce 308c 300e  >...>>..0...0.0.
00000540: f00e f03e 3ef0 f0fc 30ce f0ce 30fe 30fe  ...>>...0...0.0.
00000550: f0fe f0fc f0fe f03e ce3e f03e ce0c 3cfe  .......>.>.>..<.
00000560: fe3e 0ece ce0e 8cf0 ccce ce30 cece 300e  .>.........0..0.
00000570: f0fc 30ce f0fe c0fe 303e f00c f0fe 30ce  ..0.....0>....0.
00000580: f0ce 0efe 303e f0fc 0cfe 30ce 0ece f0fe  ....0>....0.....
00000590: 30ce f0fc f0fe 30ce f00e f0fe 30fc 0c3e  0.....0.....0..>
000005a0: f0fe 300e f03e f0fe 30fc 30fe 30fe 303e  ..0..>..0.0.0.0>
000005b0: f03e 3e0c 3cf0 fe30 cef0 3e3e 3efc f0fe  .>>.<..0..>>>...
000005c0: 303e f03e 3efe f0fe 0c3c cefe f0fe c0ce  0>.>>....<......
000005d0: f03e fefc 3c0e cece 0ece f0ce 3e8c fc30  .>..<.......>..0
000005e0: fe0e fe30 cef0 fe30 cef0 0cf0 fe30 fef0  ...0...0.....0..
000005f0: ce0e fe30 fcf0 ce0e fe30 fef0 cec0 0ef0  ...0.....0......
00000600: fc30 fe30 fef0 fec0 fe30 fef0 3cf0 fe30  .0.0.....0..<..0
00000610: 0ef0 3ef0 fe0e fc30 fe30 cef0 fef0 fe30  ..>....0.0.....0
00000620: fe0c 3cf0 fe30 0ef0 fef0 cef0 fc30 3ef0  ..<..0.......0>.
00000630: ce0e fe30 cef0 0ef0 fc30 fef0 fec0 fe30  ...0.....0.....0
00000640: fef0 fe0c 0cf0 fe30 fef0 fec0 3ece 0cf0  .......0....>...
00000650: fec0 cef0 3efe fe3e 0e8c ce0e cef0 ce3e  ....>..>.......>
00000660: cefe 30fc 0cfe 303e f0fe 30ce f00e f0fc  ..0...0>..0.....
00000670: 30ce f0ce 0efe 300e f03e f0fc 30fe f0ce  0.....0..>..0...
00000680: 0e0e f0fe 303c f0ce f0fe 30ce f0fe c0fe  ....0<....0.....
00000690: 303c f0fe c0fe 30ce f00e f03e f0fc 300e  0<....0....>..0.
000006a0: f03e f0fe 303e f00c f0fe 303e f0ce c0fe  .>..0>....0>....
000006b0: 300e f08c 0efe f0fe 303e f0fe c0fc 303e  0.......0>....0>
000006c0: f0fe 0efe 30fe 0ece c0fc 30ce f0ce f0fe  ....0.....0.....
000006d0: f0fe 300e f03c f03e ce0e f00e f0ce f03c  ..0..<.>.......<
000006e0: fcfe 3e0e cece 0ece f08c 3cce fe30 fe0e  ..>.......<..0..
000006f0: fe30 0ef0 fe30 ccf0 0ef0 fe30 3ef0 0ef0  .0...0.....0>...
00000700: fc30 3ef0 fef0 fe30 3ef0 ce80 fcc0 fe30  .0>....0>......0
00000710: 3ef0 0ef0 fe30 0cf0 3ef0 fe30 3ef0 3ef0  >....0..>..0>.>.
00000720: fe30 3cf0 0ef0 3ef0 fe30 3ef0 fe0c fc30  .0<...>..0>....0
00000730: fe0e 3ef0 fe30 3ef0 8c0c fe30 3ef0 0ef0  ..>..0>....0>...
00000740: fec0 fe30 0cf0 cef0 fe30 fe0e fec0 fe30  ...0.....0.....0
00000750: 3cf0 fec0 fe30 3ef0 0ef0 fc0c fe30 0ef0  <....0>......0..
00000760: fef0 3ece 0ef0 0cf0 cef0 3efe fe3e 0ece  ..>.......>..>..
00000770: 8c0e cef0 ce3e cefe 30fe 0efc 30fe 0efe  .....>..0...0...
00000780: 30ce f00e f0fe 30cc 0ece f0fe 300e f0ce  0.....0.....0...
00000790: c0fc 303e f0ce f0fe 0efe 300e f03c f03e  ..0>......0..<.>
000007a0: cefe 0e0e f0ce f03c fcfc 3e0e cece 0ece  .......<..>.....
000007b0: f08c f0ce 300e f0ce c0ce f0ce 0c3c 3e3e  ....0........<>>
000007c0: ce0e 0ef0 fec0 fcf0 fe30 3ece 30fe f0fe  .........0>.0...
000007d0: 80fc 0cce f0fe c03e 3e3e 3ef0 0cf0 ce0e  .......>>>>.....
000007e0: 3ef0 fe30 0ece fc30 3ef0 fef0 fef0 0ef0  >..0...0>.......
000007f0: fef0 fcf0 3e3e f0fe f0fe 308c cc30 fefe  ....>>....0..0..
00000800: cece 3ec0 f00e f08c f03e fe00 3e0e cece  ..>......>..>...
00000810: 3c8c cef0 cef0 ce30 3ef0 fef0 fcf0 0ef0  <......0>.......
00000820: fef0 cef0 3e3e f0fc f0fe 30ce ce30 0ef0  ....>>....0..0..
00000830: 8cc0 cef0 ce0e 3e3e 3ece 0c0c f0fe c0fe  ......>>>.......
00000840: f0fe 303e ce30 fef0 fec0 fe0e cef0 fec0  ..0>.0..........
00000850: 3c3e 3e3e f00e f0ce 0e0e f0fc 300e cefe  <>>>........0...
00000860: 30fe f03e 3ef0 fe0e ce0e fe30 fe30 fef0  0..>>......0.0..
00000870: 8c0c fef0 cec0 3ef0 cef0 fe30 fc30 fe30  ......>....0.0.0
00000880: fefe cece 3e30 fcf0 cef0 3efe fe3e 0ece  ....>0....>..>..
00000890: 8c3c cefe cece c0ce 30fe 30fc 8ccc 30fe  .<......0.0...0.
000008a0: 30ce f0ce 30fe f03c 3ef0 fe0e ce0e fe30  0...0..<>......0
000008b0: 3e8c 30fe f03e 3ef0 fec0 0cf0 fe30 0e3e  >.0..>>......0.>
000008c0: fe30 fefe cece 3c3c 0ece 0e3e fefe 3e0e  .0....<<...>..>.
000008d0: 8cce 0ece c0ce fece 303c f0fe f0fe f00e  ........0<......
000008e0: f0fe f0ce f03c 3ef0 fef0 fe30 0ef0 8c80  .....<>....0....
000008f0: cef0 ce0e 3e3e 3ece 0e0c f0fe c0fe f0fe  ....>>>.........
00000900: 303e ce30 fcf0 fec0 fe0e cef0 fec0 3c3c  0>.0..........<<
00000910: 3e3e f00e f0ce 0e0e f0fc 300e cefe 303e  >>........0...0>
00000920: f0fe 30fc f0cc c0fe 30ce f03e 3e3e fcf0  ..0.....0..>>>..
00000930: fe30 3ef0 3ef0 0ef0 3e3c c0fe 30ce f0ce  .0>.>...><..0...
00000940: 30ce 300c f00e f03e 3ef0 f0fe 30ce f08c  0.0....>>...0...
00000950: 30fe 30fe f0fe f0fe f0fe f03c ce3e f03e  0.0........<.>.>
00000960: ce0e 3efe fc3c 0ece ce0e cef0 cece 8c30  ..>..<.........0
00000970: cece 300e f0fe 308c f0fe c0fe 303e f00e  ..0...0.....0>..
00000980: f0fe 308c f0ce 0efe 303e f0fe 0efe 308c  ..0.....0>....0.
00000990: 0ece f0fe 30ce f0fe f0fc 30ce f00e f0fe  ....0.....0.....
000009a0: 30fe 0e3e f0fc 300e f03e f0fe 30fe 30fe  0..>..0..>..0.0.
000009b0: 30fc 303e f03e 3e0e 3ef0 fc30 cef0 3e3e  0.0>.>>.>..0..>>
000009c0: 3efe f0fe 303c f03e 3efe f0fe 0e3e cefc  >...0<.>>....>..
000009d0: f0fe c0ce f03e fefe 3e0e 8cce 0ece f0ce  .....>..>.......
000009e0: 3ece fe30 fe0c fc30 cef0 fe30 cef0 0ef0  >..0...0...0....
000009f0: fc30 fef0 ce0e fe30 fef0 ce0e fc30 fef0  .0.....0.....0..
00000a00: cec0 0ef0 fe30 fe30 fcf0 fec0 fe30 fef0  .....0.0.....0..
00000a10: 3ef0 fc30 0ef0 3ef0 fe0e fe30 fe30 8cf0  >..0..>....0.0..
00000a20: fef0 fe30 fe0e 3ef0 fc30 0ef0 fef0 cef0  ...0..>..0......
00000a30: fe30 3ef0 8c0c fe30 cef0 0ef0 fe30 fef0  .0>....0.....0..
00000a40: fcc0 fe30 fef0 fe0e 0ef0 fc30 fef0 fec0  ...0.......0....
00000a50: 3ece 0ef0 fe80 8cf0 3efe fe3e 0ece ce0e  >.......>..>....
00000a60: 8cf0 ce3e cefe 30fe 0efe 303c f0fe 30ce  ...>..0...0<..0.
00000a70: f00e f0fe 30ce f08c 0efe 300e f03e f0fe  ....0.....0..>..
00000a80: 30fc f0ce 0e0e f0fe 303e f0ce f0fc 30ce  0.......0>....0.
00000a90: f0fe c0fe 303e f0fe 80fc 30ce f00e f03e  ....0>....0....>
00000aa0: f0fe 300c f03e f0fe 303e f00e f0fe 303c  ..0..>..0>....0<
00000ab0: f0ce c0fe 300e f0ce 0efc f0fe 303e f0fe  ....0.......0>..
00000ac0: c0fe 303e f0fc 0cfe 30fe 0ece c0fe 30ce  ..0>....0.....0.
00000ad0: f08c f0fe f0fe 300e f03e f03c 8c0e f00e  ......0..>.<....
00000ae0: f0ce f03e fefe 3e0c cece 0ece f0ce 3ece  ...>..>.......>.
00000af0: fe30 fc0e fe30 0ef0 fe30 cef0 0cf0 fe30  .0...0...0.....0
00000b00: 3ef0 0ef0 fe30 3ef0 fcf0 fe30 3ef0 cec0  >....0>....0>...
00000b10: fec0 fc30 3ef0 0ef0 fe30 0ef0 3ef0 fc30  ...0>....0..>..0
00000b20: 3ef0 3ef0 fe30 3ef0 0ef0 3cf0 fe30 3ef0  >.>..0>...<..0>.
00000b30: ce0e fe30 fc0c 3ef0 fe30 3ef0 ce0e fe30  ...0..>..0>....0
00000b40: 3cf0 0ef0 fec0 fe30 0ef0 fef0 fc30 fe0e  <......0.....0..
00000b50: fec0 fe30 3ef0 fc80 fe30 3ef0 0ef0 fe0e  ...0>....0>.....
00000b60: fe30 0cf0 fef0 3ece 0ef0 0ef0 8cf0 3efe  .0....>.......>.
00000b70: fe3e 0ece ce0e 8cf0 ce3e cefe 30fe 0efe  .>.......>..0...
00000b80: 30fe 0cfc 30ce f00e f0fe 30ce 0e8c f0fe  0...0.....0.....
00000b90: 300e f0ce c0fe 303e f08c f0fe 0efe 300e  0.....0>......0.
00000ba0: f03e f03e 8cfc 0e0e f0ce f03e fefe 3e0c  .>.>.......>..>.
00000bb0: cece 0ece f0ce f0ce 300c f0ce c0ce f0ce  ........0.......
00000bc0: 0e3e 3e3c ce0e 0ef0 fec0 fef0 fe30 3cce  .>><.........0<.
00000bd0: 30fe f0fe c0fe 0ece f0fc c03e 3e3e 3ef0  0..........>>>>.
00000be0: 0ef0 8c0c 0ef0 fe30 0ece fe30 3ef0 fcf0  .......0...0>...
00000bf0: fef0 0ef0 fef0 cef0 3e3c f0fe f0fe 30ce  ........><....0.
00000c00: ce30 fcfc cece 3ec0 f00e f0ce f03e fc00  .0....>......>..
00000c10: 3c0c cece 3ece cef0 cef0 ce30 3ef0 fef0  <...>......0>...
00000c20: fef0 0ef0 fef0 3cf0 3e3e f0fe f0fe 30ce  ......<.>>....0.
00000c30: 8c30 0ef0 cec0 cef0 ce0e 3c3e 3ece 0e0e  .0........<>>...
00000c40: f00e f03e f0fc 303e ce30 fef0 fec0 fc0c  ...>..0>.0......
00000c50: cef0 fec0 3e3e 3e3e f00c f0ce 0efe c0fe  ....>>>>........
00000c60: 300e cefe 30fc f03e 3ef0 ce0e cef0 fc30  0...0..>>......0
00000c70: fe30 fef0 ce0e fef0 ce80 3cf0 cef0 fe30  .0........<....0
00000c80: fe30 fe30 fefc 8cce 3e30 fef0 cef0 3efe  .0.0....>0....>.
00000c90: fc3c 0ece ce3e cefe cece c08c 30fe 30fe  .<...>......0.0.
00000ca0: cece 30fe 308c f0cc 30fe f03e 3ef0 ce0e  ..0.0...0..>>...
00000cb0: 8cf0 fe30 3ece 30fe f03e 3cf0 cec0 fe0e  ...0>.0..><.....
00000cc0: fe30 0e3e fc30 fefe cece 3e3e 3ece 0e3c  .0.>.0....>>>..<
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[MIS42N]

I get a stream of binary nonsense every second, about 5120 bytes per transfer, at 9600 baud.

There is something wrong here. The rule of thumb is 1 character for every 10 baud (1 start bit, 8 data bits, 1 stop bit). So should only get a maximum of 960 characters/second. Maybe the receiver has the ability to detect the baud rate and is locking onto the wrong rate.

Are you setting the receiver right. 1 start bit, 8 data bits, 1 stop bit, no control signals usually works.

There is a difference between RS232 and TTL. RS232 a 1 is -ve and a 0 is +ve. TTL a 1 is +ve and a 0 is 0. So the levels are opposite and are not interchangeable. Also a true RS232 receiver should not recognise a 0V signal, to have an active idle line there should be a 0 logic level, i.e. greater than +3V.

I have used the TTL to USB converters. They do require the right driver, make sure it works before attaching it to a circuit. You can do that by connecting the TX and RX lines and use a terminal program like PuTTY. If typed characters are echoed back it is working OK. I have had dodgy connectors provided with some converters.

The RPi receiver looks to be running at a much higher rate than the data. I am basing that on the hex received. The majority have adjacent 1s and adjacent 0s. 3c=00111100 ce=11001110 etc. But that's a guess.

[burkm]

Just some feedback from my "incarnation" of the latest BG7TBL GNSSDO (no front date), which has been delivered "brand new" on August 5th 2021, PCB version 2021-06-10, software version "20191001". After > 30 days of uninterrupted run-time (possible OCXO retrace, but  "stable" for the last 14 days) it has a documented deviation (Fluke high resolution counter PM6685 + external 10MHz star 4+ ATDC reference) of ~ -0.0244Hz which is a rather "large" compared to the promised max. deviation of 0.0002Hz (2E-11). Even the built-in LCD-display shows a similar value below 10 MHz !
A roof top mounted - active - timing antenna + GPS splitter delivers the GPS/GNSS signal of the supported satellite networks. The installed GPS chip is unlabeled (?) and supposed to be an Ublox Neo-8M (seller satement), which I didn't check yet. Antenna voltage had already been set to 5VDC by BG7TBL.

The built-in (OEM-)OCXO 48S1164 is (probably) made by C-MAC (now Rakon), date code December 2012, of rather "unusual" size (50.8x50.8x24mm) and pin out, wich seems to be "similar" to a Trimble OCXO etc. I couldn't find any specific information for it on the internet and it - unfortunatelly - can't be replaced easily (i.e Oscilloquartz 8663-XS, standardized), because of the form factor and pin out. Additionally the PCB itself is only populated (componentwise) for this built-in OCXO. The tuning voltage amplification factor had already been set (solder bridge) by BG7TBL to "x3". As measured, the OCXO could actually reach 10 MHz at 5.245 VDC but the supplied hardware and/or software algorithm won't let it (see above) for unknown reasons, staying always below this value, which is responsible for the given deviation.

After some lengthy conversation over the last 30 days (and raising a "conflict" through PayPal) the seller promised now to sent a "new unit", which is supposed to be working as stated by the "official" specs.

I will keep you up-to-date, after it arrives...

[AndrewBCN]

Nearly two months ago, 

@burkm
...
I think worrying about real or fake u-blox GPS modules in a BG7TBL GPSDO bought on eBay, Amazon or AliExpress is somewhat missing the point: these are very cheap instruments that either work within specifications and satisfy your needs, or you should just return them to the seller and buy professional grade (and certainly more expen$ive) instruments.

Now:

...
After some lengthy conversation over the last 30 days (and raising a "conflict" through PayPal) the seller promised now to sent a "new unit", which is supposed to be working as stated by the "official" specs.

I will keep you up-to-date, after it arrives...

So you roll the dice again and the saga continues... 

[burkm]

The seller decided to sent a new unit several days ago because of the stated problems. Hopefully I get more lucky this time. Tracking ID has been provided...
I don't know, what will happen with the import tax and customs fees etc. because he did sent it "free of charge". Will see, what the customs office will do about it...
Note: I wasn't sure, where my conflict (PayPal) will take me, because this would take some time for a response of the seller, contacting Ebay and a final decision abou a full or partial refund. Ebay refuses to tackle it as usual, after I checked with their help line, because of separation from PayPal.
Sending back "defective" unit to China from over here is relatively expensive because of high logistics costs, getting back the already charged/paid import taxes and fees from the customs department is truly laborious over here.
This would have to be deducted anyways from the price already paid to the seller too.

[burkm]

The replacement unit seems to have reached the German customs a few days ago. I'm waiting for the delivery now...
I'm eager to know, how the German customs will handle the replacement, because the replacement unit has not been charged by the seller. An invoice and customs statement of the seller should list 0,0 cost.
Another question will be, how the replacement unit will handle the task and if it will hold the stated specs.

[burkm]

After looking up the tracking info of the package, I discovered, that the provided tracking-ID of the replacement unit seems to point somewhere else but not my address, because the tracking info shows a different city now. I called DHL Germany about the whereabouts of my package, whose tracking-ID had been provided by the seller flyxy2015 on ebay. The lady from the DHL customer service told me (to my surprise), that the tracking ID belongs to a completely different customer in a different city in Germany. Seems that the seller flyxy2015 had probably provided an existent but "fake" tracking ID based on my previous complains, knowing, that China is far away...

I contacted the seller flyxy2015 by the ebay messaging system today again and asked about the "real" tracking ID of my package, but after looking casually around on the internet, it seems, that the seller flyxy2015 has been known already before as a cheater on those things like the tracking ID in case of complaints. Thus it would surprise me, if I would get any answer from the seller. Unfortunately the 60 days period has passed already on ebay, so I can't leave any negative comments about this behavior. Probably the actual intent of the seller...
So I suggest, that anyone, who reads this, is staying away from this seller.
If any further news will show up, I will post here.

Fortunately PayPal seems to be of some help in this situation, so not everything is lost 

[burkm]

I got a response from flyxy2015, that he will contact the post office to look for the sent package and would sent another one
Strangly enough, because the German post (DHL) had told me already, that the provided tracking-ID did belong to a different person. Notwithstanding this response flyxy2015 told me, that he would to resend the package "soon". In the meantime I contacted ebay about this scam. If this will help, I don't know.

[burkm]

Just got a new tracking-ID from flyxy2015, which is supposed to be for my address. Checking its destination, its been sent - again - to a completely different address: city and postal code over here.
Today I also got a letter from DHL Germany, which responded - in writing - to my original search request and told me, that the sent package in question had been redirected to the local post office (different adressee, different city and different location all together), because nobody was present at the original delivery address. Within the provided holding period the package has been picked up by the recipient, adifferent person. This was certainly not me, because the destination address provided by the sender was located elsewhere in Germany and does not correspond to my home address.
Strange things seem to happen...
 
My belief: flyxy2015 is trying to cheat on me, again. Thus beware ! 
I think this story is over now as been told...

PS.: Interesting. flyxy2015 has changed (at least partly) its current name for Ebay offers (Germany ?) to => elecdesign2015
if anything "new" comes up, I will post here...

[burkm]

I confronted the seller with the findings through the ebay messaging system, that his provided "new" tracking-ID for me was sent (again) to a completely different address (and probably addressee), but he did not respond / react at all, just complete "silence"...

PS.: In the meantime the 2nd package / item has been delivered and (again) signed by the "real" addressee (different city, different address, different person), so its evident, that any warranty is non-existent, a replacement unit will never reach you, even if "promised" by the seller flyxy2015 / elecdesign2015
Note: Unfortunately the ebay comment period has expired in the (long) meantime, which seems to be the whole purpose behind these actions as reported by others too. Thus his "positive rating" stays untouched by those unpleseant experiences.
I contacted ebay Germany about this, but earned only shrugs about this. Earned money seems to count more for them...

[burkm]

Just had a casual look at my "new" (3 month old) BG7TBL GNSSDO + Display unit. After 3 Month of beeing connected continously to the power supply and GPS antenna, the built in LCD-Display shows a value (2nd line) of "9 10 MHz -0.0243 Hz", far off the stated specs. The "9" does seem to show, that it is off spec, but my other BG7TBL GPSDO unit just works (almost ?) perfectly (12-digit + overflow Fluke PM6685 counter). The oscilloscope shows a right shifting signal compared to the star 4+ version I got. Both are connected actively to a single GPS timing antenna on top of the roof with almost free "hemispheric" sight of the sky by a GPS splitter.

[KD0CAC John]

Lot's of sources , looked getting a while back , looking at getting again - but same issue - too many sources .
Did lots of searches [ must be bad at searching ] so asking where / who to buy from ?
Thanks

[aronake]

I been reading though lots of threads on GPSDO, but still not figured out which to buy. Which of the versions of bg7tbl are most recommended and why?

[rfspezi]

Same here... wondering which version (with display) is a good choice.
Mainly need it as reference for occational recalibration of my measurement equipment.

[bborisov567]

It may seem like a stupid question but where can i find a full list of all terminal commands? Typing “help” doesn’t work. Also i ordered a proper gps antenna but what is the best diy antenna that i can use until i get the real one?

[MIS42N]

Also i ordered a proper gps antenna but what is the best diy antenna that i can use until i get the real one?

I have just done an evaluation of a cheap active GPS antenna ($4AU) with a NEO-6 GPS module, the results were clear that the antenna is not critical, but where it is positioned is very important. In my opinion if there is enough signal strength to work, but the antenna position is poor, then upgrading the GPS module to a timing module will be more effective than getting a better antenna. I've attached my evaluation.

[metrologist]

Also i ordered a proper gps antenna but what is the best diy antenna that i can use until i get the real one?

I think the quadrifilar helix is a great DIY antenna.

https://www.eevblog.com/forum/beginners/suitable-gps-for-gpsdo-ocxo/msg1260063/#msg1260063

[Bushougoma]

I was able to purchase a BG7TBL on Amazon and wanted to post pics of the internals here. It seems that this original design has matured to the point where the only real difference we're going to see is different OCXOs and possibly GPS modules.

The date on the board is 6-10-2021. Mine came equipped with a CTS Model 196 square wave output OCXO and uses an (unlabeled) Ublox NEO M8 GPS module. Well that's what Ublox U Center identified it as anyway.

The 1PPS signal is triggered on the rising edge and the 10 MHz sine wave is clean as far as I can see.

It is a NMEA receiver and Lady Heather has no issues communicating with it a straight through serial cable is all that's needed.

It draws a steady 400 mAh @ 12 volts as the OCXO warms up which drops to a steady 220 mAh afterward.

[Bushougoma]

The GPS receiver is pretty sensitive and I was able to achieve a steady GPS lock with the included puck antenna in the center of my basement lab. With the puck antenna in a basement window facing North (worst direction I know) with a partial view of the sky the SNR from LH over 24 hours was pretty bad. The majority of which was <20 SNR.

I quickly upgraded to an external antenna and from a bang for buck perspective ($35.00) I was very impressed with this Abracon AEACMK0660746-SG4 I purchased off Digikey.

Adapting it to a pole mount (since it mounts via a stud) took some doing but I was able to make it work (was able to find all of the hardware on Amazon). Mounted it about halfway up my roof. Used 25 feet of RG-58 as feed line with the antennas high LNA gain of 40 dB I wasn't too worried about loss over such a short run.

I'm pleased with the end result I consistently have a good signal from 10 satellites at all times.

[usagi]

Looks like there is a new GPSDO, with supposedly rubidium disciplined oscillator. "GNSS-RB" on ebay.