The AM Forum
October 10, 2024, 01:15:45 AM *
Welcome, Guest. Please login or register.

Login with username, password and session length
 
   Home   Help Calendar Links Staff List Gallery Login Register  
Pages: [1]   Go Down
  Print  
Author Topic: LC Meter/Bridge  (Read 4496 times)
0 Members and 1 Guest are viewing this topic.
w9jsw
Two shots of Whisky
Contributing
Member
*
Offline Offline

Posts: 599



« on: January 13, 2023, 08:02:08 AM »

What are you folks using for an _accurate_ LC meter. I am working on tank coil values and suspect that my inexpensive hobby LC100 unit is not accurate at low inductance values. What is a good choice for accurate uH measuring that is reasonable cost?

John
Logged
KA3EKH
Member

Offline Offline

Posts: 792



WWW
« Reply #1 on: January 13, 2023, 09:02:32 AM »

I have a huge General Radio 650 Impedance bridge that I picked up for $20, it got to be at least fifty or sixty years old if not older but with the internal 1 Kc oscillator and just a pair of headphones you can get real good readings on the impedance of chokes and transformers. Don’t know what the highest usable frequency would be using external excitation and an external detector but can see it working up to 10 or 12 Mc without issue. Also allows you to do real accurate DC resistances, like out to a decimal point on low value resistances.
Think the trick is to start out and learn how to use it working with items of know quantity and then you can progress to unknown values. The huge size and Walnut case along with the overall look of something from the nineteen thirties were a plus for me, but in this world of everyone wanting micro size Chinese junk can see where that may not appeal to everyone.
Logged
W1ITT
Member

Offline Offline

Posts: 580


« Reply #2 on: January 13, 2023, 09:49:12 AM »

John..  Keep on the lookout for an AADE LC meter.  Almost All Digital Equipment was a one-man shop and is out of business now.  Neil is SK.  His LC meter is handy, palm sized and self contained.  You can zero out fixtures on both the L and C ranges so as to measure just the component and not the strays.  I have taken mine all over the world to do the initial setup on phased arrays and it saves time and stress.    I think they cost about $100 a decade or so ago. 
73 de Norm W1ITT
Logged
KD1SH
Member

Offline Offline

Posts: 853



« Reply #3 on: January 13, 2023, 10:03:48 AM »

This has been my go-to for a few years now: https://www.deree.com.tw/de-5000-lcr-meter.html
I have no calibrated laboratory gear to compare it to, but it seems accurate and provides a lot of information.
Logged

"Gosh, Batman, I never knew there were no punctuation marks in alphabet soup!"
—Robin, in the 1960's Batman TV series.
w9jsw
Two shots of Whisky
Contributing
Member
*
Offline Offline

Posts: 599



« Reply #4 on: January 13, 2023, 10:19:49 AM »

Wondering if I should be looking for an Autek RF-1 so I can check the tank L at frequency, as well as do all sorts of antenna experiments?

The DE-5000 also has my eye. How accurate does it seem to be when extrapolating the inductance at measurement vs. a coil at 1.9MHz for instance?

Does the Q feature bring more to the party? I have been using SimSmith lately and being able to measure inductance and Q would be quite useful.

John
Logged
KD1SH
Member

Offline Offline

Posts: 853



« Reply #5 on: January 13, 2023, 10:46:55 AM »

I've used it to read the inductance and Q of brand-new 1% tolerance small value inductors, and it seems very accurate. I've also compared its readings to my own extrapolated predictions arrived at by various methods including sweeping with my RF generator and using a grid dip meter, and it all seems right on. I'm sure it's not the equivalent of a kilo-buck lab instrument, but my use it's fantastic.

Wondering if I should be looking for an Autek RF-1 so I can check the tank L at frequency, as well as do all sorts of antenna experiments?

The DE-5000 also has my eye. How accurate does it seem to be when extrapolating the inductance at measurement vs. a coil at 1.9MHz for instance?

Does the Q feature bring more to the party? I have been using SimSmith lately and being able to measure inductance and Q would be quite useful.

John
Logged

"Gosh, Batman, I never knew there were no punctuation marks in alphabet soup!"
—Robin, in the 1960's Batman TV series.
Carl WA1KPD
Contributing
Member
*
Offline Offline

Posts: 1648



« Reply #6 on: January 13, 2023, 03:03:26 PM »

John..  Keep on the lookout for an AADE LC meter.  Almost All Digital Equipment was a one-man shop and is out of business now.  Neil is SK.  His LC meter is handy, palm sized and self contained.  You can zero out fixtures on both the L and C ranges so as to measure just the component and not the strays.  I have taken mine all over the world to do the initial setup on phased arrays and it saves time and stress.    I think they cost about $100 a decade or so ago. 
73 de Norm W1ITT


I love mine and am sorry they are no longer available.
But in doing some BC work I discovered it will not measure coils that large.

Not a deal killer, to me,  just something to be aware.
Logged

Carl

"Okay, gang are you ready to play radio? Are you ready to shuffle off the mortal coil of mediocrity? I am if you are." Shepherd
km6sn
Contributing
Member
*
Offline Offline

Posts: 91


« Reply #7 on: January 13, 2023, 08:56:26 PM »

Best LC meter I ever had is homebrew, measuring to 1%, from this article
https://www.qsl.net/wm5z/cq199301b.pdf

I wrote arduino code to do the calcs and display, and calibration.\
email me at  km6sn@fastmail.com for the code.

The configuration is simple:  a 74AC74 doing a divide-by-4 prescaler,
a 16 MHz arduino, and the human interface is via the serial port on the arduino.

The 74AC74 was mounted dead-bug, with a s/m 100n bypass right at the power pin.
 Be aware that the 74AC74 clock input  will trigger on analog signals, so no A/D is required. I probably biased the input clock line to vcc/2 .

The whole thing, arduino and  all, mounted on perfboard with a ground plane.

I used an Arduino Uno R3, which has a USB-B (large) connector for the serial port. I mounted the Arduino  so the USB connector stuck out  from a hole in
the chassis for ease of serial connection.

Then a USB serial board (FTDI) at the laptop end.


GL,

Rod
Logged
WA4WAX
Member

Offline Offline

Posts: 426


« Reply #8 on: January 14, 2023, 09:33:53 AM »

I have a DE-6000 and love it.  It is out of production and a bit hard to find.  DE-5000 is fairly easy to find, and just as good for most applications.

I have an All Digital L/C meter and will sell it. It is like new.
Logged
K9MB
Member

Offline Offline

Posts: 361


« Reply #9 on: January 14, 2023, 10:36:35 AM »

What are you folks using for an _accurate_ LC meter. I am working on tank coil values and suspect that my inexpensive hobby LC100 unit is not accurate at low inductance values. What is a good choice for accurate uH measuring that is reasonable cost?

John

John,
I have several meters and my favorite is the Tenma 73-960
Excellent range and good accuracy.

https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2380057.m570.l1313&_nkw=tenma+72-960&_sacat=0



https://datasheet.octopart.com/72-960-Tenma-datasheet-20064.pdf

Here are several for sale on Ebay used.

I also like my M4070 for smaller inductors
The 4070 and the Tenma give very close results in uH ranges.
Tenma better to measure big reactors and chokes and mod tranny windings.

https://www.amazon.com/s?k=M4070+lcr+meter&crid=3D3QH8SVL094R&sprefix=m4070+lcr+meter%2Caps%2C110&ref=nb_sb_noss

73, Mike
Logged
WU2D
Contributing
Member
*
Offline Offline

Posts: 1797


CW is just a narrower version of AM


« Reply #10 on: January 21, 2023, 09:34:37 PM »

I use the Boonton 160A. It gives Q and measures L and C and works great right where we need it in the HF band.

I also have a Boonton 250 RX Meter that would work as well, but the 160 is so fast and its the balls for seeing what happens to Q at specific frequencies.
Logged

These are the good old days of AM
w9jsw
Two shots of Whisky
Contributing
Member
*
Offline Offline

Posts: 599



« Reply #11 on: January 22, 2023, 07:02:21 AM »

Is anyone familiar with the B&K offerings? 2 of them offer ESR capabilities.

https://www.mouser.com/datasheet/2/43/87xB_datasheet-2487040.pdf

John
Logged
w9jsw
Two shots of Whisky
Contributing
Member
*
Offline Offline

Posts: 599



« Reply #12 on: January 22, 2023, 09:35:52 AM »

I use the Boonton 160A. It gives Q and measures L and C and works great right where we need it in the HF band.

I also have a Boonton 250 RX Meter that would work as well, but the 160 is so fast and its the balls for seeing what happens to Q at specific frequencies.

A good video of the unit. This is something I will look for at the hamfests.

https://www.youtube.com/watch?v=L2005LTmE7Q
Logged
WD5JKO
Member

Offline Offline

Posts: 2000


WD5JKO


« Reply #13 on: January 22, 2023, 12:41:56 PM »

Wondering if I should be looking for an Autek RF-1 so I can check the tank L at frequency, as well as do all sorts of antenna experiments?

Hi John,

  I have an RF-1, and for me it is a keeper. Sure, it is old now, low end, and suffered from build quality issues. Mine needed many connections within resoldered, or soldered for the first time!
I saw one on Ebay yesterday for $80.

   Whatever you use, the connection to the device under test is where a lot of the the inaccuracies come from. Some have a calibration kit, to take out lead-length with an "open", "short", and "50 Ohm" standard. With something like an RF-1, that option does not exist, so you must measure at the connector (SO-239) with minimal lead length. The RF-1 does measure at the frequency of interest between 160-10m, a big advantage. It is quite useful measuring low value capacitors, like 47pf, or to measure the series resonance of a 0.01uf cap versus lead length (usually around 7-9 Mhz). I recently wound some toroids using mine, and the measurements closely matched the coil calculations.

   As the frequency of interest goes up, those LCR boxes using a fixed low frequency test signal become pretty darn inaccurate.

Good luck with your search!

Jim
Wd5JKO



Logged
DMOD
AC0OB - A Place where Thermionic Emitters Rule!
Contributing
Member
*
Offline Offline

Posts: 1805


« Reply #14 on: January 25, 2023, 07:01:27 PM »

Is anyone familiar with the B&K offerings? 2 of them offer ESR capabilities.

https://www.mouser.com/datasheet/2/43/87xB_datasheet-2487040.pdf

John

I have an older B&K, have had it for 11 years, it is very accurate, and has never failed.

Phil
Logged

Charlie Eppes: Dad would be so happy if we married a doctor.
Don Eppes: Yeah, well, Dad would be happy if I married someone with a pulse.NUMB3RS   Smiley
MikeKE0ZUinkcmo
Member

Offline Offline

Posts: 443



« Reply #15 on: January 26, 2023, 03:15:37 AM »

If you're interested in the Boonton, I would also suggest you look for the 260 as well.   A bit more modern and easier to use.  

 

Another Boonton meter thats handy for RF, is the 250 Rx meter.



Be sure to take a small coil of roughly known inductance, and the value of capacitance needed to resonate at your chosen test frequency, with you to test what ever bridge you may find.   The Boonton's often have blown thermocouples because of misadjustment during the testing process by those that won't or can't read manuals, making them useless.  To that end, I'd recommend a quick read of the manual beforehand to familiarize yourself with the meter.

These old guys are slow to use, but accurate.
Logged

Mike KE0ZU

Bold Text and PICS are usually links

https://mikeharrison.smugmug.com/
Pages: [1]   Go Up
  Print  
 
Jump to:  

AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
 AMfone © 2001-2015
Powered by SMF 1.1.21 | SMF © 2015, Simple Machines
Page created in 0.048 seconds with 19 queries.