Re: [time-nuts] Frequency Counter Choice

On 10/22/2020 11:52 AM, jimlux wrote: >  I wonder if one could implement the protocol using GPIO pins on > something like a Beagleboard or Arduino clone? > > (yes, as a product, with the right connector and line > driver/receivers, etc. - it would cost the same as a Prologix... but > as a hack...)

Re: [time-nuts] Frequency Counter Choice

> >While I love my Prologix adapters, I wonder if one could implement the > >protocol using GPIO pins on something like a Beagleboard or Arduino clone? > >(yes, as a product, with the right connector and line driver/receivers, > >etc. - it would cost the same as a Prologix... but as a hack...) >

Re: [time-nuts] Frequency Counter Choice

Hi …. and now I have a copy :) Bob > On Oct 22, 2020, at 6:12 PM, Attila Kinali wrote: > > On Thu, 22 Oct 2020 13:29:07 -0400 > Bob kb8tq wrote: > >> There is a paper running around behind the IEEE paywall by Collins that >> details >> one approach to designing multi-stage limiters. There

Re: [time-nuts] SMPS or conventional?

I suspect that one of the main issues these days is the quality of the module - there is a lot of unbranded stuff out there of unknown quality. Cooling a rubidium is probably a relatively easy life for a peltier since there are limited temperature changes, but I would still make sure that I

Re: [time-nuts] 5065A Rb Cavity RX - Varactor repair?

Am 22.10.20 um 23:54 schrieb Richard (Rick) Karlquist: I suspect that the stock 5065 chain has better phase noise than this chip.  I know for sure that you can get much better phase noise than this chip by using conventional architectures. Of course they are more complicated, etc.  Just wanted

Re: [time-nuts] 5065A Rb Cavity RX - Varactor repair?

I doubt that the SRD is the problem. It's just the last thing in the chain, and a number of things ahead of it all have to work right first. I'd look first at any connections and wiring between various sections, and jiggle things around to see if the symptoms can return. Next, if ICs and

Re: [time-nuts] SMPS or conventional?

If the drive current ripple is too high fatigue failure from cyclic thermomechanical stress can be significant. Bruce > On 23 October 2020 at 10:37 ed breya wrote: > > > Regarding TEC life, in my experience, what wrecks them the most is > cooling applications where the cold side is below the

Re: [time-nuts] Frequency Counter Choice

On Thu, 22 Oct 2020 13:29:07 -0400 Bob kb8tq wrote: > There is a paper running around behind the IEEE paywall by Collins that > details > one approach to designing multi-stage limiters. There are other ways to do > it. > The key is to not go to crazy all in one stage. You can find a

Re: [time-nuts] 5065A Rb Cavity RX - Varactor repair?

I suspect that the stock 5065 chain has better phase noise than this chip. I know for sure that you can get much better phase noise than this chip by using conventional architectures. Of course they are more complicated, etc. Just wanted to put this chip in perspective. Rick N6RK On

Re: [time-nuts] SMPS or conventional?

Regarding TEC life, in my experience, what wrecks them the most is cooling applications where the cold side is below the dew point, and water condenses out onto and into the TEC Peltier array. This eventually rots the elements from corrosion and electrolysis, until something craps out. If the

Re: [time-nuts] 5065A Rb Cavity Rx - SRD repair

Hi The SRD is not easily accessible. Digging in to get it is going to involve a bit of work. The power level is going going to be a function of the cavity design. Apparently that design is “non-standard” so any number will be a guess. The 5065 manual shows typical RF voltage levels into the

[time-nuts] 5065A Rb Cavity Rx - SRD repair

I see. Is the SRD in the Rx module accessible at all? What type of package is it? Is it possible to dismantle the Rx unit without risk of cracking the glass enevlope? Does anybody know the power level at 6 GHz? BR  Ulf Kylenfall  SM6GXV 

Re: [time-nuts] 5065A Rb Cavity RX - Varactor repair?

I would tend to agree with the assessment that the SRD is not a high failure rate item. Also, it could experience a faux failure where the fixturing of it corroded such that it was not making good electrical contact any more, but the underlying diode was still good. Cleaning up the contact area

Re: [time-nuts] Frequency Counter Choice

Hi One approach to a mixer setup is the DMTD (dual mixer time difference). It has a “little cousin” that also does very will running one mixer instead of two. The limit there being that you need to be able to tune one or both the devices you are testing to get a beat note in the 2 to 10 Hz

Re: [time-nuts] Frequency Counter Choice

In days of yore + DOS, I implemented a GPIB control by bit-banging a parallel printer port. Those were the days Andy www.g4jnt.com Virus-free. www.avg.com

Re: [time-nuts] Frequency Counter Choice

On Thu, 22 Oct 2020 11:50:08 + Giorgio Barinetti wrote: > Choices are many, but I'll try to avoid the "older" machines lile 5370 or > 5335. The 531xx series seems nice ( money apart ) > But again : which one between the 3 ? 53131, 53132 or 53181 ? Maybe try to get hold of one of the

[time-nuts] 5065A Rb Cavity RX - Varactor repair?

Ulf, I have never had a 5065A with a bad or malfunctioning step recovery diode in the physics package. MANY other problems are more likely the cause. Cheers, Corby ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to

Re: [time-nuts] Frequency Counter Choice

On 10/22/20 8:29 AM, Tom Van Baak wrote: 3) Instead of replacing the front panel readout, instead do all your comms over SCPI, to the point where you have created a virtual instrument, not unlike some of the logic analyzer or 'scope PC apps. This solution would be very welcome by lots

Re: [time-nuts] Frequency Counter Choice

Mark, Yes, the VFD on those counters do seem to have a limited lifetime. I have some 20 years old that are getting hard to read in bright light. If the VFD dies, yes, the counter will continue to measure just fine, not only all the serial talk-only data output, but the full capability of

Re: [time-nuts] Frequency Counter Choice

As a newbie to nuttery I would like to throw my brief experiences into the mix. When I started down this slippery slope I was using a HP5386A frequency counter because I had one. It was entertaining for a short period of time. I then acquired a HP5372A which for hooking up to Timelabs and running

Re: [time-nuts] Frequency Counter Choice

Hi Provided you can get a few key parameters set up (= enable the serial port / set baud rates), it should run just fine without the display. You would need to do some GPIB fiddling to set various modes. Bob > On Oct 22, 2020, at 10:22 AM, Mark Spencer wrote: > > I am just curious how

[time-nuts] Frequency Counter Choice

Hi Bob, Nice explanation. I'll see what I can do to find a 53132. Maybe, in the meantime, if I'll be lucky to find a 5370, I'll play on it. Regarding the mixer based setup, I'm already in progress for setting up a suitable test jig. Please point to some information, if you have it

Re: [time-nuts] 5065A Rb Cavity RX - Varactor repair?

Hi The device in the cavity that takes the 60 MHz up to 6.x GHz is a step recovery diode ( SRD ). The actual device used (apparently) was unique to the 5065. One proposed “fix” is to eliminate the whole synth / multiply empire and replace it with a very high resolution DDS generating the 6.x

Re: [time-nuts] Frequency Counter Choice

Hi, Small correction, 5371A and 5370A are different beasts. The 5370A has 20 ps resolution and the 5371A has 200 ps resolution. So, the 5371A is about the same performance as the 53132A at 150 ps resolution. I work with 5372A which is essentially a 5371A with hardware histogram and a few other

Re: [time-nuts] Frequency Counter Choice

I am just curious how viable would it be to use a 531xx series counter with Timelab if the counter display has failed ? Thanks in advance Mark Spencer m...@alignedsolutions.com 604 762 4099 > On Oct 22, 2020, at 6:36 AM, Bob kb8tq wrote: > > Hi > >> On Oct 22, 2020, at 7:50 AM, Giorgio

[time-nuts] 5065A Rb Cavity RX - Varactor repair?

Strolled into my little lab only to find the 5065A's Red Integrator Limit  light on. Control negative fsd. PhotoCurrent OK. No 2nd harmonic. Was just about to power off and start to disassemble the unit. All of a sudden, the Integrator light went out. Control went to zero and by pressing

Re: [time-nuts] Frequency Counter Choice

Avoid the 53181A; too limited. Both the 53131A / 53132A are "universal" counters so they do frequency, period, time interval, and lots more. They are very useful counters. The rs232 talk-only mode makes it very easy to collect data on a PC. No programming required. The 53132A has a bit higher

Re: [time-nuts] Frequency Counter Choice

Hi > On Oct 22, 2020, at 7:50 AM, Giorgio Barinetti wrote: > > Hi, > > As a newbie in the field, I've collected, by chance, some frequency standards. > > Now is the time to measure them, and see how they perform. > > I've inherited a 5371, but something tells me that is not the right >

Re: [time-nuts] SMPS or conventional?

Hi The magnetic field sensitivity is dependent on a lot of things. Strangely enough, the higher the C field, the more sensitive the physics package is ( yes, that’s weird …). All Rb’s incorporate shielding to reduce the external field impact. Since the shielding is rarely perfect, there are

Re: [time-nuts] SMPS or conventional?

Hi TEC’s are indeed prone to wear out. That said, so is a compressor ….. Bob > On Oct 22, 2020, at 12:36 AM, Hal Murray wrote: > >> like with TEC heat/cool capability > > What's the typical MTBF of TEC coolers? How much does it depend on how much > power you put through them? > > -- >

[time-nuts] Frequency Counter Choice

Hi, As a newbie in the field, I've collected, by chance, some frequency standards. Now is the time to measure them, and see how they perform. I've inherited a 5371, but something tells me that is not the right instrument - and maybe is even faulty. So, I'm in the need to buy a counter to use

Re: [time-nuts] IEEE 1588 PTP support on raspberry pi 4 compute module

On Thu, 22 Oct 2020 at 01:53, Magnus Danielson wrote: > Hi, > > Yeah, poor CPU time-stamping can be worse than network biases, but > hardware time-stamping and careful use of good time-stamps handles most > of the host issues. Then network biases becomes the dominant problem > unless one does

Re: [time-nuts] IEEE 1588 PTP support on raspberry pi 4 compute module

Hello Bob, On Thu, 22 Oct 2020 at 01:53, Bob kb8tq wrote: > Hi > > Simply that you can get into the 10’s of microseconds (done in many times) > with > NTP. If the local LAN is streaming video, it needs 1588 switches / routers > to do > better than that. > That is all true, however not every

Re: [time-nuts] IEEE 1588 PTP support on raspberry pi 4 compute module

(this message is half redundant now since there were some more posts since I typed it) On Wednesday, 21 October 2020, Hal Murray wrote: > > > Even if the network is lightly loaded, there can be asymmetry in CPU > processing delays. And that is why software timestamps (in a non-realtime OS) are

Re: [time-nuts] SMPS or conventional?

Hi, The magnetic field issue has bothered me a little too, but I don't know whether it has a practical effect. Maybe putting a fan in a plastic or aluminium box close to the Rb might show something - unless someone already knows the effects. I have a compass on the bench beside the LPRO,

Re: [time-nuts] SMPS or conventional?

> like with TEC heat/cool capability What's the typical MTBF of TEC coolers? How much does it depend on how much power you put through them? -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@lists.febo.com To

Re: [time-nuts] IEEE 1588 PTP support on raspberry pi 4 compute module

Wojciech Owczarek writes: >This topic was bound to hit time-nuts - great to see Rpi finally going for >a MAC/PHY with hardware timestamp support and hopefully future full-sized >models will follow suit. Unfortunately for most chips other than Intel and >enterprise comms vendors like