Miniature SMD inductors are often strongly magnetized themselves! They're the worst for this problem - they seem sometimes strong enough to magnetize tweezers!
?
I finally stopped worrying about the tool materials so much and bought a cheap watch demagnetizer. It's hardly ever needed, but it's right there on the workbench ready to deal with any small tools that have a problem...
?
--
Mario Vano
AE0GL
|
Re: The qrptech Samuel L Jackson and Jennifer Garner Effect
I use the PCB on all my PCB work.? It'll handle anything that I have from abcfab and
that is about everything he sells.? :-)
I have used it on 0.030 Al and it is rated for 1/4" max, but there is no way I am ever
going to need that.? I will buy an 18" brake in a month or two to go back to making
enclosures again.
You see the platform I made to be able to cut at 90.00000 degrees? OK, close.
There is a AA7FO secret.? Get some C clamps and use some boards to clamp
in place to hold the right edge and the opposite edge from the blade.
The torque generated is impossible to oppose by hand and the board will
rotate by a degree or two when the edge gets to the last part of the cut.
Been there.? Done that.
Here is the check, and I wrote this up decades ago.? Take a scrap piece of
PCB.? Cut all four edges in order or rotation, either CW or CCW. Then
measure the corners to see if they are indeed 90.0 degrees.? You've
got the technique down pat if you get close enough.? I know, it's an
OCD thing.? I attribute to two years in kindergarten and knowing
how to stay in the lines.? :-)
FYI
chuck,? aa7fo,? local sales rep for everything you need
The shear is a Vevor at $133.99 on Amazon, but they probably
all come from the same sweatshop.
If I make a video for youtube, will more than 6 of you watch it?
toggle quoted message
Show quoted text
On 3/25/25 05:01, Jim WB4ILP via groups.io wrote: I have the brake and considered buying the shear. How well does the shear work?? What thickness aluminum can it handle?? Is it good for PCB material?
Thanks !
Jim WB4ILP
|
Re: The qrptech Samuel L Jackson and Jennifer Garner Effect
I have the brake and considered buying the shear.? How well does the shear work?? What thickness aluminum can it handle?? Is it good for PCB material? Thanks ! Jim WB4ILP?
On Mon, Mar 24, 2025, 6:04 PM chuck adams via <chuck.adams.phd= [email protected]> wrote: Q:? What's in your wallet?
A:? Nothing.? I spent it all on lab equipment and parts.
Last year I purchased, from Amazon, a 12" shear.? Warning.? This puppy is
heavy and not for those with knee and hip problems.? Get a couple of HS
football players to come over for milk and pie to help you out. Free
shipping.? Priced about $125 USD.? Brand is covered up by fixture.
A few days ago I took a hand held router and made a platform to securely
hold the PCB material for cutting.? No plans available.? One of a kind.
I have 20kg of PCB material gathered over 30 years from abcfab on ebay.
He used to be in NE, but may have now relocated to FL.
My plan to use as much as possible by the end of Sept.
People may be thinking, how does the village idiot know how large to
make a board for a project.? Well, he doesn't.? Just make sure it's
large enough.? Shear away the unused portion when done.? Some of the
left overs can be used for little critters.
Thanks to all of you for sharing what you use.? It helps the rest of
us save some time and money.? Time being the most important commodity.
Enjoy,
chuck, aa7fo
|
Re: The qrptech Samuel L Jackson and Jennifer Garner Effect
That's a nice-looking little rig Chuck, and a good-looking front panel too!
?
Dave
AA7EE
|
Re: DE-5000 English manual
Thank You Steve ! Jim WB4ILP?
On Mon, Mar 24, 2025, 11:26 AM Steve Ratzlaff via <ratzlaffsteve= [email protected]> wrote: Here's one link to the DE-5000 manual in English. Note you must do the
initial calibration using the test leads you plan to use. You only do
that once, then you're good to go from then on as long as you don't
change the test leads.
Steve AA7U
|
Re: The qrptech Samuel L Jackson and Jennifer Garner Effect
I have a? way using the shear and a Harbor Freight brake that you might see in
some of the old projects.? Attached is the lower section of one in use.
thanks,
chuck
toggle quoted message
Show quoted text
On 3/24/25 16:03, Pete WB9FLW via groups.io wrote: Cuck, et al
Some may find this YouTube Video useful
"How To Make A Metal Project Enclosure"
|
Re: The qrptech Samuel L Jackson and Jennifer Garner Effect
Cuck, et al
?
Some may find this YouTube Video useful
?
"How To Make A Metal Project Enclosure"
?
?
?
?
|
The qrptech Samuel L Jackson and Jennifer Garner Effect
Q:? What's in your wallet?
A:? Nothing.? I spent it all on lab equipment and parts.
Last year I purchased, from Amazon, a 12" shear.? Warning.? This puppy is
heavy and not for those with knee and hip problems.? Get a couple of HS
football players to come over for milk and pie to help you out. Free
shipping.? Priced about $125 USD.? Brand is covered up by fixture.
A few days ago I took a hand held router and made a platform to securely
hold the PCB material for cutting.? No plans available.? One of a kind.
I have 20kg of PCB material gathered over 30 years from abcfab on ebay.
He used to be in NE, but may have now relocated to FL.
My plan to use as much as possible by the end of Sept.
People may be thinking, how does the village idiot know how large to
make a board for a project.? Well, he doesn't.? Just make sure it's
large enough.? Shear away the unused portion when done.? Some of the
left overs can be used for little critters.
Thanks to all of you for sharing what you use.? It helps the rest of
us save some time and money.? Time being the most important commodity.
Enjoy,
chuck, aa7fo
|
ADC 40 (and ADC 20) crystal filter info
The ADC 40 IF crystal filter uses three crystals with 150 pF caps
on the ends and in the middle. EMRFD? 3.21 mentions this type of
filter, known as Min-Loss and a derivative of Cohn's extensive
filter data. And 3.23, middle column near the top mentions the
exact filter the ADC 40 is using, and says the N=3 filter uses 146
pF capacitors and 181 ohm terminations. This fills in my missing
info on trying to make the ADC 20? 9 MHz filter--the filter uses
the same 150 pF capacitors, just the crystal frequency is
different.
I made a simple test fixture with 3 sockets to test the 9 MHz
filters. Transformers on input and output, 50:180 ohms, I'm using
FT37-43 with 10:19 turns, and the SA and tracking generator to
sweep the filter and find insertion loss and 3 dB bandwidth. I
bought a bunch of 9 MHz crystals and sorted them for frequency
with the G3UUR test oscillator, then matched them into sets, using
20 Hz max separation of crystals. All these crystals are the HC49S
(low profile) version--the normal HC49 tall version seems to be
"unavailable", though Mouser still lists the 9 MHz version, but
they have zero in stock, and "April 22 expected delivery" (those
are the crystal W7ZOI used for his 2020 paper about 9 MHz crystal
filters, available on his web page). All the crystals I got are
fairly low Q--40,000-70,000, with most in the 50k-60k range--so
nothing like the crystals W7ZOI used with much higher Q. And with
all my testing it turns out one can use the G3UUR test oscillator
to gauge how good a crystal is just by its output. I run the
output to the DSO, with the 10X probe. The DSO has the handy
on-screen display of Vp/p that one can enable. Perhaps due to the
change of the emitter resistor to 3.3k ohms, all these crystals
are completely stable in frequency and amplitude as soon as you
plug them into the test oscillator. My DSO gives the frequency
down to the Hz, which is what's needed to accurately match
crystals. Of course I don't touch the crystals but use tweezers to
handle them, so I don't add any heat to them. I happen to have a
few of the tall HC49 9 MHz crystals on hand, and they give
amplitudes in the 0.7-1.1 Vpp range. But the short HC49S crystals
all are in the 0.3--0.5 Vpp range--much lower.
73,
Steve AA7U
|
Measuring Crystals with NanoVNA and other tools
Found this good?w2aew video?
Measuring Crystals with NanoVNA and other tools
?
Actually learn what Crystal holder C0 means when crystals were actually stored in crystal holders.
?
I like how he actually shows the math.?
Uses his NanoVNA, DER EE DE-5000 LCR Meter, and other tools.
?
Talks about G3UUR crystal tester and the parameters you can determine from its results.
?
And the description of the video links to papers and notes.
?
73 Daniel KK4MRN
|
I was pretty excited about crystal measurements and crystal filter construction a few (many?) years ago. I homebrewed Jim Kortge's?PVXO and initially used a diode detector with good results. Later I built W1FB's integration of several W7ZOI circuits into one crystal measurement instrument that had appeared in QST.
Over time, I started using an?AD8307 type detector for the measurements. I'd built another W7ZOI circuit for this.
While writing the C# software for the PHSNA system originated by W5JH and N5IB, I decided to attempt to automate crystal measurements. I wasn't at all sure it would work, but in fact it worked very well and I was pretty proud of it. I could characterize a crystal and report Cm, Lm and Rs in about ten seconds. The starting point was to provide the approximate resonant frequency and the attenuation of the fixture with a short in place of the crystal. The program would?start a few hundred Hz below the resonant frequency?and move upward until the exact resonant frequency was found, recording the frequency and attenuation found, then scan down for the -3 dB point and then up from resonance to get the other -3 dB point. This was enough information to allow calculation of the parameters.
I've done crystal measurements with the nanoVNA. It's a wonderful gizmo, but the tiny size and those SMA connectors put me off a little. Yes, I use nanoVNA-Saver.
73
Nick, WA5BDU
On Sun, Mar 23, 2025 at 9:21?AM Tim Tyler II via <timtylerii= [email protected]> wrote: No problem, Michael,
Be sure to read K6WHP reply about two posts back in this thread; it is very comprehensive and will lead you to info that will help you decide which/where to buy yours. The nanovnausers IO group is indispensable.
I personally have a Nanovna-H4 and love it. Dislord firmware.
¡ªTim NC0Q
|
Re: S9 Generator Project? (capacitors for RF)
Jim -?
?
A member of the EEVblog forums did a teardown of the DE-5000, and it comes out looking pretty dang good for the price -?
?
?
It's already in my Amazon cart, along with a new Hantek 'scope. I'm just waiting for enough time to elapse since my recent flurry of Mouser orders, such that I feel able to spend a little fun money again!
?
Thanks once again Steve.
?
Dave
AA7EE
|
Here's one link to the DE-5000 manual in English. Note you must do the initial calibration using the test leads you plan to use. You only do that once, then you're good to go from then on as long as you don't change the test leads.
Steve AA7U
|
Re: S9 Generator Project? (capacitors for RF)
Here are pictures of the DE-5000 showing the dissipation factor of a Tayda 150 pF cap? with 0.005 vs. a high quality 150 pF cap. with 0.000.
Steve AA7U
toggle quoted message
Show quoted text
On 3/23/2025 7:11 PM, Steve Ratzlaff wrote:
Tayda Electronics also carries capacitors in that yellow blob shape; I've bought a bunch of them off and on. My DE-5000 LCR meter has a Dissipation Factor function that works in capacitance mode that I've found to be useful for judging these small values of caps used in RF circuits (and displays along with the capacitance value--you don't need to do anything to get the Dissipation readout). High quality good caps with very low dissipation will have a D of 0.000 even at the default 1 kHz test frequency (where I normally test caps but use 100 kHz for all RF inductors). Most of these Chinese caps will show a higher dissipation, sometimes up to 0.006 I've seen, with many in the .002--.003 range. If you need to use a good cap such as in a frequency sensitive circuit, I'd stay away from the caps that don't read 0.000 Dissipation factor.
73,
Steve AA7U
|
Re: S9 Generator Project? (capacitors for RF)
Thank You Steve for the tips ! I'll put that on my wish list. Looks like a great addition to the bench. Good DX ! Jim WB4ILP?
On Mon, Mar 24, 2025, 10:43 AM Steve Ratzlaff via <ratzlaffsteve= [email protected]> wrote:
Hi Jim,
Yes, that's the one but note that item comes with a bunch of
optional accessories. I buy the "main unit" by itself with no
accessories and put my own test clips on,? calibrate using those,
then don't need to do anything else. The unit comes from Japan,?
quickly.? Here's one with no accessories for the lowest
price--from eBay.?? ?? (You
need to download the free English manual separately.)
73,
Steve AA7U
On 3/24/2025 6:47 AM, Jim WB4ILP via
wrote:
Hey Steve,
Is your DE-5000 the one on Amazon for $138.00??
I'm not sure I'm ready to invest that much but do you
recommend it?
Thanks !
Jim WB4ILP?
On Sun, Mar 23, 2025, 10:11 PM Steve Ratzlaff via
<ratzlaffsteve= [email protected]>
wrote:
Tayda Electronics also carries capacitors in that yellow
blob shape; I've bought a bunch of them off and on. My
DE-5000 LCR meter has a Dissipation Factor function that
works in capacitance mode that I've found to be useful for
judging these small values of caps used in RF circuits
(and displays along with the capacitance value--you don't
need to do anything to get the Dissipation readout). High
quality good caps with very low dissipation will have a D
of 0.000 even at the default 1 kHz test frequency (where I
normally test caps but use 100 kHz for all RF inductors).
Most of these Chinese caps will show a higher dissipation,
sometimes up to 0.006 I've seen, with many in the
.002--.003 range. If you need to use a good cap such as in
a frequency sensitive circuit, I'd stay away from the caps
that don't read 0.000 Dissipation factor.
73,
Steve AA7U
|
Re: S9 Generator Project? (capacitors for RF)
Hi Jim,
Yes, that's the one but note that item comes with a bunch of
optional accessories. I buy the "main unit" by itself with no
accessories and put my own test clips on,? calibrate using those,
then don't need to do anything else. The unit comes from Japan,?
quickly.? Here's one with no accessories for the lowest
price--from eBay.?? ?? (You
need to download the free English manual separately.)
73,
Steve AA7U
On 3/24/2025 6:47 AM, Jim WB4ILP via
groups.io wrote:
toggle quoted message
Show quoted text
Hey Steve,
Is your DE-5000 the one on Amazon for $138.00??
I'm not sure I'm ready to invest that much but do you
recommend it?
Thanks !
Jim WB4ILP?
On Sun, Mar 23, 2025, 10:11 PM Steve Ratzlaff via
<ratzlaffsteve= [email protected]>
wrote:
Tayda Electronics also carries capacitors in that yellow
blob shape; I've bought a bunch of them off and on. My
DE-5000 LCR meter has a Dissipation Factor function that
works in capacitance mode that I've found to be useful for
judging these small values of caps used in RF circuits
(and displays along with the capacitance value--you don't
need to do anything to get the Dissipation readout). High
quality good caps with very low dissipation will have a D
of 0.000 even at the default 1 kHz test frequency (where I
normally test caps but use 100 kHz for all RF inductors).
Most of these Chinese caps will show a higher dissipation,
sometimes up to 0.006 I've seen, with many in the
.002--.003 range. If you need to use a good cap such as in
a frequency sensitive circuit, I'd stay away from the caps
that don't read 0.000 Dissipation factor.
73,
Steve AA7U
|
Re: S9 Generator Project? (capacitors for RF)
Hi Dave,
I highly recommend the DER DE-5000 LCR meter. It's the least
expensive meter that has 100 kHz selectable test frequency, plus
has near lab-grade accuracy. I don't buy any optional accessories
but use simple mini clips on short 2-3 inch pieces of buss wire
with banana plugs for the connections. There's an English manual
one can download free. Once you do the initial calibration you're
good to go. I find the default 1 kHz test frequency is good enough
for measuring small capacitors, but I always use the 100 kHz test
frequency to measure all RF inductors.
73,
Steve AA7U
On 3/24/2025 6:37 AM,
davidgeorgerichards via groups.io wrote:
toggle quoted message
Show quoted text
Thanks for mentioning your LCR meter Steve. Seems like a
worthwhile addition to the workbench. Having purchased cheap
capacitors in the past, I'm putting this on my list of wants.
Would you recommend it?
?
Dave
AA7EE
|
Re: S9 Generator Project? (capacitors for RF)
Hey Steve, Is your DE-5000 the one on Amazon for $138.00?? I'm not sure I'm ready to invest that much but do you recommend it? Thanks ! Jim WB4ILP?
On Sun, Mar 23, 2025, 10:11 PM Steve Ratzlaff via <ratzlaffsteve= [email protected]> wrote:
Tayda Electronics also carries capacitors in that yellow blob
shape; I've bought a bunch of them off and on. My DE-5000 LCR
meter has a Dissipation Factor function that works in capacitance
mode that I've found to be useful for judging these small values
of caps used in RF circuits (and displays along with the
capacitance value--you don't need to do anything to get the
Dissipation readout). High quality good caps with very low
dissipation will have a D of 0.000 even at the default 1 kHz test
frequency (where I normally test caps but use 100 kHz for all RF
inductors). Most of these Chinese caps will show a higher
dissipation, sometimes up to 0.006 I've seen, with many in the
.002--.003 range. If you need to use a good cap such as in a
frequency sensitive circuit, I'd stay away from the caps that
don't read 0.000 Dissipation factor.
73,
Steve AA7U
On 3/23/2025 6:36 PM, k6whp via
wrote:
Chuck,
?
As long as you're on about this, wonder if you (or others)
could keep your eyes peeled on Amazon or eBay for NP0 and or C0G
cap assortments to fill in the potholes in my collections.
?
NOT SMD but would love disk ceramic but willing to
compromise..
?
Also appreciate comments on something like this:
?
?
?
Thanks greatly!
--
William, k6whp
--------------------
"Cheer up, things could get worse. So I cheered up and things
got worse."
?
?
?
|
Re: S9 Generator Project? (capacitors for RF)
Thanks for mentioning your LCR meter Steve. Seems like a worthwhile addition to the workbench. Having purchased cheap capacitors in the past, I'm putting this on my list of wants. Would you recommend it?
?
Dave
AA7EE
|
OK Chuck,
?
A private message is winging it's way to you with the files attached.
?
Tom-N8TPN
|
Nick Kennedy
