[Amps] measuring rf colis

[m.ford]

      Gee, no mention of the Tektronics LC-130. I have a pair of them, one set up
with a C jig and the other for L.  We had an old Boonton with top terminals
at work that was great for small coils wound under a microscope. Nice smooth
metal plate under the terminals so you didn't have to sneak up on it to get a reading.

Mike k1ern



----- Original Message ----- 
From: "Will Matney" <craxd1 at verizon.net>
To: <amps at contesting.com>
Sent: Tuesday, January 24, 2006 9:42 PM
Subject: Re: [Amps] measuring rf colis


Conrad,

I spoke to the designer of this LCR meter a while back about converting the kit to a bench meter and decided against it.
The reason for me was that the components needed to be mounted as close to the test terminals as possible and it didn't
use the shielded lead method. However, for a handheld LCR meter, he did a very good job and it's better than the B&K
handhelds that were made in accuracy.

I have three LCR meters here I use, a Leader LCR-740 analog type, a GenRad Digi-bridge 1657, and an ESI 251. The Leader
is OK, but needs the components right at the terminals to be measured correctly. The GenRad is almost like it as it
doesn't have the shilded leads per say, and you use clamp terminals on top of the meter. They do make a set of leads
which plug into the terminal strip something similar to the digital Heathkit LCR meter. The ESI uses Bananna jacks but
come into a shielded lead steup (Like some HP). I have actually had a low inductance tank coil in my hand while
measuring it and squeezing the coil to change its inductance while watching on the ESI 251. It stays the same whether I
was handling it or not which surprised the dickens out of me. I did a bunch of research on these when I started building
up for a transformer and coil shop.

Anyhow for the price, if I wanted to measure a few coils or caps here and there, the one you mention is a decent meter
and there is some imports which aren't too shabby. Below is some links on eBay for a few.

Leader LCR -740;

http://cgi.ebay.com/LEADER-LCR-740-Inductance-Capacitance-Impedence-Bridge_W0QQitemZ7583877861QQcategoryZ25421QQrdZ1QQcmdZViewItem

L/C Meter IIB Unbuilt kit (one in mention);

http://cgi.ebay.com/Inductance-Capacitance-meter-L-C-Meter-IIB-Unbuilt-kit_W0QQitemZ7584423880QQcategoryZ25421QQrdZ1QQcmdZViewItem

BK Precision 875A;

http://cgi.ebay.com/BK-Precision-875A-LCR-meter_W0QQitemZ7584290546QQcategoryZ25421QQrdZ1QQcmdZViewItem

DIGITAL LCR;

http://cgi.ebay.com/DIGITAL-LCR-METER-MULTIMETER-TEMPERATURE-NEW_W0QQitemZ7583602075QQcategoryZ25421QQrdZ1QQcmdZViewItem

LCR Meter,Capacitance/Inductance, AC/DC V/A/R/Hz/T, NIB; (My favorite)

http://cgi.ebay.com/LCR-Meter-Capacitance-Inductance-AC-DC-V-A-R-Hz-T-NIB_W0QQitemZ7583295805QQcategoryZ25421QQrdZ1QQcmdZViewItem

GenRad 1656;

http://cgi.ebay.com/GR-1656-Impedance-Bridge_W0QQitemZ7582746915QQcategoryZ25421QQrdZ1QQcmdZViewItem

ESI 250DE;

http://cgi.ebay.com/ESI-250DE-LCR-Bridge-Impedance-Capacitance-Inductance_W0QQitemZ7584146904QQcategoryZ25421QQrdZ1QQcmdZViewItem

 ZM11/U Military;

http://cgi.ebay.com/ZM11-U-CAPACITANCE-INDUCTANCE-RESISTANCE-BRIDGE-VINTAGE_W0QQitemZ7584725342QQcategoryZ25421QQrdZ1QQcmdZViewItem

Best,

Will



*********** REPLY SEPARATOR  ***********

On 1/25/06 at 2:15 AM Conrad_G0RUZ wrote:

>Don't MFJ recommend putting a known value capacitor in parallel with the
>coil and measuring the resonance? Then as you know the capacitors value ±
>5%
>and the MFJ frequency ± 5% you should be able to calculate the approximate
>inductance of the coil for large inductors at lower frequencies at least.
>Forget it in the VHF region though, stray C between turns become very
>significant. I use an AADE LC Meter II and I am delighted with it, it comes
>up with very accurate results on some lab standard inductors that we have
>at
>University. Here is a link
>http://www.aade.com/lcmeter.htm
>
>73
>
>Conrad G0RUZ
>
>> -----Original Message-----
>> From: amps-bounces at contesting.com
>> [mailto:amps-bounces at contesting.com] On Behalf Of Will Matney
>> Sent: 25 January 2006 01:47
>> To: amps at contesting.com
>> Subject: Re: [Amps] measuring rf colis
>>
>> Chuck,
>>
>> Most stock chokes are measured at frequencies around 1 and 10
>> kHz using a precision LCR (bridge) meter. I have both the
>> analog and digital bridges here and use both. There are some
>> LCR meters by HP and a few others which can measure up to 10
>> MHz. Most all stock coils though like Ohmite are measured at
>> around 1 to 10 kHz. The three top manufacturers of LCR meters
>> is HP, ESI, and GenRad.
>>
>> Best,
>>
>> Will
>>
>> *********** REPLY SEPARATOR  ***********
>>
>> On 1/24/06 at 7:51 PM Partain, Chuck wrote:
>>
>> >probably touched upon 10k times but..
>> >
>> >Using my MFJ-259b, measuring some rf coils I have here, sweep the
>> >frequency...
>> >all coils I have, move all over the place. Is there a standard
>> >frequency these are rated at?
>> >
>> >say a coil is advertised at 10uh. at what frequency? I can
>> pretty much
>> >determine the current by the size of the wire...??
>> >
>> >chuck
>> >_______________________________________________