I?just?received?one?of?Leo?Bodnar's?new?LBE-1322?pulsers.??I?measured?19?ps?rise?time?for?the?1322?vs?15?ps?for?the?11801?calibrator?and?the?two?pulsers?in?my?SD-24?using?an?11801?and?40?GHz?SD-32?sampling?head?fed?through?a?2.92?to?3.5?adapter.??That?is?superb.??There?are?very?few?circuits?with?that?performance.??And?none?are?as?cheap.??Leo's?pulsers?are?a?steal.??I'm?one?of?those?who?requested?external?trigger?from?a?GPSDO.

Unfortunately,?fast?sampling?scopes?are?a?disappearing?item.??However,?Leo's?product?makes?building?a?low?cost,??functional?equivalent?of?an?11800?mainframe?&?SD-24?viable.??The?really?hard?part?is?that?step?response.?Leo's?done?that.

Based?on?list?price?for?the?existing?bits?I?think?that?a?20?GHz?single?channel?TDR?for?<$1000?is?economically?practical,?mostly?based?on?existing?COTS?products.??The?sampler?is?the?missing?piece.

If?you?have?not?used?20?GHz??level?TDR?for?connector?and?cable?testing,?you?cannot?imagine?how?useful?it?it.??It?will?catch?intermittents?that?sweeping?misses.??It?will?also?show?you?if?it's?the?connector?or?the?cable?crimp!??No??way?to?see?that?in?the?frequency?domain.

I?think?that?Leo?Bodnar?has?demonstrated?that?there?is?huge?potential?in?low?cost?<mm?TDR. Happy to work with anyone who wants to poke at the beast.

Have Fun!
Reg

I've noticed that the enclosure of my HP 4342A Q meter can seriously degrade the Q of a physically large coil. I wrote a Windows program that lets you extend the meter terminals with a parallel wire transmission line. You suspend the coil a foot or more above the enclosure, run parallel wires to the meter terminals, and record Q and capacitance. The program solves the telegraphers equation and provides the coil inductance and Q as if no transmission line were present. It uses the Getsinger equations to account for transmission line end-effects. Results for a small coil with no enclosure interaction with and without terminal extension were very close.

The program is part of the Q meter utilities listed in the middle of the following page. Another utility compensates for the Q of an auxiliary capacitor used to extend Q meter range. It calculates the Q the meter would indicate if the auxiliary capacitor had no loss. See the end of the page for downloading instructions.



Brian

Referenced paper does not include resistive core loss, therefor, incomplete.

See
"Real transformer equivalent circuit" which includes magnetizing branch.

Previous SimNEC model includes ferrite core loss, magnetizing branch,
and demonstrates your measurements are as expected.

John KN5L

Not too far off from expected, see attached SimNEC model for 73
material, 60uH primary, 1:1 transformer,

John KN5L

/me finds two files, but they appear to be in German, so they may (or
not) be of limited use...

On Tue, Sep 24, 2024 at 7:30?AM Marcelo - LU2DR via groups.io
<lu2dr@...> wrote:

Hello good morning. I have a Philips PM6301 LCR meter that I need to review.
I need if someone could send me the circuit and/or the service manual or
alignment procedure.

Thank you so much.

73, Marcelo - LU2DR

Do you mean the 190 and 260?
Follow the instruction manual to turn on. The power switch is on the Q multiplier knob. Turn it just past the turn on point and allow the meter to warm up for a few minutes. You must have a coil connected to the coil terminals on top of the meter to get an indication on the Q multiplier meter. Connect the coil and check for zero reading. Then bring the Q multiplier knob up slowly until you get a reading. If you get a reading the thermocouple is OK. Set the meter for ! and adjust the frequency for resonance on the second meter, which indicates Q. You will need at least one standard Q coil. The meter should indicate close to the marking on the standard coil. It will have calibrations at three frequencies. The adjustment procedure requires a fairly accurate AC VTVM. The oscillator has a single frequency adjustment for all bands.
Note that the power supply uses a constant voltage transformer. These can go bad, the usual symptom is that it runs very hot. They run hot normally but can get hot enough to melt the potting material. If bad must be replaced, have to get one from a junker meter. For the most part they are quite reliable.
Note that the Q multiplier meter and thermocouple were supplied as a pair, the calibration of the meter depends on the characteristics of the meter. In general it is the older version of the Q-Meter, 160-A that is the delicate one. The 260-A can be burnt out but its rare.
Keep the coarse Q control at zero when changing bands and you won't have trouble.
Note that Q was sort of invented by Boonton. The NBS would never certify Q standards because they considered them indefinite. However, if your meter is working correctly it should give you the Q and capacitance values on the standard coils pretty closely. Make sure the frequency is set accurately, use a counter.
I have a couple of 190-A, the VHF version of the meter. AFAIK the thermocouples in them are quite rugged. Boonton made standrd coils for them but they are quite rare.
Note: Boonton made both "standard" and "working" coils. The standard coils are the ones for checking calibration. The working coils mostly have higher Q than the standards and are useful for measuring capacitors etc when you want a coil of known inductance without having to wind them.
Q-Meters are sort of forgotten instruments. IMO they are still very useful but few even know what they are.
Boonton was bought by Hewlett-Packard and the HP History site has manuals and the Boonton Notebook along with various service notes, etc. There have been a couple of replacement designs for the special tube used as the electronic voltmeter. I have one but it throws the calibration of the meter off. I have a note somewhere on what the generic tube was but they were selected and its hard to find replacements. For the most part they have extremely long lives.
Do NOT bend the plates on the main capacitor. The trimmer cap can be adjusted slightly to bring the vernier cap into calibration, again, should be calibrated using a standard coil.
Read everything available, lots of little secrets buried in the literature.

--
Richard Knoppow
Los Angeles
WB6KBL
SKCC 19998

I acquired some 100kΩ 1.6mm glass bead thermistors of the type used in 3D printers for a flow soldering project, but the manufacturer’s characteristics were not available. ?0°C and 100°C temperatures are fairly easily established at sea level with ice and water, but it would have been be messy to set up an oil bath or similar.?

A piece of 3.5mm aluminium bar approximately 23 x 15mm was drilled in two places approximately 5mm apart on the narrow edge to a depth of 15mm as pockets for the thermistor and a type K thermocouple and held by a “third hand” clip by the wires so that hot air from a de-soldering tool could be applied safely.? The thermal mass of the bar was sufficient to allow the temperature and corresponding resistance to be measured repeatably.? The bar was heated to a number of temperatures at 20 degree intervals as indicated by the thermocouple and the resistance recorded.? On plotting out and comparison with a number of Arduino library results [1] the thermistor was found to be very close to the Type 1 characteristic.

Measurement accuracy is maybe 1-2% at 200°C, good enough for my purposes, and may be useful to others.

PeterS? G8EZE

?

[1] ?? ???? The tables are expressed as counts scaled 0-1023 on a 5V ADC

Well, looking at the schematic, if you get a reading on the multiply by Q meter, it would seem good. If you don't get a reading on that meter, it is not necessarily bad, it could be missing a drive signal. Schematic below to show the simple thermocouple circuit
? There is also a write up here,
It has a line, "A quick check of the heater/thermocouple assy (aluminum block under the gold plated terminals) is to measure from the BNC connector center pin to the LOW terminal, if that's open the heater/thermocouple is bad. If it's OK, measure from the LOW terminal to Ground with an AC RMS millivoltmeter (HP 3400, RCA WV-74A, Heathkit AC Voltmeter, etc). Use an oscillator frequency the voltmeter will handle (1-5Mhz for the good RF millivoltmeters, 500Khz or less for the audio millivoltmeters). The LOW terminal should measure 20mV when the XQ meter is at "X1" (1.0Amp into a .02 ohm resistor provides 20mv for reference). "

开云体育

I have had the above Qmeters for some time, which I have not attempted to use. Is there a way to test the thermocouples to see if these units are worth trying to restore?
Your attention is appreciated.
Ray, W4BYG

-- 
"If you want to build a strong house, I'll give you my engineer's number. 
 If you want to build a strong life, I'll introduce you to my carpenter."
  Lebron and Heather Lackey