Re: [time-nuts] quartz / liquid nitrogen

Very true Sent from my iPhone > On Apr 3, 2018, at 7:51 PM, Bob kb8tq wrote: > > Hi > > If the objective is great phase noise far removed from carrier, there’s a > gotcha. > > Let’s say you have a 10 dbm source at room and it’s broadband is at KTB of > -174 + 1db. > That

Re: [time-nuts] Harrison's birthday

Jim, The Harrison google doodle is attached for those that missed it [1]. A couple of comments: 1) One alert reader pointed out that the clocks are stopped. Google is capable of clever JavaScript animations, so the least they could do is have the clocks in motion. It would be especially

Re: [time-nuts] quartz / liquid nitrogen

Hi If the objective is great phase noise far removed from carrier, there’s a gotcha. Let’s say you have a 10 dbm source at room and it’s broadband is at KTB of -174 + 1db. That gives you -183 dbc. You cool your oscillator to whatever and KTB goes down to -194. You do a bang up job at that

Re: [time-nuts] new longwave time service planned in India

Pieter That is quite a surprise that a country is setting up a long wave system these days. They still have to raise the money but it seems like a semi-private arrangement. Even more interesting is they suggest 3 locations. Something to try to find in the VLF bands some day in the future. Regards

Re: [time-nuts] Cheap jitter measurements

On the practical side, the 5345 is HEAVY due to its older technology—doing what it does with first-generation ICs required HP jam an enormous amount of circuitry into a fairly small physical package. Jeremy N6WFO On Tue, Apr 3, 2018 at 2:39 PM Bob kb8tq wrote: > Hi > > I would

[time-nuts] Open day at the National Physical Laboratory (NPL) on Thursday 17 May 2018.

NPL opens their doors to the public once every 2 years. It is well worth going. Tickets are only 3.00 each, and that money is donated to a cancer charity. More details at http://www.npl.co.uk/open-house/ To make the most of it, you need to 1) Arrive early (14:00) 2) Leave when they close

[time-nuts] new longwave time service planned in India

Hi, Apparently India plans to build two longwave transmitters for a national time signal service: http://www.thehindu.com/todays-paper/tp-national/coming-huge-towers-to-publicise-right-time/article23377284.ece No technical details such as frequency and modulation are given, nor whether the

Re: [time-nuts] Cheap jitter measurements

Hi I would add the HP 5335 to the list of counters to look for. The surplus market can be really weird. A 5334 *should* be less than a 5335, but on any given day, that may not be true. The 5370 and 5345 are also worth looking for. Target price (at least for me) wold be < $150 for a quick buy

Re: [time-nuts] Cheap jitter measurements

Gary There is a Blast from the past the PIC TIC. Richard McCorkle did it and in its time was widely popular. He helped me on many projects so I included his boards with my board orders. Not being a time nut I never took a closer look at his board. Having recently revisited the subject for

Re: [time-nuts] Cheap jitter measurements

g...@rellim.com said: > With care I can measure GPS jitter on a RasPi to a bit over 300 nano sec > resolution. That is the smallest increment of the RasPi 3B clock with a > 64-bit kernel. That is clearly not time-nuts accuracy. > What would you guys suggest as the cheapest way to see jitter

Re: [time-nuts] Cheap jitter measurements

Hi Gary, One solution is to look for used hp, Fluke, or Racal time interval counters on eBay. 1 or 2 ns is pretty easy to find with a $100 or $200 budget. Look for Racal 1992 or hp 5334B as examples. If you plan to collect lots of data, you'll want GPIB (or RS232 / USB) connections to a PC and

Re: [time-nuts] Cheap jitter measurements

Find a nice used 5370/5371? :) There is a 5371 on ebay for $250 at the moment. On Tue, Apr 3, 2018 at 1:47 PM, Gary E. Miller wrote: > Time-nuts! > > With care I can measure GPS jitter on a RasPi to a bit over 300 nano sec > resolution. That is the smallest increment of the

Re: [time-nuts] Cheap jitter measurements

On Tue, 3 Apr 2018 10:47:37 -0700 "Gary E. Miller" wrote: > What would you guys suggest as the cheapest way to see jitter down to > around 1 nano second? Look at Nick Sayers GPSDO and his interpolator. You wont get any cheaper than that. Next best thing is to use a TDC7200

Re: [time-nuts] quartz / liquid nitrogen

Hi Mark: When Aetech started to make their own Tunnel Diodes there was a problem with the neck breaking. Note they were made by alloying a ball of metal onto a highly doped chip, bonding from the lip of the ceramic package to the ball then on to the opposite lip, then etching the chip away

[time-nuts] Cheap jitter measurements

Time-nuts! With care I can measure GPS jitter on a RasPi to a bit over 300 nano sec resolution. That is the smallest increment of the RasPi 3B clock with a 64-bit kernel. That is clearly not time-nuts accuracy. What would you guys suggest as the cheapest way to see jitter down to around 1 nano

[time-nuts] Datum 1000B

Does anyone have any nuts and bolts (disassembly?) experience they can share regarding fixing a Datum 1000B pn 05818-115 (4x10MHz) which has a manual frequency pot and which will not adjust to 10,000,000.000 MHz? It will actually go as low as “10,000,000.2890”, but no lower. (The unit does

Re: [time-nuts] quartz / liquid nitrogen

Many years ago, circa 1977, I was moved to try some crude tests on a few semiconductor devices at LN2 temperature (77K). These tests were very crude, involving dunking the parts into the LN2 bath, and many failed outright. Most of the devices tested were in plastic packages. Here are the

Re: [time-nuts] quartz / liquid nitrogen

Hi > On Apr 2, 2018, at 11:18 PM, jimlux wrote: > > On 4/2/18 1:39 PM, Hal Murray wrote: >>> If not Nitrogen, how about dry ice (-109F -78C)? >> Dry ice is relatively easy to get. It wouldn't be hard to try a quick >> experiment. > > > CTE mismatch in packages will be a

Re: [time-nuts] TV Signals as a frequency reference

Yeah, that's pretty much the story around the country. I also have some monitoring software (monitoring PSIP, video and audio data, not specifically for monitoring STT packets) that I run on the Denver and Cheyenne stations 24 hours a day. Very few have set their GPS-UTC offset to 18 seconds.