| homebrew INTERSIL | handmade 7216B | 1? | 0-150MHz | not tested, but I can tell it is not good | xtal, TCXO | yes | none, ICM datasheet | wall wart | internal NiCd | 2024-01-02 | $20 | Anchor Electronics door special | BNC | low senitivity, internal noise | 3" square cast Al box, dead-bug+socket, 2x5082-7415 display |
| ?? | E0330 | ?? | 0-50MHz | not tested | yes | online | wall wart | N/A | 2015-04-?? | $15 | ebay, china | ZIF | flakey | 5-digit counter for xtals | |
| Agilent | 53131A | ?? | 0-225MHz | 225@-18 301@0 | yes | online | IEC | N/A | 2016-10-19 | $245, $30 handle+bumpers | ebay | BNCs, GPIB, RS-232 | on cart | totalize, 12 dig(10/s), GPIB, serial | |
| Extech | 380282 | ?? | 0-1MHz | 1.5@0 | yes | pamphlet | N/A | 9V | 2016-05-14 | $60 | De Anza | banana, serial | daily DMM | DMM w/1MHz counter, square-wave source | |
| HeathKit | IB-1103 | ?? | 0-180MHz | not tested | TCXO 999999.98169 Hz Mean, on extender | recovering | online | weird | N/A | 2017-04-07 | $55 | TESLA (!) | BNC | ext ref, needs repair on input board | Nixies! TCXO! |
| HP | 5315B | 2538A03741 | 0-100MHz | 170@-20 170@0 | TCXO 9999999.923671428 Hz mean | yes | online | IEC | N/A | 2015-04-?? | $30 | De Anza | BNCs | on shelf | ext ref switch inside. custom TCXO |
| HP | 5316B | 2708A00981 | 0-100MHz | 101@-20 171@0 | XO 9999999.923966667 Hz mean. Varies 20/mHz in a few minutes. could fit TCXO I made for 5315B | yes | online | IEC | N/A | 2019-04-13 | $50 | flea @ Fry's | BNCs, GPIB, testpoints | Tweaked stock XO, not option 001. | difficult GPIB. same depth as 16A? Bail feet |
| Racal | 9915 | ?? | 0-520MHz | 60/520 60@-40 75@0 78@10 520@-28 720@0 | OCXO 1000000.0000861111 Hz mean tweaked. Gains 20mHz/day, smallest tweak gets that. hysteresis. Much better with 1MHz ublox as ref on 53131A vs Tbolt | was wired for 240V | not yet | IEC | internal, deadish | 2017-05-13 | $2 | De Anza | BNCs, testpoint | rewired for 125V. many screws frozen. still needs cosmetic reconstruction. | live count in burst mode, has prescaler _and_ multiplier, and OCXO, and AGC out? |
| Sabtronics | 8100 | ?? | 0-100MHz | 100@-17 147@0 160@13 | Sweet spot appears to be 3.5795400MHz. That's embossed on the xtal. Probe capacitance accounts for 500mHz. drifts anyway | wasn't | online | wall wart | holders not connected | 2017-08-12 | $5 | De Anza | BNCs | replaced 75492, 2x FND357 | almost colorburst reference frequency |
| Systron-Donner | 6150 | ?? | 0-50MHz | 67MHz, 71@5 | yes | not yet | IEC | N/A | 2017-05-13 | $60 | De Anza | BNCs, combs | Nixies! 8- and 9-digit optional. 2U rack mount. crystal? | one of those counters that live-counts for a while, stops to display, then starts over | |
| Tektronix | CDC250 | ?? | 0-175MHz | 212@0, 213@3 | TCXO | yes | online | IEC | N/A | 2014? | $125? | HSC | BNCs | loose BNC brought price down a little | TCXO, totalize, ext ref |
| Tektronix | CFG280 | ?? | 0-11MHz | 89@-20 131@0 132@15 | 1MHz de GPSDO showed 1.000002 MHz. | yes | online | IEC | N/A | 2014? | $110? | ebay | BNCs | can get about 7D resolution from 5D counter | swept function generator, modulation inputs |
| Tektronix | CMC250 | ?? | 0-100MHz,80M-1.36GHz | 1MHz GPSDO reads 999.9975 at 10 sec; 990.0000MHz reads 989.99700 at 27 sec | TCXO? | yes | online | IEC | N/A | 2024-08-11 | $25 | West Valley Flea | BNCs | timebase tweaked to 1ULP at 10s low range, about 27ULP 30s high range | no TCXO, totalize, no ref |
| Tektronix | 2715 | ?? | 0.009-1800MHz | not tested | mostly | online | IEC | N/A | 2016-05-13 | $260 | ebay | 75R F, RS-232 | on cart | 1Hz counter for tuned signal is broken | |
| Tektronix | DMM916 | ?? | 0-4MHz | not tested | counter works | yes | N/A | 9V | 1990? | $300? | Fry's | banana | shelved | Flakey DMM w/4MHz counter | |
| Fluke | 1900A | ?? | 0.000005-80MHz | 108@0 | yes | online | IEC | N/A | 2018-04-06 | $20 | C&H, Duarte | BNC | Disposed at flea mkt 2018-09-08 | GIFT OF/JOHN FLUKE/MAY 1986 | |
| HP | 5316A | ?? | 0-100MHz | 100@-12 190@0 192@6 | yes | online | IEC | N/A | 2015-10-?? | $40 | ebay | BNCs, GPIB, testpoints | Sold flea market 2019-08-10 | difficult GPIB, extref switch outside. |
[1] Report as ppm? 10^-x? Actual standard measured?
Method? Measure internal reference against GPSDO? Measure GPSDO using internal osc?
Get rubidium involved?