What some of my customers have to say.
edited to protect personal information about my customers unless they gave permission.
Bernd in Portugal put a DFD2-Heath in his SB-102. Very professional looking.
HI NEIL ....I AM 73 THIS YEAR AN ON FIXED RETIREMENT FUNDS SO THAT IS
THE REASON FOR THE PCB BOX...I PUT SOME NEW CAPS IN THE OLD GIRL FROM
K4EAA'S SITE...AN GOT SOME MATCHED GE 6146W'S FROM NEBRASKA
SURPLUS..BEST PRICE I COULD FIND...~!.. I HAVE K4EAA'S DUMMY LOAD KIT
AN THE RIG MAKES 100 WATTS WITH NO PROBLEM....THANKS FOR A GREAT READ
OUT AT A FAIR PRICE....73...ED
Hi Neil,
Just wanted to say thank you for the LC meter that I purchased recently.
I have built a couple of these from scratch but was never happy with the
stability, and my attempts at packaging were miserable. I do a lot of
homebrewing, using often questionable components, so I use these
meters a lot.
Finally one of my homebrew efforts quit, so I decided to buy your meter.
Very good decision. Well worth the amount you are asking for it. Rock
solid measurements and a package that should last OK.
The kit was very easy and I thought the numerous pictures would be
helpful to anyone constructing it. The only place I recall being somewhat
unsure about was orienting the two IC sockets. You might also want to
give some tips about how to insert the uP into the socket (I find that bending
the pins slightly inward beforehand makes the process easier).
The only change I would suggest is a power socket and a diode so that
people could use the meter either portably or from AC power. Not a difficult
mod, of course.
I will have no hesitation recommending this LC meter to others.
73, ian
Neil,
Wow! What an exceptional unit the DFD1A turned out to be! I am building a prototype 4-tube
12 volt plate superheterodyne AM radio and I wanted a good digital display - this one is
amazing! It is both very accurate and very stable. I even used it to align and track the
tuning of the radio. Actually, I would have been hard-pressed to do the alignment without
the DFD1A. It is a pity that I did not order the device fully configured and mounted
within the metal case.
Thanks, and keep up the good work!
Bruce
Hi Neil:
Several years ago I purchased one of the meters and I must say it has
done an excellent job for me. When measuring inductors I've occasionally
noticed some odd effects and being as I'm currently building some BPFs
decided to document what's happening.
I've wound 11 turns of #24 on a T50-6 toroid to give a calculated
0.480uH. The meter has been powered on for ten minutes or so and should
be stable. This is the sequence I'm following:
1. Power off meter and connect test leads together. Leads about 4 inches
long.
2. Power on meter, when ready measure u appears press Lx. Inductance
reads 0.005uH. Zero the meter.
3. Connect toroid to the test leads, L measures 0.583uH. Toroid leads
about 1 inch long.
4. Leave toroid connected and power off the meter.
5. Power on the meter, when ready measure u appears press Lx. Meter
indicates 0.473uH.
I can repeat the above several times and the results are pretty much the
same.
What do you think is causing the discrepancy of 0.1uH or thereabouts
which is significantly more than the stray L appears to be, and more
importantly, which is the correct result?
73,
Brian
I tried your experiment using a .905 uHy standard inductor so I
can be sure of it’s true value.
1. Power off meter and connect test leads together. Leads about 4 inches
long.
2. Power on meter, when ready measure u appears press Lx. Inductance
reads 0.008uH. Zero the meter.
3. Connect inductor to the test leads, L measures 0.917uH.
4. Leave inductor connected and power off the meter.
5. Power on the meter, when ready measure u appears press Lx. Meter
indicates 0.757uH.
6. Power off meter and open circuit test leads. Leads about 4 inches
long.
7. Power on meter, when ready measure u appears, short test leads, press Lx. Inductance
reads 0.008uH. Zero the meter.
8. Connect inductor to the test leads, L measures 0.922uH.
Answer is:
component should NOT be connected when turning
meter on (during CALIBRATE)
open circuit or short circuit test leads makes little difference during power on.
Correct answer is by method 1-3 or 6-8 above as is described in the instructions.
Neil
Dear Neil,
Bought the L/C meter kit and put it together last nite. Only problem was finding pin 1 on
the PIC chip, there was no white dot near any pin so I guessed a big circle on the chip
was toward pin 1, The LM3111N had a clear white dot right at pin 1. So the display was
blank at power on and the 9V dropped to under 8V with probably over 100ma being drawn, and
I reveresed the chip and when I saw L/C Meter IIB come on the display all was well, and I
guess I was lucky I didn't blow the voltage regulator as you say in your directions!
My suggestion would be to say that if there isn't a white dot, use the indent on one end
of the chip as a guide and with it on the left pin 1 should be toward you as you typically
use for 8 and 16 pin dip's. I am just a hobbyist and worked as an electronic technician
through college at a TV shop and in industry in the 1980's and I am amazed that finding
pin 1 on chips can still be a challenge, even with all the modern micro laser printing
capabilities!
Your directions were outstanding, I have not built a real kit since Heathkit just before
they stop selling kits, as I have homebrewed some small accesories (rf current probe with
my own op amp circuit, etc.) and I was a little nervous building this kit. The only minor
thing not mentioned was to plug in the display unit before testing it, that should be
mentioned right after the step for plugging in the chips. Also my yellow 0.1 ufd C5,C6
caps had BC104K printed on them not 100n, but I knew they were right from elimination of
all other caps and I did check their value with my old Heathkit 2372 multimeter which has
a capacitor checker beforeI soldered them in.
And the cap measurments are so good! I have a shelf full of variable caps that I need to
re-check as my old Heathkit isn't too accuarate in the pf range. I check a 4 1/4"
piece of RG 213 coax that I had used in a tuner as a capacitor as the variable cap I had
in wouldn't go that low. My old Heathkit showed it about 8 pf, but with RG 213 being 30.8
pf/foot it should be about 4.25/12 x 30.8 or 10.9 pf and your meter showed between 10.6 to
10.9 pf, great! And I checked a couple torrids I used as RF transformers and saw what the
real inductance was, now things make more sense to me as when you don't have enough
inductive reactance the unbal to unbal bi-winding transformers won't work properly without
a lot of loss!
I did notice you should let it sit on 5 minutes or so to improve the accuracy and
stability.
So I highly recommend the unit to other hams. very innovative innexpensive unit you
designed for measuring pf caps and uH to 150 mH coils .
I have just a couple questions about the 9V battery. I measured about 8 ma draw once the
unit settled in (it peaked at 20 ma for a second when initializing.) Is that about right?
Also, what voltage range can be used? If voltage goes low, what will you notice, dim
display, unstability? Also, can you power it with 12 to 14 V or is that too much for the
LT1121CZ-5 5V regulator?
Again thanks for the great kit. I do strongly suggest you provide alternate guidance for
the computer chip in case there is no dot for pin 1. You don't want too many goofballs
like me plugging it in wrong!
73,
Jim
Just a note to thank you for a great product. Mine L/C meter went together in about an
hour and it worked fine the minute I hit the switch. The accuracy appears to be excellent.
For the money, I think it’s the best deal that’s come along in a long time.
And, by the way, the instructions were perfect.
Dave
Hi Neil,
I received my DFD1A a few days ago , and have now had the opportunity to set it up and
work with it. I am very pleased with it. I am using it with an Eddystone 680X . It was
already set up for the Eddystone’s 450 KHz IF , and I am taking the input from the
frequency changer . At first I was a bit concerned that the interface probe was not
included, as on your website, the page for C-DFD1A states at the top “Using the
universal interface (included), installation is almost plug-n-play”. But after a bit
of thought , I made my own tube shield interface by simply using stiff self supporting
enamelled coil winding wire with the tube as the former to wind a pickup coil of about 20
turns to connect to the DFD1A. It works fine.
Thanks for a fine product. Without intending in any way to detract from your efforts , I
have two suggestions for possible future upgrades :
1) Replace the RCA type connectors with DC type connectors for the power cable.
2) An option to reduce the display resolution to show the frequency to the nearest KHz
only.
Best Regards,
Eric
Neil. I built your frequency counter a couple of months ago and thought it was a very good value. Since then I bought an L/C meter from your competitor for $30 dollars less than your offering and you were right.
I should have spent the $99. Your L/C meter is better in every way. Included is a photo of both units packaged in aluminum boxes. Romeo
Hi Neil,
Must congratulate you on the quality of your meter. I am quite experienced building
projects and reading diagrams, but I am sure if I were not; building your instrument would
be a breeze.
All parts were there and no xtras. Congratulations. Something seemingly so simple is for
many too hard to do. It worked first go. Admittently I thought for a moment that I would
be the odd one out, having a problem as nothing showed up on the display initially, but a
quick play with the contrast solved the problem. Mine has to be completely clockwise and I
had it originally set to 80% or so, which was not enough to show anything while I expected
to see at least something, hence my initial thought it was not working.
Love the quality of your "Made in USA" case! Not many things are made in USA
anymore as you are loosing your manufacturing (is prosperity) base rapidly. Get rid of
your government!
I did come across a variety of clones and partial clones of your original design. Some
Ham's write their own programs in different pic's. Yours is well priced and of undisputed
quality. I like it you use the 311 instead of a comparator in pic because when people make
mistake (I guess) by having charge on capacitor, it won't destroy the pic. Also the 8Mhz
clock makes it "on the fly" adjusting.
I took a high quality 1 uF cap from the bench not realizing that it might still have some
charge in it and it fried my 311. Thanks to the IC socket and your trouble shooting sheet
it took only a couple of minutes to repair. The program did not continue and got stuck on
the calibrating phase, so the oscillator had to be "dead"; and it was.
This project has raised my interest into the pic's and their abilities and I am looking
now into some other interesting projects using these chips.
Thanks for a very nice kit that does what it promises very conveniently. Now winding coils
is fun indeed.
Best regards,
Gerard (ZL3GVR)
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Neil herewith you some pic regarding the object.
If you like you can report in your web site.
I think i will purchase another one....
Ciao 73 de I2QEN Emilio
How Emilio packaged his DFD2 with built in power supply.
I have an Omni C display with such a chip in it. I have no idea if the chip is
any good. My display would go flaky after heating up a bit. Ten Tec
techs assured me I had a cracked trace someplace and I run a solder bead along ALL display
traces several times and everything would *maybe* be good
for a while but the problem always returned.
The chips are available from obsolete chip jobbers but the price is *VERY* high and they
do not care to sell less that 100 at a time.
Eventually, I gave up and transplanted a DFD-1 in it for about $60. http://www.aade.com
Neil, the owner was very helpful in recommending the proper display. I now have two
of them.
And for what it is worth, when I did have some difficulty with one display, Neil's
service and support were
fantastic. I like being treated well and subsequently bought another AADE display in
the external box kit
for my HW-9.
The Omni C is no longer "original equipment" but the display works well and it
looks great.
Carl
Hi Neil
Just connected up your digital display.
Works first go.
Only a small loading of the tuned circuit, the universal interface
should fix that.
Thanks for making the display, it has made finding stations a whole
lot easier.
Find attached photos of the installation. ( C-DFD1A )
The extra DPDT switch is the first photo,
turns the whole unit off
and isolates the IF cable coming into the counter.
In the second photo, The grey matches the radio gray. The display
it not lit and is very readable in daylight, nice and contrasty.
Works real nice. thanks again.
I will be in touch soon for an other kit.
Regards John, Mudgee Australia
Neil - It's taken ages to complete my project but it's now up and running
http://ukradio.info/OIRT_Tuner/
I have included a link to your home page
- Julian
OK, I did not know what a OIRT tuner was either so I looked it up on wikipedia
| In most of the world, the FM broadcast band, used for broadcasting FM radio stations, goes from 87.5 to 108.0 MHz. In Japan the FM broadcast band is 76–90 MHz, unlike any other country in the world. The OIRT band in Eastern Europe is 65.8–74 MHz (though a number of these countries have either added 87.5-108MHz and are operating the two FM bands simultaneously, as in the case of Russia, or have shut down stations on the OIRT band) |
Neil,
I bought one of these from you a few years ago. No complaints, in fact just the opposite.
I came across your information looking for something else, and I just thought I'd drop a
line to you to tell you it is easily one of the most useful tools I have ever owned (after
the 6-in-one screwdriver and the neon circuit tester.
As I'm sure you're aware, an electronics hobbyist tends to scrounge parts from old TVs,
radios - and sometimes even industrial equipment. Generally capacitors and resistors have
industry standard markings, but often chokes only have a manufacturer's part number.
The L/C Meter IIB resolves this and at a price that a hobbyist can afford. That little
device has paid for itself many times over.
I have a suggestion though. Might it be possible to design a similar meter that is capable
of measuring inductance to, say, 50 henries and capacitance to 1000 microfarads or
possibly more? I'm sure the component values would be quite different, but a "high
value" companion to the L/C Meter IIB would be extremely useful to me.
Again, I thank you, and I sincerely hope that the L/C Meter IIB has made good money for
you. You deserve it, it is a great product.
Bill
I usually recommend buying a cheap LCR meter on ebay for around $40 to measure the large values. Not very accurate for small values but adequate for larger values.
Neil
Many thanks for your helpful tips on the phone yesterday. I mulled it over a bit and tackled the job this morning. It was much simpler than I anticipated. Here's a photo of the unit in operation with my Hallicrafters S-20R Sky Champion
Many thanks for a well engineered accessory. It may well outlast the Hallicrafters S-20R!
Best Regards,
Lee
Hello Neil,
I was researching an L/C meter and unfortunately purchased one of the
DIY units. It was allegedly the $69.95 more accurate one. If my search engine
had hit your site first I would have bought a IIB right off.
Was lacking a resistor and never heard back from DIY. Bought some on Ebay and
finished the kit. I metered the resistors and checked the values and position.
Looked for shorts under magnification too. The meter came up on the display but
capacitance is totally inaccurate and the inductance portion always says "Out of
Range". Monkeyed around with it and into the trash it goes.
Ordered a IIb from Milestone built as I have too many kits I want to build and
desire to be able to measure the toroids to make sure I'm in the ballpark. Figured
if it's built and calibrated, I don't have to worry about it. If you want to use
this for promotion, be my guest. I sent a
review to eham that was courteous but I doubt they will print it.
Best regards,
Kurt
Neil i just ordered another kit from you for an ft 101 and here are some pics of the last one i installed if you like you can publish these pics on your website,Fantastic kit and i just love these ole 101's...Thanks and look foward to doing the next one..Howard
Thanks Neil for a great and fun project,Here are some photos of my second 101 and the dark blue display is very nice indeed..Use these photo's and my call for you site anytime ..Thanks for a great product and service
Hi Neil,
Looking forward to calibrating my DFD4 counter.
Nick
Brussels Belgium
Neil,
Finished your LC Meter yesterday, turned it on and it worked first
time. Your instructions were excellent and very detailed. The finished
product looks very professional. I am extremely happy with this meter
and hope to use it in many future "homebrew" Ham projects. The kit was
ordered on a Saturday morning and it arrived on Monday, much to my
surprise. Thanks for such a great product and service.
As I only just gained my Technician license just over a month ago I am
studying hard to take the General and hopefully the Extra class
licenses in the near future.
73
Terry
Neil,
here is a first look at the DDF2 installed in my "highly
modified"
Heathkit SB102.
The DDF2 works well in this application and it was so easy to build. Plus it
worked the first time I turned it on. Great product and very nice quality
too.
P.S. My SB102 has a front panel insert made by "Express Front Panels". I'm
still working on the mechanicals but its getting close...
Again thanks and 73s Fred
Neil,
I purchased an L/C Meter kit from you several months ago and, like everyone, I love it.
Even though it's not what I would call fragile, it is a unit that I want to take
good care of. Also, since my "bench" is an open table, it was hard to keep
it from collecting dust.
I had heard of a lady named Rose Kopp from the Elecraft Radio web site (they have a link
to Rose's site, which is just a group of photos at
http://www.smugmug.com/gallery/7058736_hZbo4/1/452236459_Bc3aF#452236459_Bc3aF ).
Rose
ElecraftCovers@rfwave.net
makes beautiful custom cases for all the Elecraft radios and they have a marvelous reputation among her Elecraft customers. I asked her if she would consider making a case for my L/C Meter. She made me a beautifully padded one that exceeded my expectations. It includes embroidery, pockets for test leads, etc.
Since I'm so happy with this case, and since I know the L/C Meter IIB is such a popular
tool, I wanted to pass this along in case you might be interested in mentioning these
cases on your site. I have no connection to Rose other than as a happy customer; I
stand to gain nothing here, but thought you might consider this a way to add even more
value to your customers without having to do anything but add the reference to your site.
In the case of Elecraft, they don't stock Rose's products; customers have to
contact her directly. I would think it could work the same way with you. I'd
be happy to provide photos if you'd like. In any case, thanks for reading this.
Mike
Camil Moujaber from Lebanon built this neat receiver and used a DFD1A to display the frequency.
Detail are on http://www.midcenturyradios.com/HM-Dual-11.html
Hi Neil,
I received the LC meter kit I ordered two weeks ago and since then I have put it to very
good use. I am building a small amplifier (20 W) and I have found the meter invaluable for
measuring the capacitance and more importantly, the inductance, of the low pass filter
components. It is really satisfying to design and construct the filters and have them work
as expected first time. Thank you for a very nice meter - a great addition to my
instruments.
73,
Allen
Neil,
I want to thank you for making such a high quality instrument available for a reasonable
price.
I bought the kit from you a couple of months ago and have been meaning to write for quite
awhile. Sorry it took me so long.
Anyhow, I am really impressed with it. Very easy to assemble and it works so well. I had a
couple of 1% inductors and a couple 1% capacitors, on hand in my salvaged box, and I found
the meter to be more accurate than they are. What can I say except this is a great
product.
Thank you,
Don
Neil,
I just wanted to thank you for the superb kit I received.
Confortably assembled in less than 2 hours, not a single glitch with the perfect
step by step instructions, worked right off at power-on.
L and C measurements very accurate too,
with the reference components I had on hands for checking.
Simple, rugged and reliable instrument, ideal for the amateur HF/VHF/UHF work, at an
affordable price.
And shipping was fast.
73 from F4GEQ
Jean-Luc Legoupil
Paris, France
Hi Neil,
I received my L/C Meter IIB kit this afternoon via Priority Mail. It took about 1.5
hours to assemble and it worked perfectly the first time. Your product is one of the
easiest kits that I've ever built....been building kits since my first Heathkit in the
early 60's. Thanks for providing such an affordable and useful piece of test
equipment. I will be using it extensively as I make my way through the construction
of many planned Softrock/Mobo projects. I can't imagine winding toroids or
identifying unknown SMD components without it.
Thanks again for a great kit and unbelievable service.
Best of 73s,
Bob
Hi mate
No support needed, just wanting to let you know that the display works perfectly with my
TS520S and the instructions were 100%. Well done on an excellent piece of engineering and
thank you for the extra packing of coax leads and rca power plug.
Top shelf mate, appreciate all the support, and will look out for another product that
suits asap!
Feel free to publish this, as you deserve all the credit.
Cheers
Grom vk6fgrm
Hello Neil,
I purchased the LCII Meter Kit last Wednesday
and I had it in my hands on
Friday. I assembled it over the weekend in about 2 hours. The assembly
process went well. It worked the first time I turned it on. The only difficulty I
had was inserting the 16 Pin LCD connector on the PC Board. Because the
connector was a little bowed I think this was the reason I had difficulty.
This is a great product and I am very pleased with its operation
and accuracy.
One question I have which I think is a normal occurrence is as
follows. When I push in the Lx switch it displays "Not An Inductor"
without any thing connected to the test jacks. I assume this
is normal?
I have also left my review of the LCIIB on the EHam.net website
as most of my use for the LCIIB will be for my Amateur Radio
Projects.
Thank You,
Vince
Hey Neil, Purchased the Drake frequency counter a few months back
and just wanted to tell ya what a GREAT piece of equipment you sold me. Sorry I waited so
long to post this but you deserve the big high five from me. I do have to tell ya that I
did a small mod to it cause the display was to bright when I turn the lights
off in the shack so I installed a dimmer in the back next to the three RCA
plugs. Thanks again for a great product. Feel free to post this.
"KC2EPD"
George
Pls find attached a pic of my RF measuring equipment (with his DFD4A frequency counter)
73! de Corneliu / YO4AUL
Neil:
I ordered the L/ C meter on Wednesday and got it in PA on Saturday. Wow.
It's really a nice looking unit - and - a high quality unit. Wow
I've been measuring every coil I have; sliding copper pipes, &
wire, & ferrite in & out them. Wow
The results match calculations and the time consuming parallel cap-
gdo-rcvr methods I've been using. Wow
Wow. What a great meter.
Fun stuff.
Capacitors are next :-)
Thank you Neil !!
Best Regards,
Dan
Hi Neil
A few weeks ago you kindly sent me a bezel for my previously purchased DFD1. Please find
attached some photos of the completed project.
The unit is built in the enclosure of an old parallel port switch box, which was just
perfect size wise.
I wanted to use the DFD1 with a homebrew single conversion superhet transceiver, this rig
has an IF of 10MHz and hence a VFO frequency of 4MHz. So that I could also use the DFD1 as
a straight frequency counter as well, I arranged a switch on the back panel so that either
function could be selcted easily. The offset 10 turn pots are now mounted on a small PCB
so that they can be adjusted without opening the enclosure.
The unit can be powered from either an external 12v supply or an internal 9v battery,
The backlight of the display is only enabled when connected to the external supply.
Its certainly more enjoyable to operated the homebrew rig and know where I am in the
band!!
Thanks again Neil, the DFD1 is a great design.
73 Steve
Hi Neil,
THANKS for the GREAT communication AND super fast ship!!!
I received my DFD2-520 on Thursday. Thought you might like to know it did NOT work right
away...BUT THANKS to the note you included with the manual - SURE ENOUGH after opening the
unit - the vertical board had pulled partially out of the socket from USPS abuse.
YES...you DID have the rubber band attached...BUT you could see the USPS box had taken a
hit. You may want to consider bubble wrap around the unit or something else to take the
shock.
ANYWAY - WORKS GREAT NOW !!! SO GOOD - I gave you a great write up on e-ham:
http://www.eham.net/reviews/detail/7425
THANKS for a GREAT PRODUCT
73
Ray
Hello Neil, just got my DFD2 Counter (C-520) Plugged it in
and it works Great!!! Thanks for the quick shipment and good condition in which it
was recieved.Plan to do business with you again.Seems to be just what I needed in the line
of a quality frequency counter.You can post this email on your website if you like as a
reference for your products.Thanks Again Sir!!!
73's - Brian
Neil, I just finished building the LC Meter kit and have to compliment you on it. I
received the kit while I was away on vacation and completed it this afternoon. It went
together nicely and appears to be an accurate device as I tested it against some known
values. It was quite a change from the DIY electronics kit I built that went together
poorly, operated about 1/2 hour and then died.
Best regards,73
Dennis
Hi,Just finished assembling my kit and it worked as soon as power was
applied, no problems whatsoever! I then proceeded to start measuring
various caps and coils on my workbench. The little meter is amazing!
It is dead on accurate as far as I can tell.
Thanks for a great little meter, something like this could only be
imagined when I fist started home-brewing ham equipment in the late 70s!
73
Glenn
We are in the middle of producing a prototype switching power supply that will be used
in EV’s.
A unit made by electronics-diy.com kept failing miserably and we decided to give you a
try.
If you can, put a sticker or some promotional material in the box so we can give you
credit on our myspace page and on the product itself.
Myspace link omitted to protect identity of customer
Thanks for offering a niche product!
Reuben
I received my L/C Meter IIB in the mail today. It went together easily and worked the
first time I powered it up. I immediately checked a 270 pf (2%) capacitor and a Tektronix
2.5 uHy inductor that I have used for years with my grid dip oscillator. The cap measured
268.1 pf and the inductor measured 2.504 uHy. I was impressed!
Thanks for a great kit with excellent assembly instructions. I'll recommend your L/C meter
to any one whose looking for such an instrument. I was also very pleased with the speed
that you got the kit to me: I ordered it on Tuesday (12/23) morning and received it in
today's (Saturday - 12/27) mail.
Thanks and 73, Barry
Hi Neil,
Just wanted to let you know that I put my Christmas gift together on Christmas day...
It was a quick, easy build of about 2 hours without half trying...
and it worked perfectly the first time I powered it up.
It's very attractive, simple and easy to use and surprisingly precise.
I've been lusting after the one belonging to my best friend down in Oklahoma and my wife
decided to give me a kit for Christmas.
No more of that connecting coils up to caps, grid dipping, and crunching numbers!!
Mike
Neil;
I received the IIB kit today and had it assembled and running in less
than 30 minutes.
This little jewel for $100 is worth $500, GREAT little device.
Thank you...
Neil,
I received my C-75 today and have it running on my KWM-2. I am very pleasantly surprised.
It works great, looks great and is very accurate! I would recommend it to any vintage
radio collector.
Thank you,
Lynn
One customer documented his construction of an L/C Meter IIB kit on his web site.
I hope you approve...
<http://www.kc5wa.net/aade/aade.html>
super piece of test equipment
RC
A very good L-C meter, easy to assemble and well supported by the manufacturer. If you
need a good, accurate L-C meter, this is the one to get. I am identifying several
inductors and the toroid units wound for the Softrock series of receivers.
A lot faster and easier to use than the General Radio 1650 and the Sencore LC meter and
other "VOM" type of meters.
By all means don't waste your money on the "Very Accurate LC Meter" sold by
"Electronics-DIY.com", which appers to be based on the same principle as this
one. They send a useless, un-drilled plastic box and once the kit is put together, the
consumption is in the order of 1/2 Ampere, which kills the LM-7805 regulator. No technical
support (sent 2 emails which they did not respond to) and there is no information on the
display in order to lower or disconnect the backlight. which is the culprit for the high
consumtion consumption.
Hi Niel,
Meter kit arrived today in good order and it's already working. It's a real pleasure
dealing with you and AADE as I know my order will be shipped out immediately and arrive in
the fastest possible time and I always end up with a professional looking product that
works every bit as good if not better than a commercially made item.
Thanks again for your great service
Lou
I have owned the meter for a couple of years. I really appreciate test equipment that
is accurate and reliable with repeatable measurements.
I have a good collection of test equipment. Your L/C meter exceeds all my expectations -
the best buy of any other equipment I own.
Many Tnx
Victor
Hello Neil,
I received my meter kit today & could not wait to start construction. When I did start
I was disappointed to find the enjoyment of putting it together was just too short..... I
had it working in just over 1 1/2 hours ! Works just as stated & I can see it will be
a great asset to my shack. I have recommended the kit as a club project to the secretary
of my radio club. If I might offer a couple of minor criticisms. My LCD display had minor
marking due to being rattled around in the packet with the other components in the bag. It
had worn through the protective plastic covering. This may only be a problem with
international customers. The other is that I found I had to provide support for the front
of the LCD display to prevent it pivoting forward on it's 16 pin mounting - a couple of
spacers made from composite material & a dob of neutral cure silicone on each are all
that was required.
Very nice job & well done. All at an excellent price.
Kind Regards, Peter
I mount the connector on the display at an angle of abut 100 to
110 degrees so that when it is plugged in it comes out parallel to the PCB. Connector has
some play in it. I will try to pack the display so it is not in contact with anything
onther than the plastic bag in the future.
Thands Peter.
Neil
PeterI finished the LC IIB this afternoon and it worked off the bat. I must say
that I'm very happy with it. I've drug home all kinds of meters, bridges and
things from hamfests and bought Chinese LC meters, but none of them have
worked very well or worked at all. I'm so happy to have something that's
accurate and that works!
John
Neil,
As you know this is the second meter purchased and they are absolutely fantastic! Also,
your fast shipping was appreciated as it was used yesterday afternoon just a few hours
after receiving it.
Thanks!
Alan
Feel free to add me to your list of satisfied customers. I bought the L/C Meter IIB kit
several years ago. I needed something to give me an approximation of components, for
example, an air variable cap. They are almost never marked. Coils marked with only a part
number. Nice - but useless to me. The only L/C meters I could see were lab grade, and
priced out of my range. Buying the kit was even more than I wanted to spend for something
I didn't see as all that good, but I bought it as I really didn't have much choice.
Neil, I have to say I was extremely impressed! I did not get an overpriced set of parts
and a schematic and a "Here, good luck!", which is what I really expected. I got
what has to be one of the biggest bargains in test equipment today. If someone cannot
handle the assembly manual as it is, they really should spend the $30 more and buy the
preassembled unit...but also should ask why would they be using this in the first place?
The accuracy and quality of this unit, for just under $100 in an easy-to-assemble kit, or
just under $130 pre-assembled is unbelivable.
Neil, I hope you can retire rich from this unit. I want to get a frequency counter
soon...they too have been out of my price range. Not any more!
Huggy Bear (Angel-In-Training)
Hello Neil! On the TS-520 SE, shorting the 1K resistor on the DFD2 HFO (R1) input
worked just fine for me to display correct frequency output on the 10M band. One other
note to save someone a little trial and error. The DFD2 BFO goes to the TS-520 SE CAR, VFO
goes to VFO and HFO goes to HET.
I have built these displays for a SB-102, a HW-101, two TS-520 SE's and used a DFD3 for a
TS-520. All have worked just perfect and are so stable. Thanks for such quality products.
Bucky, KB5DRZ
Hello Neil,
Thanks for another perfect match. Watch the styling uniformity with
1969 Telefunken ELK639 !
Great! Thanks for the exc. service..
Paul
Netherlands
Dear Neil,
I bought your LC meter I'm guessing about 3-4 years ago and I still love it. It is quite
the superior product for the price and quite possibly at almost any price. I go to
hamfests looking for old inductors and variable caps so I can build authentic looking
regenerative radios from the 20's and the 30's. It comes in super handy and I never fail
to tell folks how much I like it when I'm searching for old parts. Anyone who wants a
really nice product that's accurate AND portable should definitely give this a look.
Robert
I got the devices last week, had to add taxes when fetching them from custom, as I
knew. - I already made a few additions to the DFD4: 1) a few socket pins to easy coupling
of inputs, range and power; 2) a P-FET to prevent accidental voltage reversal; 3) 100k
resistor from pin 1 of MC12079 to ground. It's an old trick to prevent oscillation by
giving a 40 mV offset, sensitivity is degraded a bit. 4) Same thing for HC4046, 10k input
damping tames the IC. - Nice to use this circuit as an amplifier, I have used HC04U for
same purpose. I am also going to add preamplifiers both to HF and UHF.
Kindly: EePee
Dear Neil,
I received the LC Meter IIB 7 days after wining one on eBAY. Sensational considering I
live on the other side of the world. Australia is about as far as you can be
geographically from the USA. So thank you very much for being true to your word and
dispatching a very fine product.
It took me just over an hour to fully assemble the kit and it worked exactly as described
first time. It has a very professional finish - I only wish it had a protective case to
complement it. (I'll talk to my wife who loves to sew, and will hopefully have one soon) I
have been involved with electronics both professionally and as a hobbyist for over 30
years and I am thrilled with the meter. It now lives in the most special part of my house
- my shed (garage) along with all the other gear that keeps my busy late into many
evenings.
So congratulations on developing an invaluable piece of test equipment, and for offering
this has a high quality kit at a very reasonable price.
I wish you every success in your future endeavours.
Please feel free to add this glowing recommendation to your website.
Kindest regards,
Matt
Melbourne Australia.
Received my meter yesterday, assembled it this morning and have already
put it to use. It assembled in a little less than one hour. Great board
layout, instructions and photos. Everything was incredibly clear.
I don't how I managed to get along without one of these for so many
years. I'm having a ball with it!!
Thanks,
Roger
Just a quick note to let you know that I've once again recommended
your lc meter. I've had mine for over a year and couldn't be happier
with it. I'm not the sharpest electronics guy so the auto ranging
feature is great for me. Fantastic unit.
The inductance side of it is so bloody sensitive and accurate. I use
it all the time when winding coils for my super, long range, picks up
stuff that your CC radio won't, DX Crystal Radios. The slightest
difference in spacing or turns is noticeable with your meter. I
couldn't get by without it.
Thanks again, Kirk
I have had your L/C meter (assembled) for over a year. It is the end result
of buying several pieces of eqpt. that did not meet my needs. I am so
pleased with it's performance that when a fellow ham inquired about a
Boonton L/C meter I had for sale that I steered him to "Almost All
Electronics" and he says he has one of your meters on order. I have sold all
of the items I bought (none satisfactory) at a loss and I have two heathkits
(copy of GR LCR bridge) and the Boonton left--I may have to eat these.
Thanks for building stuff that works-
. Ralph.
Tell you what Neil, I like this 10 MHz TXCO our daughter gave me for Christmas. I let
it run for 5 days, then tweaked it with a GPS-disciplined counter and ever since then it's
been stable at no more than 0.5 Hz either side of 10.000000 MHz. Pretty durn good for a
$40.00 standard if I do say so!
I've also been very pleased with with my LC IIB. Thanks for these unique, high quality
products and good deals.
In this version, power is obtained from a jack on the rear panel.
Bill
Neil, This note is from Tim.
Neil I received my L/C Meter this week and I want to thank you Sir For the Great Product.
I have checked it out and I am 110% pleased with it. I already gave the China Junk a shove
to the bottom of the junk drawer(except the leads and Battery). Thanks again for the
product and Fast Shipping,and I will be looking at your site at other things I can
Use...Tim....
That's 10 days to Italy, just a benchmark for those who may wonder how long it typically takes to ship there.
I finished up my LC meter kit this afternoon. Took about 2 hours total time to put
together. It worked great first time. Instructions were good and if I had any problems on
parts placement, I just reviewed the pictures from future steps. A fine product and I'm
sure I will get a lot of use out of it.
Thanks Dick
Hi Neil
Just mailing to let you know the meter arrived about an hour ago and was well worth the
wait I am very very impressed with the sensitivity and accuracy of this instrument
especially on the nH range where my Wayne Kerr 4225 is just guessing ! and love the set
zero function .
Best Regards
Ron
Hi Neil,
Absolutely marvelous! (L/C Meter IIB) Beats our expensive
Wayne Kerr hands down for accuracy and drift.
Good luck with it.
Best regards
Martin
Design Engineer
U.K.
Hi Neil!
Just wanted to mention that my C-520 frequency display - two line, blue - arrived July 27/06. I hooked it up, but only the blue display light came on. I opened it up - and in shipping one of the boards that plugs into the other board had become detached. I plugged it back in and it worked. I wanted to mention this for your future reference in case others have a similar problem - it is a very easy fix.
(I usually put a rubber band to hold the boards togather but must have forgotten)
Initially there was a problem with the digits bouncing around - but this was resolved simply by grounding my TS-520SE as it should be. Now the display is very stable. Again, if others were to have a similar problem, this would be a good starting place for them to check - make sure your transceiver is grounded as it should be.
I found using a small alligator clip with a rubber boot worked great for tapping off the power for the C-520 from the TS-520SE power socket.
I am very impressed by the C-520 display - very nicely constructed inside and out and works very, very well.
Many thanks for an excellent product!
Phil
Hello Mr. Neil! Thanks for another super Digital Display Kit, the DFD3. I just finished
building the kit for my Kenwood TS 520, works like a champ.
Many thanks also to Bernie, . I used his recommended connection to the TS 520.
Thanks again. Bucky
Neil,
Finally found time to construct your lovely DFD3 display kit. Well
done! Here is a pic of the result attached...
Seems to work well as I learn the Ins and Outs of programming it. I
could not set the offset to 50 MHz as you pointed out in one of your
emails. As soon as I set it to 50, it reverted to something around 33
MHz. So I set it to 10 MHz as the least significant digits.
Only one question regards the 100 ohm resistor in the kit. It was not
mentioned in the assembly instructions but I did have to find a 10k
resistor per the instructions. I wonder if the 100 replaced a 10k as
the constrast pot had to be set near an exteme to get the display to
light up. Works well no matter what.
Btw, I found that a 470 ohm, 5 watt resistor works wells for the
backlight while using 13.8 VDC for the supply.
Anyway, thought you might want to see what I built and hear that I am
quite pleased with your product. I DO enjoy building a kit now and
then...
73,
Paul
Hey Neil
Your Digital Display unit in a HQ-145...
Anthony
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Neil,
Hope you are doing fine. Just wanted to update you about my DFD3 I purchased
2005.
It is still working fine and a much value addition to my HW-101. I enjoy the
biggy display I purchased with the DFD3 kit. The DFD3 really is nice when
calibrating my HW-101 band frequencies. I have enclosed pictures I previously
sent you.
I am currently have my HW-101 with the DFD3 on 20 meters using PAR Electronics
ENDFEDZ EF-20H 20m end fed dipole antenna.
Cal
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Dear Neil
I send you 3 photos with your DFD-2 (101) working in my FT-101.
TNX for all.
EA4KB
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Neil;
Just got your LC meter in the mail today and took about an hour and a half to build it. An unqualified success, as expected. Good instructions, easy assembly, and it operates perfectly.
Thanks a million,
73,
Ken
Neil,
I mounted the TCXO board into a 4 x 6 enclosure along with a small toggle switch and power
LED, and spent a good portion of the weekend getting all of my frequency based instruments
to at least be in agreement with your reference.
I would like to thank you for making this board available at such a reasonable price. Each
time I looked into building such a device the cost of the parts alone in small/single
quantities would have been more than you price for the assembled and calibrated board--the
four AMP BNC connectors alone would raise heck with a $20 bill...
You are providing a great service to the HAM and hobbyist community, I will do my part to
make those I know aware of same.
-cliff-
I received my kit (L/C Meter IIB) a few hours ago.
I had it assembled and working in about 1½ hours, very nice kit and easy to assemble. I
was surprised to find that some of the inductors I have are off by quite a bit, but the
one I wound myself was nearly dead on.
I would like to give some credit to Ian C. Purdie for helping me decide to purchase the
kit from you. I was thinking that I need to get a meter for measuring inductors. I did a
search on Yahoo and came across Ian’s page at http://my.integritynet.com.au/purdic/lc-meter-project.htm.
After reading his review I decided to purchase the kit from you.
Thanks,
Richard
Dear Neil,
The IIB meter is, simply, outstanding. It is neat, compact, intuitively easy
to use and above all its accurate. Very accurate!
Audiocom in the UK bought this meter for me last week as a made up unit.
Though I subcontract design for them, this piece of gear is (a) staying here in my
lab and (b) staying here!!
IIB is an outstanding piece of engineering Neil, and at the price
NO engineer should be without one. I'd recommend the IIB without
any reservation.
Sincerely Donald
Hi Neil
Just finished up the DFD3 frequency display for my Yaesu FT-101 and it works great. It was
a charm to set up using WWV and CHU for my calibration frequency.
It was a charm to build with very clear instructions and information. You attended to my
problem with a corrupted chip promptly and professionaly which was very much appreciated.
The DFD3 is rock solid and it appears as if the VFO of the 101 is rock solid as well as
the frequency varies only a few HZ over a period of several hours. I can tune the radio to
a specific frequency now and feel very confident that I am on that frequency precicely.
Thanks for producing this very worthwile unit - it gives a radio with an analogue dial a
new lease on life.
LOVE IT ! ! !
Harold
Received it, built it, tried it, like it!
You've got a really elegant little device here. Clean internal design,
very nicely kitted up for assembly, easy to use, highly functional,
very affordable. Thanks for making it available!
Dave
Neil,
I ordered the L/C Meter IIB last weekend and it arrived very quickly.
I read the reviews, including the ones on eham that grumbled about the instructions.
Actually, I thought they were pretty good, but I waited until today (Saturday) when I
could block out enough time to not be rushed. After a leisurely 3 and a half hours it
was all done, and working great.
I measured a 0.1 uF, a 0.01uF, then what I thought was 22 pF, but the meter said it was
220 pf. Then I found a 47 pF and the meter read 46.5 pF. Great stuff !!! I have an
air variable cap and some compression trimmers that I can't wait to identify.
I decided to buy a meter because I am going to wind some inductors, and I want to know
what I'm getting for inductance. I first learned of AADE from the ARRL book
"Experimental Methods in RF Design" by Haward, Campbell, and Larkin.
Thanks for making the design available. If it doesn't make you rich, you can at least
take pride in having produced a well designed, affordable product that many folks
admire and appreciate.
Best wishes for success in 2006,
Roy
Hello Neil,
I ordered a LC meter last weekend, it arrived late this week. I am
very (!) very pleased with it --- it helped me turn a large number (
several thousand) components that I had largely grouped and attempted
to label with values into a very useful parts set for my workbench,
in about 2 hours time. In particular, I was able to correct mis-
labeling I had caused when I was trying to measure inductance with an
Autek RF-1 (which does a passable job with capacitors, but is
completely useless with inductors as far as I can tell.)
Anyway, congrats on a *very* fine design and product...
Dave
Hi Neil!
I have just built (About 1.5 Hours) the kit which arrived this morning. The only
difficulty I experienced was being able to read the "681" on the 680 pF cap. (I
guess that comes from having fairly old eyes!) As this was the only one left I assumed it
must be the one, and it proved to be a good decision. I played with the unit and my junk
box for a while, and can only think to congratulate you on a truly impressive product. I'm
thrilled, and particularly impressed by the inclusion of the fixture which eliminates
flying leads for low value components. A must for the VHF/UHF practitioner.
I cannot imagine a more useful tool to help in particular with design of the inductive
elements of L/C filters.
Again, congratulations on a fine product. Please feel free to quote any of this as
testimonial in your publicity; the L/C Meter IIB does everything you claim, and represents
amazing value for money when compared with other devices of similar capability.
With kindest regards,
Nick
Hampshire, England.
Hi Neil,
I have received the LC Meter II last Friday (June 24th), have put it together all the way
in half an hour, following the instructions attached, and got it to work right away. SUPER
!
I have to thank you for this excellent piece of equipment, for it's essential yet perfect
engineering and, last but not least, for the logistics of the delivery.
Great job Neil !
Alberto.
Italy
Received the meter, Assembled in 3.5 hrs. Seems to work fine. Since
I purchased your DFD-2 as well. That's 2 for 2. Good work.
Bob
Hello Neil,
Just a short note to let you know this morning I have received the L/C Meter. This
afternoon I have
started to assembly the kit, and it has taken me just under two hours to have it working
and closed on
its case.
I have been testing it with a few caps and coils, and it is simply great!.
Thanks a lot.
Rodolfo
(Tenerife -Canary Islands)
Yesterday I ran across a filter design software that I have to say is a good
one for a change. It also prints the schematic and parts list for the filter. Now it is a
Windows only app as it's coded in Visual Basic. The name of the app is "AADE Filter
Design" amd is now freeware. You will get a nag screen the first 10 times you use it
which is an ad for the authors other stuff. I tested that and after 10 restarts of the app
it was gone. I designed a Chebyshev Low-Pass filter with a cutoff freq. of 35 MHz as quick
as you could say scat, well almost. You can also test the design in which it displays a
graph that it calculates shown the db attenuation. Anyhow, if you want a good free app for
any type of filter network, the link is below.
AADE Filter Design;
http://www.aade.com/filter32/download.htm
Best,
Will
It is very nice software and now that it is free it is really a great deal. The pop-up
ad you have to sit through is for the L/C Meter IIB. I have both this one and the
original one and they are absolutely great little devices. Pricing of MFJ equipment
with quality and accuracy that MFJ only dreams of.
You can check out error analysis here: http://www.aade.com/lcm2binst/HP.html
Specifications are here: http://www.aade.com/lcmeter.htm#specs
And you can even download the instruction manual to check it out in more detail.
This explains why the program is free:
The program has been a hobby of mine for over 25 years.
For the last 7 years I sold it as shareware but total sales for those 7 years was less
than one months sales of my hardware so I decided to give it away to attract visitors to
my web site and call attention to my hardware products.
I don't know this guy, I've just been a VERY satisfied customer for MANY years.
--John
And of course, you can't please everybody.
Hi Neil,
I downloaded the Free Filter Program that was on your web site and all I
can say is that it was a big waste of my time.
Why did you or the person who wrote the program keep having a pop up
window advertising to buy your LC meter or whatever it is???
I thought that some good person was going to offer this free program to
help others but instead was designed to make someone money.
Very disappointed, Frank
Hello Neal:
A number of years ago I built your LC meter, when it was featured in Electronics magazine.
While I do not do as much electronics today as I did then, I want to say thank you for a
wonderful project and very nice piece of test gear. Keep up the good work. I would
recommend this meter to anyone who needs to measure capacitance or inductance.
Tom
My name is Edgardo ( - Italy)
I got your kit. Everything is ok, the L/C meter is working well. I'm very happy. It is
very good.
I have only a question regarding components I received from you and that I didn't used.
In a little plastic envelope there are a little pc board (about 1x2 inches with holes at
same spacing of the vertical spacers), a 8 pin female connector, two threaded bananas and
two nuts.
It seems to me there is nothing on your instructions about this.
Please Neil, may I know something?
Thanks, Ed
This is surface mount adapter works similar to the unit on pictured
on my web site at
http://www.aade.com/lcmeter.htm save it for when you start to
use surface mount parts.
Hi Neil
I received the L/C Meter IIB around noon today and promptly put it
together. Sort of reminded me of all the Heathkits I have assembled.
Anyway, I powered it up and it works perfect. I just wanted to compliment
you on a fine product. Thanks for the prompt shipment.
I am not that easy to impress being an electrical engineer for 35 years
but I'm impressed.
> 73,
> Bob
Neil,
Just a quick thanks for your prompt shipment of my order for the IIB L/C meter
kit. I've recently gotten back into the SWL/BCB/UTE DX hobbies after a
long hiatus and I expect it (and your free filter design software) will be
quite helpful in some homebrew projects. It's up and running-checks against
several caps and coils of known values agree within expected tolerance. Great bang
for the bucks!
-Richard
Hello Neil,
Your L/C meter design works perfect.
I saw you can do magic things with the PIC processor, some
factories like HP need much more electronic parts.
I have a lot of SMD spare parts with no label, with your meter
design there are no secrets (hi!).
I'm for 10 years in the home brew but I have always problems
with the multiplier system on coils, and now I can make make
my own coils!
73's Cor
Hello Neil
I came up with a small issue for this meter. I have a 41 inch square loop,
wound with 24 turns of #14 insulated wire. The frame is 1 1/4 inch dia. pvc. Here is a
link to the one I modeled.
http://www.america.net/~boo/html/loop.html
I added three turns more to use up the total spool. The turns are tied with nylon ties
between each arm.
It measures 4.2 mh on the meter. When I peak the antenna for 25.2khz using polystyrene
capacitors, the calculated inductance is 2.1mh. I did this at two different frequencies
and came up with the same results using the
capacitance values from the meter. Any ideas about this? Other than that, the meter is an
excellent device.
Richard
I have had a report or two about measuring large loop antennas or
metal
locator (treasure finder) coils giving problems. Don't know why.
Hi Neil
received the L/C Meter IIB kit today [Monday 6/28/04].
Had it "up and running" in 2 1/2 hours......no problemo.....
nice kit.......good instructions........your shipping speed is
fantastic!.......thanks again.......
George
Dear Neil:
Excellent work on your LC meter. I purchased the kit form.
I received mine in the mail today and had the pcb populated and the case assembled in
under 1.5 hours.
The lc meter worked right away.
I tested it against another precision handheld C meter I had using various capacitors. I
also tested a 150nH and a 1mH inductor with it. The measurements matched expected results.
Keep up the good work.
Tim
Minneapolis, MN
Neil,
I just want to wish you a Happy New Year! I received my LC Meter the
other day and had it assembled in short order. It works GREAT! Thanks so much
for producing such a fine instrument.
A comment about your SMD test adapter provided with the kit: It is
great! Want to improve it just a little more? Include two female pins as
used in DB style computer connectors and show them soldered standing
vertical, side by side, on the board. These are perfect for inserting
leads of dipped silver mica and ceramic capacitors and toroids into for
measurement.
I'm please to say I've linked to your web page from mine with a
recommendation to purchase your LC Meter. It's a fine thing!
Happy New Year!
Tony
Neil,
I received the meter yesterday and am very impressed.
Very easy to use and a great addition to my lab. I picked
your design over getting an HP LCR meter on Ebay.
Great stuff!!
Bruce
I just built a L/C meter kit called the L/C Meter IIB from "Almost All Digital
Electronics", http://www.aade.com. The kit cost $99.00 (US) and had a few features
that would appeal to PI coil makers as well as matching critical capacitor values in the
Hammerhead circuit. The above web site has a detailed comparison to other well-known LC
meters. The assembley instructions are also located there.
The unit is self-calibrating and self-zeroing. When in the inductance mode it subtracts
the residual inductance of the shorted test leads and when in the capacitance mode it
subtracts the residual capacitance of the open test leads. This ensures that low value
measurements are accurate...and they are! It comes with a component test fixture that
allows surface mount and leaded L/C components to be easily tested.
The unit comes both assembled as well as in kit form. I chose the kit and it went together
in about 2 hours with no problems. One unique feature is that two capacitors come in a
separate envelope and they are selected to be a combined standard value when installed
together to form the basis of measurement accuracy.
Here are some uses of this LC meter for PI coil makers and Hammerhead builders.
Measure the capacitance of coax wire, shield to center conductor. This is important when
trying to make very fast coils with the lowest possible total capacitance. You may be
surprised to see how much capacitance is in you coil coax lead to the control box. A good
range will be between 16pf and 25 pf per foot.
Measure the capitance of the shield to the coil. Just clip one meter lead to one of the
coil wires and the other meter lead to the shield and see how many 100 pfs your shield
adds to the total capacitance as seen by the pulse circuit and is reflected in the value
of the damping resistor. Remember higher values of damping resistor means you have less
capacitance in the circuit and this means a potentially faster and more sensitive coil. So
if you want to reduce the coil to shield capacitance this LC meter is just the thing to
see effect of changing the spacing between the coil and shield, using different wire
sizes, using thicker or thinner insulating coil wire, or using different types of wire
insulation, kynar, teflon, vinal, etc. Remember, the fewer turns you have in the coil
(with the desired inductance) will result in a lower shield to coil capacitance as each
turn within the coil adds to the total measured capacitance. If you are planning to use a
series current limiting resistor in your TX coil circuit, you can always a thinner wire
and make a faster coil. 50 ft of Radio Shack Kynar wirewrap AWG 30, wound on a
10.375" diameter coil form with 18 turns will make a 380 uH coil as measured by this
LC meter.
Coil inductance measurements can be found by using the on-line calculators such as:
http://my.athenet.net/~multiplx/cgi-bin/airind.main.cgi
This calculator will get you in the ball park but are not very accurate when winding a
multi layer coil that you are going to tightly wrap with plastic spiralwrap to space the
shield. Thinner wire, spaced more closely together, gets you higher inductances. This
means that you get the desired inductance (say 300uH) with 17 turns of AWG 30 Kynar
wirewrap vs. 21 turns of AWG 22 stranded hook up wire. The coil to shield capacitance of
the AWG 22 stranded hook up wire will be higher than the thinner Kynar wire bundle. This
meter is just the thing to see the results. Some of the results are counter intuitive!
My old workhorse LC meter is a tube-based Tektronix 130 LC meter that has a maximum
inductance measurement of 300uH full scale. If I want to go higher I need to add a known
inductor value in parallel with the unknown inductor and use the parallel inductor formula
to calculate the value that is larger than 300 uH. This is not very convenient when
winding coils in the 300uH to 500 uH range.
When I finished with the L/C meter IIB kit, I measured and adjustable inductor set to 300
uH. Then I measured the same inductor on my Tektronix 130 and it was exactly 300 uH. You
can't beat that!!! Even though the web site and the meter specifications claim it is
accurate, I had to see for myself. I'm convinced!
In the Hammerhead circuit, Carl mentioned that C17 and C18 are candidates for being
matched to get the same response from both inputs of the integrator stage. This LC Meter
IIB has a matching mode that will very accurately help you find matched capacitor pairs.
Considering the percision of this meter, it's ease of consuction, relatively low cost and
value to PI experimentors, I wanted to share this with the Geotech Forum members.
bbsailor