Re: [time-nuts] E1938 oven design

Hi I certainly saw the “positive gain at this setting” going to “negative gain at that setting” result on a lot of OCXO designs. I never had the patience (or a stable enough system) to get into the millions or even 100K’s on a single oven. As a practical result, a gain of -500 is not really

Re: [time-nuts] E1938 oven design

On 6/11/2017 8:59 AM, Attila Kinali wrote: The exact insulation is relatively unimportant. We even tried still air using a knife edge cradle. Didn't make much difference. What is a knife edge cradle? We wanted to test still air as insulation. We couldn't just replace the insulation

Re: [time-nuts] E1938 oven design

On Thu, 8 Jun 2017 16:17:20 -0700 "Richard (Rick) Karlquist" wrote: > We were stuck under 1,000 for a long time > using only face heaters. I still remember the > day that I rigged up the first crude rim header > by winding a piece of magnet wire around the rim > and

Re: [time-nuts] E1938 oven design

Yes, that's right. The copper oven mass has two pieces: a main piece and a lid. The main piece has a wall around the outside into which the cover fits, using an O-ring. In the center, there is a cylindrical cavity into which the crystal mounts. It is like a 10811 crystal, except the height is

[time-nuts] E1938 oven design (was: Poor man's oven)

On Wed, 7 Jun 2017 14:21:52 -0700 "Richard (Rick) Karlquist" wrote: > The crystal case is well connected to the oven mass and gets > heated by conduction. I don't think radiation is a player. Do I interpret the papers correctly, that the oven mass is a closed can, with

Re: [time-nuts] E1938 info regarding LEDs, push button switch and EFC voltage notation

You can find schematics and various info here: On Thu, May 11, 2017 at 3:47 PM, James Robbins wrote: > 1. I have just acquired an E1938 and

[time-nuts] E1938 info regarding LEDs, push button switch and EFC voltage notation

1. I have just acquired an E1938 and powered it up. It seems to work. I see that it has 4 blinking board LEDs (green, red, yellow, yellow) and a pushbutton switch at the end of the board opposite to the DB25 connector. Can anyone point me to either the schematic for the board or what these

Re: [time-nuts] E1938 PIC hex files?

Hi Dan, If the 1938 was purchased through Fluke1 he is usually very good about replacing bad items he sells to Time-Nuts. You might want to contact him about a replacement unit or perhaps getting a pre-programmed PIC from a different unit to try. Richard I am beginning to think that the PIC

Re: [time-nuts] E1938 PIC hex files?

McCorkle mccor...@ptialaska.net Subject: Re: [time-nuts] E1938 PIC hex files? To: dan...@verizon.net, Discussion of precise time and frequency measurement time-nuts@febo.com Date: Saturday, 13 June, 2009, 7:16 AM Hi Dan, If the 1938 was purchased through Fluke1 he is usually very good about

[time-nuts] E1938 PIC hex files?

I am beginning to think that the PIC in my Chinese Ebay 1938 is dead or at least injured. Does anyone have the hex files for this one? Blank PIC16C74As can be had and it may be worth my trying to program a new one. Nothing else seems to make it work and as the PIC seems to be asleep, I'm

[time-nuts] E1938 question

I have one of the Chinese E1938 modules I bought about a month ago. I just tried it out on the bench, and have not had much luck with it. The 5 Volt supply never goes above 50 mA or so, none of the heaters seem to be powered looking at the hockey puck D-sub connector pins. The four leds up

Re: [time-nuts] E1938 question

Dan Rae wrote: I have one of the Chinese E1938 modules I bought about a month ago. I just tried it out on the bench, and have not had much luck with it. The 5 Volt supply never goes above 50 mA or so, none of the heaters seem to be powered looking at the hockey puck D-sub connector pins.

Re: [time-nuts] E1938 question

Dan Rae wrote: I have one of the Chinese E1938 modules I bought about a month ago. I just tried it out on the bench, and have not had much luck with it. The 5 Volt supply never goes above 50 mA or so, none of the heaters seem to be powered looking at the hockey puck D-sub connector pins.

Re: [time-nuts] E1938 question

Dan Rae wrote: I have one of the Chinese E1938 modules I bought about a month ago. I just tried it out on the bench, and have not had much luck with it. The 5 Volt supply never goes above 50 mA or so, none of the heaters seem to be powered looking at the hockey puck D-sub connector pins.

Re: [time-nuts] E1938 question

Dan Rae wrote: I have one of the Chinese E1938 modules I bought about a month ago. I just tried it out on the bench, and have not had much luck with it. The 5 Volt supply never goes above 50 mA or so, none of the heaters seem to be powered looking at the hockey puck D-sub connector pins.

[time-nuts] E1938

); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY Dear All, After some shipping time, my E1938 arrived today! :-) :-) :-) Thank you Rick! First thing was examining the board, oscillator and the HP-test notes/labels. Most of the specs mentioned there are logical and

Re: [time-nuts] E1938

The labels may or may not be significant. If the frequency is indeed -2.94 Hz at 2.5V EFC, you could probably get it back to 10 MHz by increasing the EFC voltage. You can also decrease the bridge capacitor to bring the frequency up if necessary. The factory was supposed to choose the capacitor

Re: [time-nuts] E1938

); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY Hi Rick: If the aging drift is up in frequency then there might be an advantage in starting at the low end of the window. Any idea of how these age? Have Fun, Brooke Clarke http://www.PRC68.com

Re: [time-nuts] E1938

Hi Rick: I've heard that but it's not clear to me which oscillators are in the non aging catagory. For example what about the HP 10811 or the Stanford Research SC 10? The plot on Brooks Shrea's web page for his GPSDO shows linear aging on his Austron 1250. See:

Re: [time-nuts] E1938

); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY No oscillators are in the non aging category. However, the E1938 and 10811 are in the RANDOM aging category. As I previously said, the direction of the aging is random. Now you have brought up the so called disciplined

Re: [time-nuts] E1938 phase noise

); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY Richard (Rick) Karlquist said the following on 08/28/2007 12:27 AM: ); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY E1938A phase noise should be similar to 10811, possibly even a little better far

Re: [time-nuts] E1938 phase noise

); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY E1938A phase noise should be similar to 10811, possibly even a little better far out. Short term stability should be similar to 10811 except down around 1 second, where the AFC circuit degrades it a little to 10^11 or so. The

Re: [time-nuts] E1938 phase noise

); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY Hi Rick, thanks so much for providing us with the info, and units! I got mine locked to GPS already as of 30 minutes ago. Said ** Get a sneak peek of the all-new AOL at