Re: [time-nuts] HP E1938

Mention of the E1938 reminded me that I have a schematic that measures 36" X 72" (yes, 3 feet by 6 feet) !! Talk about readability. Also, somewhere, I still have one of them. I'll need to go find it and try firing it up. Now you got me going again ... 73, Dick, W1KSZ Sent from

Re: [time-nuts] uncertainty calculations

t...@radio.sent.com said: > * You might have any possible phase relationship between the two > signals. If they are exactly related by a 10^7 ratio, it's possible > for the 1 PPS edges to exactly coincide with the 10 MHz edges. > Depending on the type of gating circuit, you will have jitter

Re: [time-nuts] HP-59309A Clock counts only seconds

Update: The 4011s arrived in good condition. The sockets arrived today (I ordered a whole bunch with various numbers of machined pins as Tom Miller recommended). All the sockets were of the "good" kind except for the 14-pin sockets, which were the cheap kind in accord with Murphy's Law. :-(

Re: [time-nuts] HP E1938

More precisely the active EFC range is +1.25 to +3.75V with an absolute minimum of 0V and an absolute max of +5V. At least this is the range that the pseudo differential AD7714 ADC inputs monitoring the EFC are configured for. Bruce > On 16 April 2017 at 14:57 Bruce Griffiths

Re: [time-nuts] HP E1938

0 to +5V dc max, however only the 0 to 2.5V range appears measurable by the AD7714 ADC on the PCB. Increasing the EFC voltage decreases the capacitance in series with the crystal requiring an increase in the inductance exhibited by the crystal hence requiring a lower oscillator frequency.

Re: [time-nuts] uncertainty calculations

I believe that the problem is that the error in any one measurement is not uniformly distributed in exactly that way. If you are trying to count how many 10 MHz (100 ns interval) intervals occur between the 1 PPS edges in a period counter, you have to deal with the following? * You might have

Re: [time-nuts] HP E1938

The units now available on eBay have various types of D-Subminiature connectors and can be on either side of the board. I will have to wait until my unit arrives to see what I get. It should be possible, if necessary, to remove the connector and replace it with a more convenient D-Submin

[time-nuts] E1938A

Hello Tom, There are two versions of the E1938A, one has a male DB-25 and one has a female DB-25 (mounted on the opposite side of the board as the male). Pinout and functions are the same between the two versions. If your hardware is expecting one type but all you have is the other an adapter

Re: [time-nuts] HP E1938

It's been 20 years, but I will try to recap what I remember about this connector. I believe there were 3 customers, and one of them required the DB connector with coax inserts for reasons of backward compatibility. I think this vendor was Motorola. We did not actually use the coax inserts, but

[time-nuts] Motorola T5829A Specifications

Does anyone know the aging and temperature specifications of a Motorola T5829A "Ultra High Stability Oscillator"? This is a 5 MHz standard containing an OCXO. After a day of operation, the next 24 hour drift was 2.5E-9 lower, but change due to temperature variations is unknown. A nearby HP-105B

Re: [time-nuts] HP E1938

Re: schematic. There's a link on the second ebay auction page: http://www.prc68.com/I/pdf/E1938pdfdocs.zip On Sat, Apr 15, 2017 at 10:42 AM, Larry McDavid wrote: > Ok, so a standard DB 25-pin socket-contact connector will mate with the > on-board connector with the center

Re: [time-nuts] HP E1938

Ok, so a standard DB 25-pin socket-contact connector will mate with the on-board connector with the center hole and missing pins. That's good! I now notice a comment on your webpages about this device in which you mention a schematic. Do you have a schematic of this board? If so, can you

[time-nuts] datasheet info on Vectron VCXO

Hi, I have a 500Mhz VCXO that I picked up a hamfest for free, but have had a devil of a time finding anything at all about it. I've checked google, ebay, and this list archive but can't find anything at all. I'd like to use it for a GPSDO, frequency counter, or similar project in the future. The

Re: [time-nuts] NTGS50AA No Serial

I had a stupid problem with mine when doing some tests and I had the same symptoms and it took me several days of tests to realize the problem. The original flat cable that goes to the auxiliary board with the panel lights and the RS-232 connector has the pins reversed so if you connect the

Re: [time-nuts] NTGS50AA No Serial

I had a stupid problem with mine when doing some tests and I had the same symptoms and it took me several days of tests to realize the problem. The original flat cable that goes to the auxiliary board with the panel lights and the RS-232 connector has the pins reversed so if you connect the

[time-nuts] Measuring coax temperature coefficient with a TICC

I finally got around to using a TICC to measure the temperature coefficient of 100 feet of generic RG-58 coax using a TICC. The TICC was clocked by a HP 5071A 10 MHz output. The 1PPS output was connected to the input of the coax and the TICC chB input. The TICC chA input was connected to

Re: [time-nuts] HP E1938

Tom #1 proved useful when this sub assembly failed (no 10MHz output) in my E1938A. Someday I'll disassemble it to see what exactly failed. Also have #3 which works well when one figures out the connections on the PCB and the unusual backplane connector. Bruce > > On 16 April 2017 at

Re: [time-nuts] NTGS50AA No Serial

Have you tried different serial settings I wonder if the hard reset mucked things up. have a Nortel as well, never had a issue with a reset but try changing a few thing sup. It may need the unusual 19200,7,Odd and 1 stop bit setting. If you try a terminal program do you at least see some

Re: [time-nuts] HP E1938

> I purchased one of these HP E1938 OCXO recently on eBay but have not yet > received it. > > Is that special D-Submin connector a receptacle-shell, pin contact > version? Will a standard plug-shell, socket contact 25-pin D-Submin fit it? Hi, I'll cc the group here since we may get some

[time-nuts] NTGS50AA No Serial

My NTGS50AA is suddenly lacking the ability to communicate. It's been working fine for months, but I was trying a few things with my Raspberry Pi NTP server. Had GPSD accessing the NTGS50AA through a ch340 USB to serial adapter. Found out Lady Heather displays much less info when connecting