Author Topic: Test Equipment Anonymous (TEA) group therapy thread  (Read 1708214 times)

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Online Specmaster

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #32950 on: June 11, 2019, 04:58:23 pm »
Fair points. This is mostly for checking TX / VCO frequency which isn't exactly terrible as everyone stays a KHz or so away from band edges. Filters are as narrow as 200Hz. Need something reliable as my efforts to replace the transformer on the 9915 aren't going particularly well so far. Bought one anyway. It's not exactly expensive, especially when you don't pay VAT on it :-DD. TTi PFM3000. Review coming tomorrow.
Radio Cruncher uses one of those in his radio restoration videos and he does some ham gear from time to time, he seems to think its ok, I'd rather stick with my tf9300 however as I'm sure that has a better spec overall.
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Offline bitseeker

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #32951 on: June 11, 2019, 05:22:21 pm »
I've used that OCXO to adjust the XO frequency of my frequency meter, and local gravity clearly affects the frequency; that 0.5Hz delta is repeatable.

Previously it was 3.2Hz off (i.e. 3.2ppm, well within spec), but now it seems that there are two stable modes:



Given how little I had to tweak the trimcap, my suspicion is that the frequency changes because the trimcap's vanes are closer/further apart depending on orientation :)

Yes, I am guilty of over-interpreting the significance of the displayed frequency :)

That's actually normal for a crystal oscillator. I believe Dave did a video on it.

Ah, yes. Here it is:

I TEA.
 

Online bd139

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #32952 on: June 11, 2019, 05:39:19 pm »
Being Philips, something has probably broken off inside and resting on the capacitor  :-DD

Actually it is remarkably clean in and out, and I haven't even felt an overwhelming urge to replace the few big electrolytics.

The spec is +-10Hz, so +-0.4Hz isn't bad :)

I think I’ve had to replace at least one in everything Philips I’ve owned. That’s not bad at all. I noticed that some of the MEMS TCXOs have slightly different frequency if you bash them around a bit as well so it’s kind of inevitable really.

Fair points. This is mostly for checking TX / VCO frequency which isn't exactly terrible as everyone stays a KHz or so away from band edges. Filters are as narrow as 200Hz. Need something reliable as my efforts to replace the transformer on the 9915 aren't going particularly well so far. Bought one anyway. It's not exactly expensive, especially when you don't pay VAT on it :-DD. TTi PFM3000. Review coming tomorrow.
Radio Cruncher uses one of those in his radio restoration videos and he does some ham gear from time to time, he seems to think its ok, I'd rather stick with my tf9300 however as I'm sure that has a better spec overall.

Yeah on paper it’s not as good as a TF930. It is however smaller which is a big win for me at the moment. I did consider buying another full price TF930 but when I wrote down what I needed, the PFM was fine.

And yes I shouldn’t have sold the TF930  :-DD

I've used that OCXO to adjust the XO frequency of my frequency meter, and local gravity clearly affects the frequency; that 0.5Hz delta is repeatable.

Previously it was 3.2Hz off (i.e. 3.2ppm, well within spec), but now it seems that there are two stable modes:



Given how little I had to tweak the trimcap, my suspicion is that the frequency changes because the trimcap's vanes are closer/further apart depending on orientation :)

Yes, I am guilty of over-interpreting the significance of the displayed frequency :)

That's actually normal for a crystal oscillator. I believe Dave did a video on it.

Ah, yes. Here it is:



Interesting. Will watch that this evening.

I’ve had some problems with VXOs and mechanical stability. Wonder if that will clear up some thoughts.
 

Offline mnementh

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #32953 on: June 11, 2019, 05:41:21 pm »
When gravity fails, and negativity don't pull you through...  :-DD

mnem
[/RANDOM MODE]
« Last Edit: June 11, 2019, 05:43:31 pm by mnementh »
 

Offline tggzzz

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #32954 on: June 11, 2019, 06:10:32 pm »
I've used that OCXO to adjust the XO frequency of my frequency meter, and local gravity clearly affects the frequency; that 0.5Hz delta is repeatable.

Previously it was 3.2Hz off (i.e. 3.2ppm, well within spec), but now it seems that there are two stable modes:



Given how little I had to tweak the trimcap, my suspicion is that the frequency changes because the trimcap's vanes are closer/further apart depending on orientation :)

Yes, I am guilty of over-interpreting the significance of the displayed frequency :)

That's actually normal for a crystal oscillator. I believe Dave did a video on it.

Ah, yes. Here it is:



That's showing a 1 or 2 ppb effect. I'm seeing a 500 ppb change. I'll stick to the trimcap being the cause.
There are lies, damned lies, statistics - and ADC/DAC specs.
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Offline kj7e

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #32955 on: June 11, 2019, 06:19:03 pm »
Gravity and how it warps the crystal changes the resonate frequency slightly.  Crystal references are positionally sensitive by nature.  Some crystals are much more sensitive to this effect than others.
« Last Edit: June 11, 2019, 06:21:30 pm by kj7e »
 

Online bd139

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #32956 on: June 11, 2019, 06:19:46 pm »
What sort of trim cap is it out of interest? Plastic/ceramic/air?
 

Offline tggzzz

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #32957 on: June 11, 2019, 07:18:41 pm »
What sort of trim cap is it out of interest? Plastic/ceramic/air?

Appropriately cheap and nasty, as in the pic.

Note the red mark from a staedler lumocolour fine pen. Changing the frequency by 3ppm was done by rotating that mark by less than the width of the mark, i.e. bugger all.

Quite frankly I'm surprised the frequency didn't change every time I thumped the case :)



There are lies, damned lies, statistics - and ADC/DAC specs.
Glider pilot's aphorism: "there is no substitute for span". Retort: "There is a substitute: skill+imagination. But you can buy span".
Having fun doing more, with less
 

Offline mnementh

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #32958 on: June 11, 2019, 07:19:10 pm »
[OT:Shameless slAmazon plug]

   If you're moving towards ceramic non-stick and away from potentially-carcinogenic Teflon as I am, Amazon has a $9 off deal on the forged GreenPan 8" Chatham right now. This is GreenPan's 2nd or 3rd after their top-of-the-line Venice Pro, and highly-reviewed for many years now. For those who enjoy cooking, the 8" is usually your go-to pan for almost every little thing; getting this one for $21 shipped is a good deal, even if you have other better cookware.

[/Shameless slAmazon plug]

mnem
*Cooking-ily*

 

Offline mnementh

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #32959 on: June 11, 2019, 07:22:34 pm »
What sort of trim cap is it out of interest? Plastic/ceramic/air?
   Appropriately cheap and nasty, as in the pic. Note the red mark from a staedler lumocolour fine pen. Changing the frequency by 3ppm was done by rotating that mark by less than the width of the mark, i.e. bugger all. Quite frankly I'm surprised the frequency didn't change every time I thumped the case :)

*Farts in your general direction* How many PPM was that?  :-DD   So... planning to replace with a precision ceramic?

mnem
 :-/O
 

Online bd139

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #32960 on: June 11, 2019, 07:24:07 pm »
What sort of trim cap is it out of interest? Plastic/ceramic/air?

Appropriately cheap and nasty, as in the pic.

Note the red mark from a staedler lumocolour fine pen. Changing the frequency by 3ppm was done by rotating that mark by less than the width of the mark, i.e. bugger all.

Quite frankly I'm surprised the frequency didn't change every time I thumped the case :)



Those are surprisingly not cheap but are nasty. £5 a go. Not sure why.

Trying to do something stupid here. Have a 20MHz Crystal and seeing if I can get it to oscillate at 5th harmonic without futzing with multiplier stages.
« Last Edit: June 11, 2019, 07:26:01 pm by bd139 »
 

Offline GregDunn

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #32961 on: June 11, 2019, 07:25:39 pm »
That's actually normal for a crystal oscillator. I believe Dave did a video on it.

Ah, yes. Here it is:



I'm disappointed - I was expecting Dave to flip the frequency standard over to see whether it affected the output frequency.   ;D
 

Offline tggzzz

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #32962 on: June 11, 2019, 08:03:58 pm »
What sort of trim cap is it out of interest? Plastic/ceramic/air?
   Appropriately cheap and nasty, as in the pic. Note the red mark from a staedler lumocolour fine pen. Changing the frequency by 3ppm was done by rotating that mark by less than the width of the mark, i.e. bugger all. Quite frankly I'm surprised the frequency didn't change every time I thumped the case :)

*Farts in your general direction* How many PPM was that?  :-DD   So... planning to replace with a precision ceramic?

Er, 3ppm.

And no; if I need more than the meter's basic accuracy, I'd use a decent external source and do a "ratio a/b". Decent means either that OCXO or a Ublox GPS 1pps output.

I'll leave phase noise measurement to others.
There are lies, damned lies, statistics - and ADC/DAC specs.
Glider pilot's aphorism: "there is no substitute for span". Retort: "There is a substitute: skill+imagination. But you can buy span".
Having fun doing more, with less
 

Online med6753

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #32963 on: June 11, 2019, 08:26:35 pm »
Going to be taking a break from any other TEA projects for a while. Need to get other things down around here like some work on the cars and paint the kitchen, which I've been putting off and I want to get done. I will be checking in but probably not contributing much. Then again, I could say "screw it" and start working on something else. Got a few projects lined up. When you're retired and your own boss you can do stuff like that. I love being retired.  :-DD

You young guys in the U.S. Keep working to pay for my Social Security. It is great getting those checks every month and not lift one finger to earn it.  :P :-DD   
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Offline mnementh

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #32964 on: June 11, 2019, 08:31:12 pm »
*Farts in your general direction* How many PPM was that?  :-DD   So... planning to replace with a precision ceramic?

Er, 3ppm.

And no; if I need more than the meter's basic accuracy, I'd use a decent external source and do a "ratio a/b". Decent means either that OCXO or a Ublox GPS 1pps output.

I'll leave phase noise measurement to others.
Oh, okay... the way you were talking, it sounded like you were questioning the fundamental stability of that trimmer. If you don't think there's a fault, then of course don't eff with it.  :-+

mnem
mrrp?
 

Offline tggzzz

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #32965 on: June 11, 2019, 08:35:10 pm »
What sort of trim cap is it out of interest? Plastic/ceramic/air?

Appropriately cheap and nasty, as in the pic.

Note the red mark from a staedler lumocolour fine pen. Changing the frequency by 3ppm was done by rotating that mark by less than the width of the mark, i.e. bugger all.

Quite frankly I'm surprised the frequency didn't change every time I thumped the case :)



Those are surprisingly not cheap but are nasty. £5 a go. Not sure why.

Trying to do something stupid here. Have a 20MHz Crystal and seeing if I can get it to oscillate at 5th harmonic without futzing with multiplier stages.

Cheap is relative :)

For bonus points, use nuvistor valves to multiply a 10MHz crystal to 500MHz :) You've seen pictures of how to do it, hee hee.
There are lies, damned lies, statistics - and ADC/DAC specs.
Glider pilot's aphorism: "there is no substitute for span". Retort: "There is a substitute: skill+imagination. But you can buy span".
Having fun doing more, with less
 

Online bd139

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #32966 on: June 11, 2019, 08:59:10 pm »
Cheap is relative :)

For bonus points, use nuvistor valves to multiply a 10MHz crystal to 500MHz :) You've seen pictures of how to do it, hee hee.

Yes that is quite impressive that one is.

Well it turned out to be pretty easy to get a 20MHz crystal to do a rodeo at 100MHz. I can't take credit for this as it's lifted from VU2ESE's 2nd LO design for the W7ZOI SA. I'll wait until tomorrow before I celebrate too hard.

Picture below...
« Last Edit: June 11, 2019, 09:03:31 pm by bd139 »
 

Offline VK5RC

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #32967 on: June 11, 2019, 09:00:32 pm »
tggzzz - is that the main ref x-tal just sitting on the pcb - would a little overcoat (thermal insulation) help its stability?
Whoah! Watch where that landed we might need it later.
 

Offline Neomys Sapiens

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #32968 on: June 11, 2019, 09:39:42 pm »
Really nice pile of things for just the cost of shipping. A lot of GR-874 stuff, of which I had none. The trombone line is pretty cool, and apparently quite expensive according to some fleabay sellers...

This reminds me of something:
Is anyone of you guys at the HAM Radio in Friedrichshafen (Germany) around 21st of June?

https://www.hamradio-friedrichshafen.com/

I'll be there on Friday (21.6.2019)

Mounty
Not that I would not like, but I'm not sure yet whether I will manage it due to workload. I will update here.
 

Offline tggzzz

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #32969 on: June 11, 2019, 09:41:53 pm »
tggzzz - is that the main ref x-tal just sitting on the pcb - would a little overcoat (thermal insulation) help its stability?

I believe it is, but that attempting to improve it would be like putting lipstick on a pig.

There is some form of (irrelevant) option to remove that XTAL and insert a "better" reference on an internal PCB.

More irrititatingly, it looks like there are poorly understood (RTFM? Wazzat?) limitations on the "ratio a/b" measurements with B=10MHz  It appears that the ratio is inoperative over ~20MHz even though stuffing the same 10MHz input into the "external ref in" back panel socket allows "freq a" to measure 100MHz as expected.

Not sure I can be bothered to work it out. Tomorrow is a long trog to pick up the scanning tunnelling microscope and a leopard. I hope I'll be able to dodge the unseasonably inclement weather.
There are lies, damned lies, statistics - and ADC/DAC specs.
Glider pilot's aphorism: "there is no substitute for span". Retort: "There is a substitute: skill+imagination. But you can buy span".
Having fun doing more, with less
 

Online Specmaster

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #32970 on: June 11, 2019, 09:45:35 pm »
Going to be taking a break from any other TEA projects for a while. Need to get other things down around here like some work on the cars and paint the kitchen, which I've been putting off and I want to get done. I will be checking in but probably not contributing much. Then again, I could say "screw it" and start working on something else. Got a few projects lined up. When you're retired and your own boss you can do stuff like that. I love being retired.  :-DD

You young guys in the U.S. Keep working to pay for my Social Security. It is great getting those checks every month and not lift one finger to earn it.  :P :-DD   
Good luck with the "other" projects, yes I too enjoy being retired but never forget that those checks we get, we also paid in for over the years so we are more than entitled to them   :-DD
Who let Murphy in?
 

Online bd139

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #32971 on: June 11, 2019, 10:08:02 pm »
« Last Edit: June 11, 2019, 10:09:56 pm by bd139 »
 

Online Specmaster

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #32972 on: June 11, 2019, 10:15:45 pm »
Hmmm Smith 1 looked good  :-DD :-DD
Who let Murphy in?
 

Offline wch

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #32973 on: June 11, 2019, 10:29:47 pm »

Tomorrow is a long trog to pick up the scanning tunnelling microscope and a leopard.


I do not hang out in many places in which scanning tunneling microscope and leopard are used in the same sentence, let alone included as items in a to-do list. 

 :-DD   :-DD 
proceed until apprehended
 

Offline tggzzz

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #32974 on: June 11, 2019, 11:11:57 pm »
The leopard has been on my to do list for decades, and recently I found someone that should do a good job on it. He's an old interesting guy that used to fly microlights, and wants to see my gharial.

Not sure what to do with the leopard; it is too large for its traditional location on the back of the small sofa (plus I don't want daughter's dog to find it too interesting). I'll probably try to invent a way to splat it across the stairway wall.
There are lies, damned lies, statistics - and ADC/DAC specs.
Glider pilot's aphorism: "there is no substitute for span". Retort: "There is a substitute: skill+imagination. But you can buy span".
Having fun doing more, with less
 


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