| Agilent | 1588-LXI | MY43002681 | PTP, xtal | 25Mhz RXTXclk | apparently | no | IEC | N/A | 2018-02-?? | $20 | WeirdStuff | BNCs, serial, USB, 100BT=thing1 | 25MHz TXCLK-RXCLK~1000Hz | PTP demo | |
| Agilent | 1588-LXI | US42000101 | PTP, xtal | 25Mhz RXTXclk | apparently | no | IEC | N/A | 2018-02-?? | $20 | WeirdStuff | BNCs, serial, 100BT=thing2 (no USB opening) | 25MHz TXCLK-RXCLK~1000Hz | PTP demo, TS works | |
| Chronetics | PG-11 | 158 | R/L/C | 0-20MHz | partially | ? | wired | N/A | 2019-04-13 | $10 | flea @ Fry's | BNCs | sync works, final amp doesn't--may bypass | pulse generator | |
| Extech | 380282 | xtal | 0.5, 1, 2, 5, 10, 50, 60, 75, 100, 150, 200, 300, 600, 1000, 1200, 1600, 2400, 4800 Hz | 4800.046235680001 Hz mean | yes | pamphlet | N/A | 9V | 2016-05-14 | $60 | De Anza | banana, serial | daily driver | DMM w/square-wave source | |
| FEI | 5680A | 0527-96364 | Rb | 1Hz, 10MHz | 9999999.989175 Hz mean cold 10000000.000592856 Hz mean warm |
yes | online | adhoc, breakout board | N/A | 2016-10-07 | $107 | Time Nut | SMA, serial | A man with two watches is never sure | Rubidium standard |
| Heathkit | IG-4505 | xtal | 1, 2, 5 x 10^0..6 Hz | 1000004.7931780001 Hz mean .1uS | yes | online | wired | N/A | 2015? | $50 | ebay | BNC, banana | enclosed | scope calibrator. Removed 50R lump | |
| Heathkit | IOA-4510-1 | xtal | 1kHz, 10kHz, 100kHz, 1MHz | 1000008.0493371428 Hz mean | yes | online | N/A | 5VDC wires | 1978? | $30+? | came w/Heathkit blue scope I later sold | testpoints | bare board | scope calibrator | |
| Heathkit | GC-1000 | WWV | 3.6MHz (not color burst) | 3599987.56775 Hz mean | yes | yes? | wired | external 12V for moving | 1983? | $300+? | Heathkit, Hopkins | BNC, serial | noise swamped | WWVDO | |
| Heathkit | GC-1000H | WWV | 3.6MHz (not color burst) | 3599981.321911765 Hz mean, unset | repaired | yes? | wired | external 12V for moving | 2018-04-06 | $call | C&H, Duarte | BNC | recently aligned | WWVDO | |
| HP | 8656A | 2208A02828 | OCXO? or ext ref | 0.100 thru 990MHz | 9999997.575258823 Hz mean OCXO | wasn't | online | IEC | N/A | 2018-01-?? | $75 as-is | HSC | N/BNC, GPIB | replaced fuse | signal generator, GPIB |
| RaspberryPi | B | NTP, xtal | 40kHz-250MHz | yes | online | USB charger | N/A | 2013-12-xx? | gift | MJB | breakout, HDMI/RCA, USB, 100BT=rpi | interpolated | frequency generator | ||
| Tektronix | 2235 | B022915 | R/L/C | 995Hz | yes | yes | IEC | no | 2018-03-10 | $40 | De Anza | BNC, testpoint | basic analog | use calibrator | |
| Tektronix | 2236 | R/L/C | ~995Hz | yes | yes | IEC | no | 2024-04-14 | $20 | West Valley | BNC, testpoint | basic analog, w/CTM | needs minor maintenance: fan, range switch for CTM | ||
| Tektronix | 455 | B057713 | R/L/C | 943Hz | yes | yes | wired | no | 1987 | $80? | Foothill flea market | BNC, testpoint | repaired | use calibrator | |
| Tektronix | 455 | R/L/C | ~943Hz | no | yes | wired | no | 2023-07-31 | $20 | West Valley flea market | BNC, testpoint | donated magic smoke to other 455 | |||
| Tektronix | 2440 | B012584 | xtal | 50Hz, 500Hz, 5kHz, 50kHz, 500kHz, 1MHz, 5MHz | yes | online | IEC | N/A | May 2015 | $125 | ebay | BNC, testpoint, GPIB | workhorse | use calibrator | |
| Tektronix | CFG-280 | TW11597 | xtal for counter | 0-11MHz | yes | online | IEC | N/A | 2014? | $110? | ebay | BNC | can get about 7D resolution from 5D counter | swept function generator, modulation inputs | |
| Tektronix | QuickStart8 | xtal? | various | yes | yes | 9VDC wall wart | USB | 2015? | $70? | ebay | SMA, testpoints | 200ps fast rise | scope demo board | ||
| Tektronix | TSG-170A | OCXO | 3.5795454545... MHz | 3579544.4572949996 Hz mean cold 3579544.7681599995 Hz mean |
yes | online | IEC | N/A | 2018-12-27 | $25 | APEX | BNC | OCXO drifts across spec | ||
| Trimble | Thunderbolt | GPS | 1Hz, 10MHz | yes | online | brick | N/A | 2014-04-21 | $202 | Leapsecond | BNCs, serial | has 1024-week rollover problem; Lady Heather compensates | GPSDO | ||
| test_tool | generic | GPS: LEA-M8F | 1Hz thru 24MHz; 30.72MHz REF | yes | online | USB | N/A | 2020-06-03 | $80 | ebay | USB, SMA | ||||
| ublox | EVK-G20 | GPS: LEA-6H | 1Hz thru 24MHz; 48MHz int divs best | yes | online | brick | button for GPS | 2019-05-11 | $5 | Fry's flea | USB, serial, CDMA | killed TIMEPULSE output trying to tack a wire on pullup resistor :-( | see deviation spreadsheet | ||
| ublox | LEA M8F | GPS: LEA-M8F | 1Hz thru 24MHz; 48MHz int divs best | yes | online | USB | button for GPS | 2020-06-03 | $80 | ebay | USB, SMA, CDMA | Needs to be nailed down. | someday, deviation spreadsheet | ||
| voltagestandard.com | DMMCheckPlus | 3003 | xtal | 600Hz, 5kHz | 599.9042667044446 Hz mean 5000.202958626667 Hz mean |
yes | online | N/A | 9V | 2013? | $85? | voltagestandard.com | testpoints | overdue for recal | DMM checker; freq less strict |
| HP | 3311A | R/L/C | 0-1.6MHz? | yes | online | IEC | N/A | 2013? | $100? | HSC | banana | Disposed at flea market 2018-09-08 | Fairly basic function generator | ||
| Tektronix | 2440 | B015127 | xtal | 50Hz, 500Hz, 5kHz, 50kHz, 500kHz, 1MHz, 5MHz | yes | online | IEC | N/A | 2015-05-09 | $100 | ebay | BNC, testpoint, GPIB | disposed at flea market mid-late 2019 | use calibrator |