On Mon, 18 Dec 2023 at 21:51, Reginald Beardsley via <pulaskite= [email protected]> wrote: Chris,
It is, but I'm in the US.
Resistors are easy. It's the inductors and capacitors that are hard.
However, an SMD string of capacitors which can be trimmed by hand by adding a capacitor in parallel should be a pretty simple PCB layout. Have them assembled without the trimmers by JLCPCB. Measure and add the appropriate values.
Why would you bother trimming? As long as a value is known, it doesn¡¯t matter if it¡¯s 10 uF or 10.16 uF.? What is important is stability.?
It's not to the standard I had in mind when I posted, but it would be a very practical way to help people self cal their kit. And with a sensitive bridge one could be circulated to cal personal versions.
There are similar things happened in the UK among the microwave community.?
1) I can not give a direct link, but if you go to?
select Support, then Free Advice, you will see a list of people, including myself, that list equipment that they will allow others to use.?
2) People take test equipment to the microwave roundtables. The one at BT Labs? Martlesham used to have access to a lot of calibrated equipment from BT, but that¡¯s no longer the case, but people will turn up with spectrum analyzers and similar.
Unless optical (eg laser), or something else particularly exotic, it¡¯s pointless worrying about frequency standards.?
Have Fun
Reg
Dave?
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These do not like being fed more than 10 V. Here's a 1000 trace average at 1 dB/div with 10.06 V according to the PSU display. And another display at 12 V 500 trace average. The output MMICs need a separate regulator. If I go below 10 V it shuts down the zener.
As this is at the resolution of the 8560A I can't say anything about the residual wiggles as I have not attempted to verify the 8560A flatness.
Despite the low cost, with a little bit of effort this seems to me a pretty good source for a cal club meeting.
Have Fun!
Reg
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Re: Does anyone have any experience with these log detectors?
Reg,
When I worked on Marine radios in the 1970's many problems was caused by problems with the antenna installation. That timeframe corresponded to the transition of Marine communications from the 2-4 MHz AM band radios to the 156-157 MHz FM band radios.
I recommended to the boaters to purchase an FM radio instead of repairing the AM sets but they were short sighted. I spent a good amount of time matching the output of the AM sets to the electrically short antenna. I recall I have to move taps on the output coil and then adjust the matching network to get the correct plate current.
Mike N2MS
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On 12/16/2023 2:16 PM EST Reginald Beardsley via groups.io <pulaskite@...> wrote:
ROFL!
I wanted to retire to a Spray type boat working on boats and marine radios. Too old now and stuck on land.
My Field Day kit has:
nanoVNA H4
4x tinySA
LCR/Transistor tester
diode noise source
2x directional couplers
LNA
OXCO reference
Owon HDS272S 70 MHz dual trace DSO & AWG
misc DMMs
All in a Harbor Freight "Pelican" style case.
That's all under $1000 USD which blows my mind. Oh, to have had that when I was 30 something. I can't think of an electronics related problem on a cruising boat that would not diagnose.
Have Fun!
Reg
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Re: Does anyone have any experience with these log detectors?
Eric,
Thanks for the advice. I have been testing out with radio in the SSB mode and the peak power corresponds with the readings I get using an oscilloscope.
I constructed a 40dB power attenuator and will use it in my 10 watt QRP portable kit. The attenuator outputs at a 0dBM level with 10 watts input so I assume that should be a sufficient margin for the input of the TinySA which specified with a maximum level of +10dBm.
Mike N2MS
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On 12/16/2023 12:14 PM EST Erik Kaashoek <erik@...> wrote:
No, set to zero span and at the carrier frequency. The resolution filter should be maximum width
This makes the tinysa a tuned power meter.
Set the trace to max hold to measure peak power
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The voltage and resistance requirements for RF are adequately met by more economical standards, e.g. LM399 and some 20 ppm resistors. Crazy not to include them. The CTI OXCOs are within a few ppb in 10 minutes.
FWIW Here's the spectrum of a cheap ebay diode noise source. It needs a 2nd regulator, but I'd say not bad for under $30. Very flat if you're patient enough to find the right voltage setting.
Have Fun!
Reg
On Tuesday, December 19, 2023 at 02:37:26 PM CST, Erik Kaashoek <erik@...> wrote:
The purpose of the "cal club" is to improve the ability to have accurate references or do accurate measurements in the RF domain
What not to include: voltage references and resistors. These are addressed by the volt nut community
That leaves:
L and C standards to verify calibration of LC meters.?
As long as these are stable and have been measured at known temperatures and frequencies, the exact value is unimportant, as long as they cover a certain range of values
Impedance standards in a 50 ohm setting with agreed interconnects to verify calibration of VNA's and local calibration standards
Again, as long as these have been characterized, the actual values are less important as long as they span both the S11 smith chart and relevant S21 variants
Stable and accurate RF sources at some frequencies or a calibrated wide band noise source
Sources with very stable output levels covering a limited frequency range can be build and characterized enabling the level verification of SA and power meters.
Maybe a wide band noise source with calibrated power level is possible?
Frequency references are not useful.
Unless you include a cesium clock anything you ship will be drifting for a long time after being shipped unless being shipped in a on state with strict temperature controll. GPS is probably the best way to do frequency transfer. Including a known good gpsdo may be an option but only for long term stability
Phase stability standard. I'm talking about stability below a Tau of 100 s. Possibly 100 s is not feasible due to drift after shipping
A very high stabily oscillator with a well characterized ADEV can be used as a reference for characterizing local reference oscillators
Maybe include a calibrated wide band power meter to verify and calibrate signal sources.
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Re: Looking for a 12v DPDT Relay for at Antenna switching
The relay almost everyone uses in all the QRO switches is a Schrack?RT424012. Available everywhere for $4.
Gary NA6O
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The purpose of the "cal club" is to improve the ability to have accurate references or do accurate measurements in the RF domain
What not to include: voltage references and resistors. These are addressed by the volt nut community
That leaves:
L and C standards to verify calibration of LC meters.?
As long as these are stable and have been measured at known temperatures and frequencies, the exact value is unimportant, as long as they cover a certain range of values
Impedance standards in a 50 ohm setting with agreed interconnects to verify calibration of VNA's and local calibration standards
Again, as long as these have been characterized, the actual values are less important as long as they span both the S11 smith chart and relevant S21 variants
Stable and accurate RF sources at some frequencies or a calibrated wide band noise source
Sources with very stable output levels covering a limited frequency range can be build and characterized enabling the level verification of SA and power meters.
Maybe a wide band noise source with calibrated power level is possible?
Frequency references are not useful.
Unless you include a cesium clock anything you ship will be drifting for a long time after being shipped unless being shipped in a on state with strict temperature controll. GPS is probably the best way to do frequency transfer. Including a known good gpsdo may be an option but only for long term stability
Phase stability standard. I'm talking about stability below a Tau of 100 s. Possibly 100 s is not feasible due to drift after shipping
A very high stabily oscillator with a well characterized ADEV can be used as a reference for characterizing local reference oscillators
Maybe include a calibrated wide band power meter to verify and calibrate signal sources.
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Looking for a 12v DPDT Relay for at Antenna switching
I want to to do A/B testing with different amps driving my feedline and just a transformer. I want a long lasting relay that will hold up in my outdoor enclosure.
I want a 12V DPDT relay. I'd like to keep the price under $5.
I had success with? a NEC RSP24H2C12H, but I don't find that available anymore.
?? Does anyone have a favorite they recommend?
??????????????? Thanks, Mikek
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Hey I'm up in Aberdeen, and I have access to a Fluke 8588A (8.5 DMM) as well as quite a few 6.5/7.5 DMMs. I have some old GenRad standard inductors and capacitors for low frequency stuff, as well as a range of cal and verification kits for VNAs of various/limited provenance. I don't fancy circulating my kit, but would happily bring it somewhere local for a meetup, and have checked out kit posted to me for others in the past. Would hapilly participate in a UK round robin so if someone sets it up please let me know.
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On Mon, Dec 18, 2023 at 11:27 PM, Tom Gardner wrote:
On Monday 18 December 2023, Adrian Godwin <artgodwin@...> wrote:
> Sounds interesting. I have a few LM399s but not done the work to make a transfer standard. But it would be very good to get a UK cal group together, for both DC and the stuff Reg is talking about.
>??
In Brizzle, I have a small selection of resistance standards that are meant to be in oil baths, a couple of Sullivan mica capacitors, a well aged Trancell II transfer voltage reference, a Cropico voltage standard, an in-spec Weston standard cell thermometer (sic), a Julie Labs 7decade KVD.
I wonder if there is scope for a big meeting somewhere central, rather than trusting items to the post?
I'd be interested in joining (London, UK).
Interested in frequency domain things, but I don't have a whole lot to contribute that's portable -
?- a Marconi 6910 10MHz-20GHz power sensor (calibration provenance unknown but seems to be in spec against the SA)
?- a calibrated 7GHz from Kirkby Microwave (cal expired 4 days ago, apologies David!)
I've been considering buying a calibrated noise source for noise figure measurements.
If we're posting things around, I have a freshly calibrated (last month) HP 34401A 6 1/2 digit DMM in the lab, along with a decent spectrum analyser (21.2GHz), VNA (6GHz) and signal gen (3.3GHz). Ironically the lab has no view of the sky, and building management were not fans of my proposal to run fibre optic down the corridor, so periodically borrowing a known good frequency source would be really useful.
Kind regards
Patrick
https://blinkenlight.co.uk
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Hi,
wifey and me would fly in.
Tam
With best regards
Tam HANNA
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On 2023. 12. 19. 0:50, Reginald
Beardsley via groups.io wrote:
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Tom et al,
May I suggest to arrange a meeting room at a restaurant or hotel
for a day once a year and everyone bring their cal standards.
With a strong turnout, NPL might do the honors.
Such an event is impossible (at least for me) in the US because
of distance, but in the UK a pair of such weekend events, one
north and one south, would help a lot of people.
Have Fun!
Reg
On Monday, December 18, 2023 at 05:27:30 PM CST, Tom Gardner
<tggzzz@...> wrote:
[snip]
I wonder if there is scope for a big meeting somewhere central,
rather than trusting items to the post?
|
Sounds good,
Can it be a "sub group"
I don¡¯t wish to create any subgroups.
Dave (group owner)?
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Sounds good,
Can it be a "sub group"
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Mobile:?? 0412 299 922
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I'd like to suggest an EMF camp project.
Create a PCB with a set of SMD binary step capacitor pairs such that the preceding 2 can be paralleled to adjust the next step. Have them made with the capacitance too low and space to add capacitors in parallel. Take care to account for jumper inductance. Then have the participants adjust them using a log amplifier detector and bridge.
The last step is to perform absolute calibration by measuring the water temperature rise with it in shunt with a non-inductive 50 ohm load immersed in water at 2 frequencies. It won't yield specific values, but it will deliver accurate and precisely known values if the participants make the effort to match the values.
Have Fun!
Reg
On Monday, December 18, 2023 at 06:16:51 PM CST, Adrian Godwin <artgodwin@...> wrote:
We've wondered before about getting some standards (hired or borrowed) at EMF Camp
The thought from the camp organisers was that hiring wouldn't be justified by the usage (and tbh, a camping event isn't the best place to compare precision standards!) but I think they'd do their best to support a meeting if it wasn't unreasonably expensive.?
Better still might be to ask NPL at one of their regular open days to provide access to some high-end? equipment but they might be wary of creating something that might be swamped by some fringe trade sellers.
The BATC (amateur TV) group used to get an array of expensive RF test gear at their annual conference but I don't know if they still do that.? ?
I do think that although individually we might have only one or two useful instruments, when working together we could put up quite an array. I'm not at all sure what sort of precision we could get to though with perhaps poor climate control and limited time for settling and careful testing.
On Mon, Dec 18, 2023 at 11:50?PM Reginald Beardsley via <pulaskite= [email protected]> wrote: Tom et al, May I suggest to arrange a meeting room at a restaurant or hotel for a day once a year and everyone bring their cal standards. With a strong turnout, NPL might do the honors. Such an event is impossible (at least for me) in the US because of distance, but in the UK a pair of such weekend events, one north and one south, would help a lot of people. Have Fun! Reg On Monday, December 18, 2023 at 05:27:30 PM CST, Tom Gardner < tggzzz@...> wrote: [snip] I wonder if there is scope for a big meeting somewhere central, rather than trusting items to the post?
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Meant to add I can probably provide SMA and
N SOL near metrology grade cal kits that have had the cal
data/factors lost. If someone wanted to cal them against a know
good get to get the data, that might be a great addition.
Bob
On 12/18/23 11:24 AM, Reginald
Beardsley via groups.io wrote:
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Is there any interest here in circulating a set of RF related references? The voltnuts on EEVblog are now in the 3rd round.
A set of voltage references, resistors and a temperature and humidity logger are sent hub and spoke so that each time it's sent out it's been checked.
I have in mind a set of capacitors, inductors and resistors, power meter calibrator, OXCO/GPSDO, SMA and N cal kits, etc of sufficient accuracy to calibrate common hobbyist instruments.
Have Fun!
Reg
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Here in New England we are blessed to have
the nice folks from R&S come with their latest high end test
equipment to our Microwave Update conference and its Northeast
equivalent so we can all test the goodies we bought at the
conference. I usually bring a set of my well dated HP gear for the
'also rans' to test with and relieve some of the pressure on the
R&S folks. Perhaps folks could also bring standards. A well
settled GPSDO would be easy enough, some other standards would
also be nice to have.? Maybe the Cesium and Rubidium standards as
well. Would be a delight to see a bank of counters all running
against a single standard for two days of the conference for
example.
Bob
On 12/18/23 6:50 PM, Reginald Beardsley
via groups.io wrote:
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Show quoted text
Tom et al,
May I suggest to arrange a meeting room at a restaurant or hotel
for a day once a year and everyone bring their cal standards.
With a strong turnout, NPL might do the honors.
Such an event is impossible (at least for me) in the US because
of distance, but in the UK a pair of such weekend events, one
north and one south, would help a lot of people.
Have Fun!
Reg
On Monday, December 18, 2023 at 05:27:30 PM CST, Tom Gardner
<tggzzz@...> wrote:
[snip]
I wonder if there is scope for a big meeting somewhere central,
rather than trusting items to the post?
|
We've wondered before about getting some standards (hired or borrowed) at EMF Camp
The thought from the camp organisers was that hiring wouldn't be justified by the usage (and tbh, a camping event isn't the best place to compare precision standards!) but I think they'd do their best to support a meeting if it wasn't unreasonably expensive.?
Better still might be to ask NPL at one of their regular open days to provide access to some high-end? equipment but they might be wary of creating something that might be swamped by some fringe trade sellers.
The BATC (amateur TV) group used to get an array of expensive RF test gear at their annual conference but I don't know if they still do that.? ?
I do think that although individually we might have only one or two useful instruments, when working together we could put up quite an array. I'm not at all sure what sort of precision we could get to though with perhaps poor climate control and limited time for settling and careful testing.
On Mon, Dec 18, 2023 at 11:50?PM Reginald Beardsley via <pulaskite= [email protected]> wrote: Tom et al, May I suggest to arrange a meeting room at a restaurant or hotel for a day once a year and everyone bring their cal standards. With a strong turnout, NPL might do the honors. Such an event is impossible (at least for me) in the US because of distance, but in the UK a pair of such weekend events, one north and one south, would help a lot of people. Have Fun! Reg On Monday, December 18, 2023 at 05:27:30 PM CST, Tom Gardner < tggzzz@...> wrote: [snip] I wonder if there is scope for a big meeting somewhere central, rather than trusting items to the post?
|
Tom et al,
May I suggest to arrange a meeting room at a restaurant or hotel for a day once a year and everyone bring their cal standards. With a strong turnout, NPL might do the honors.
Such an event is impossible (at least for me) in the US because of distance, but in the UK a pair of such weekend events, one north and one south, would help a lot of people.
Have Fun!
Reg
On Monday, December 18, 2023 at 05:27:30 PM CST, Tom Gardner <tggzzz@...> wrote:
[snip]
I wonder if there is scope for a big meeting somewhere central, rather than trusting items to the post?
|
May I suggest ordering some of these from JCLPCB?
https://oshpark.com/shared_projects/PzvtIxv4
I have 3x of these:
https://oshpark.com/shared_projects/DMMaC4j1
which Jason sent me. I also have 10x more used LM399s for which I'll use the first cited design. The 3x basic LM399s and 3x AD584s are mounted awaiting a decision on where to put 3x LM317s for the cleanest wiring to the 4492A on my 3457A for long term data collection.
You've inspired another thread.
Have Fun!
Reg On Monday, December 18, 2023 at 04:46:56 PM CST, Adrian Godwin <artgodwin@...> wrote:
On Mon, Dec 18, 2023 at 9:55?PM Chris Hayes < krizhz@...> wrote: Hi Adrian, good to hear from you... especially as you are local. Maybe we need to start with a portable Voltage Standard. I made a 5 Volt ref in a box some time back but have not checked it's tempco yet. It is about 20mm thick, so it might go as a large letter.?
Sounds interesting. I have a few LM399s but not done the work to make a transfer standard. But it would be very good to get a UK cal group together, for both DC and the stuff Reg is talking about. ?
Does your HP53310A use the vanishing carrier technique? I used to enjoy doing that manually while working at Cossor Electronics in Harlow.
No, it's a very high speed counter that measures the carrier frequency at modulation speed (and then displays a graph of frequency against time with min/max measurements). So it's an absolute measurement of frequency change rather than a calibrated demodulator (or, I guess, a mathematical technique as I imagine the vanishing carrier to be).
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On Monday 18 December 2023, Adrian Godwin < artgodwin@...> wrote: > On Mon, Dec 18, 2023 at 9:55?PM Chris Hayes < krizhz@...> wrote: >> >> Hi Adrian, good to hear from you... especially as you are local. >> Maybe we need to start with a portable Voltage Standard. I made a 5 Volt ref in a box some time back but have not checked it's tempco yet. It is about 20mm thick, so it might go as a large letter.? > > Sounds interesting. I have a few LM399s but not done the work to make a transfer standard. But it would be very good to get a UK cal group together, for both DC and the stuff Reg is talking about. > ? >> >> Does your HP53310A use the vanishing carrier technique? I used to enjoy doing that manually while working at Cossor Electronics in Harlow. > > No, it's a very high speed counter that measures the carrier frequency at modulation speed (and then displays a graph of frequency against time with min/max measurements). So it's an absolute measurement of frequency change rather than a calibrated demodulator (or, I guess, a mathematical technique as I imagine the vanishing carrier to be). > The Time Interval Analyser has other tricks up its sleeve, e.g. measuring subnanosecond risetimes. In Brizzle, I have a small selection of resistance standards that are meant to be in oil baths, a couple of Sullivan mica capacitors, a well aged Trancell II transfer voltage reference, a Cropico voltage standard, an in-spec Weston standard cell thermometer (sic), a Julie Labs 7decade KVD. I wonder if there is scope for a big meeting somewhere central, rather than trusting items to the post?
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Dr. David Kirkby, Kirkby Microwave Ltd
bownes