Re: KitsAndParts uni-VFO kit
On Wed, Mar 26, 2025 at 01:21 AM, chuck adams wrote:
I'll do a video of the patented paste applicator.?
looks good.? looking forward to your video.? I play with hot air but have never tried a skillet.? I put a blob of paste on whatever scrap is at hand and apply with a toothpick.? on an indulgent whim I picked up some of these.
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--
¡ì97.313?? Transmitter power standards.
(a) An amateur station must use the minimum transmitter power necessary to carry out the desired communications.
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Re: KitsAndParts uni-VFO kit
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after ruining a handful SOIC parts trying to hand solder them, i spent fifty bucks and bought one of these hot plates: ?
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i then spent a quiet afternoon with a couple of thermocouples, figuring out how to mimic the heating profile for solder paste without a fancy PID controller (pro tip, trying to use the PID "controller" built into the hot plate will brick it).
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it turned out to be surprisingly easy. my lab notebook isn't handy so i am working from memory but it was something like: put the prepared board on the hot plate, turn it on, set the temp to 180C, when the temp gets to 180C, wait 30 seconds, set the temp to 230C, when the? temp gets to 230C, wait 15 seconds, turn off the the hot plate, wait 15 seconds, remove the board and let it finish cooling.
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and after a lot of poor solder joints from mis-applied solder using other DIY methods -- too much, too little, in the wrong place -- that created re-work (life is too short for re-work) i started kester solder in syringe tubes, which pretty much solved the problem.
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cheers bill k7wxw
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ps - how big should i cut my copper clad board for that circuit because i hate wasting my precious copper clad board?? i figure it out by laying out the circuit on graph paper before i glue a single pad down.??? and, yes, gel-style superglue is your friend.
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Re: KitsAndParts uni-VFO kit
Your job does look great Chuck!
I wonder if you could do this in the kitchen oven?
I've checked the temp before, it is right on.
73,
Gary
WB6OGD
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Re: Label Printing (was Jackson and Garner topic)
Thanks for the info on the labels Chuck.
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-Albert
KI4ORI
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Re: ADC 40 (and ADC 20) crystal filter info
Steve,
Yes, the output from the G3URR testor is related to the crystal's Q. In my G3URR/W7ZOI measurement setup, I use a diode doubler on the output (from a G3URR article in the ARCI QQ) to a pair of banana jacks to measure the Vp with a DMM. If a crystal shows a lower 2Vp than the others in the test batch, then it is a suspect for use in a filter. N6KR had suggested this measurement way back in the early '90s (measuring the crystal's output voltage) which is related to its "activity," a function of its Q. Those Vp measurements are relative, not absolute, and they help?in sorting them when one is doing the measurements. I recall Chris Trask designed a measurement setup where he could derive all the needed crystal parameters in one set of measurements per crystal. i've a copy of his article somewhere.
Regards, Walt K3ASW ??
On Mon, Mar 24, 2025 at 5:40?PM Steve Ratzlaff via <ratzlaffsteve= [email protected]> wrote:
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
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Re: KitsAndParts uni-VFO kit
Looks great, Chuck! Does it work??? 73 Mike M.? KU4QO
On Wed, Mar 26, 2025 at 2:21?AM chuck adams via <chuck.adams.phd= [email protected]> wrote: Here is my second pass at the skillet method.? I am a fast learner,
gotta give me
that.
I'll do a video of the patented paste applicator.? We don't need no
stinking syringe.
No solder bridges ever again.? EVER.
This thingy is the size of a postage stamp.
chuck, aa7fo
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Re: KitsAndParts uni-VFO kit
Looks good!? Better than hand soldering. Used to be able to do that ¡.. 73 de VK2HHS Henrik
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On 26 Mar 2025, at 18:30, Kirk Kleinschmidt, NT0Z via groups.io <sohosources@...> wrote:
? It's a certain kind of ridiculous how small those have become!
Considering my semi-senior eyesight, I have done well with hot air removal and replacement of tiny ICs, but I haven't yet tried the frying pan method...although I did buy a new electric pan -- and a used toaster oven -- some 11 years ago! The pan is still in the Black Friday box...while the toaster oven is staring at me now from the upper shelf...
Man, years now go by like weeks used to...
Thanks for your efforts. We appreciate them,
Kirk, NT0Z Rochester, MN
My book, "Stealth Amateur Radio," is now available from
www.stealthamateur.com and on the Amazon Kindle (soon)
On Wednesday, March 26, 2025 at 01:21:15 AM CDT, chuck adams via groups.io <chuck.adams.phd@...> wrote:
Here is my second pass at the skillet method.? I am a fast learner,
gotta give me
that.
I'll do a video of the patented paste applicator.? We don't need no
stinking syringe.
No solder bridges ever again.? EVER.
This thingy is the size of a postage stamp.
chuck, aa7fo
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Re: KitsAndParts uni-VFO kit
It's a certain kind of ridiculous how small those have become!
Considering my semi-senior eyesight, I have done well with hot air removal and replacement of tiny ICs, but I haven't yet tried the frying pan method...although I did buy a new electric pan -- and a used toaster oven -- some 11 years ago! The pan is still in the Black Friday box...while the toaster oven is staring at me now from the upper shelf...
Man, years now go by like weeks used to...
Thanks for your efforts. We appreciate them,
Kirk, NT0Z Rochester, MN
My book, "Stealth Amateur Radio," is now available from
www.stealthamateur.com and on the Amazon Kindle (soon)
On Wednesday, March 26, 2025 at 01:21:15 AM CDT, chuck adams via groups.io <chuck.adams.phd@...> wrote:
Here is my second pass at the skillet method.? I am a fast learner,
gotta give me
that.
I'll do a video of the patented paste applicator.? We don't need no
stinking syringe.
No solder bridges ever again.? EVER.
This thingy is the size of a postage stamp.
chuck, aa7fo
|
Here is my second pass at the skillet method.? I am a fast learner, gotta give me
that.
I'll do a video of the patented paste applicator.? We don't need no stinking syringe.
No solder bridges ever again.? EVER.
This thingy is the size of a postage stamp.
chuck, aa7fo
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Re: The qrptech Samuel L Jackson and Jennifer Garner Effect
Thanks Chuck, The Vevor is the one I looked at.? I can't imagine cutting .250 aluminum with it but should be OK for 1/16 or maybe even 1/8. I'll watch the video and I think there would be many ithers interested. Jim WB4ILP?
On Tue, Mar 25, 2025, 10:04 AM chuck adams via <chuck.adams.phd= [email protected]> wrote: 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?
On 3/25/25 05:01, Jim WB4ILP via 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
>
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Robin,
those are not crossed tweezers (as in self gripping).? That is
what I prefer to use.? I bought a pair from I think TEengineering
but the are similar to these Hakko tweezers:
The work but I prefer the crossed tweezers.
Thank you.
Jim Pruitt
On 3/25/2025 10:07 AM, Robin Midgett
via groups.io wrote:
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No magnetic issues with these:
On Mon, Mar 24, 2025, 2:09 AM
Jim Pruitt WA7DUY via <jpruitt67= [email protected]>
wrote:
I don't know if anyone else has
run into this.? I do quite a bit of smd soldering or try
to.? I have bought many many cross tweezers from several
sources that claim they are stainless steel.? The problem
is that they are either not stainless steel or are a very
low grade as they are magnetic.? Tonight I was trying to
set a couple 1206 rf chokes and my stainless steel magnets
kept grabbing the part and not wanting to let go!? How
does one know if the tweezers are actually non magnetic?
Thank you.
Jim Pruitt
WA7DUY
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I took the photo after the first solder bridge removal.? I reheated the board and the Microchip
slipped into perfect alignment.? I have to get some solder braid. Any particular brand and
mesh size?
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Re: The qrptech Samuel L Jackson and Jennifer Garner Effect
I have a band saw to cut boards, but it doesn't have the depth for large areas.
The hand held router allows me to cut boards to size and not take up a large
area in the garage for a table saw, and it's much cheaper.
The router came in real handy for the lip of the platform that butts up against
the left part of the shear mechanism.? The blade comes down against a steel
plate, the shiny thingy next to the right edge of the flat surface.
ASCII diagram:
-----------------------------
??????????????????????????? |
??????????????????? ---------
??????????????????? |
??????????????????? |
--------------------|
The missing section lower right is routed out.? If I remember
it required a dado blade for the table saw and I hated that
work.? Fingers are critical to moving and solder parts.
I'm not an expert at woodworking and at one time I had several large pieces
of equipment that were asking if I wanted to lose parts. Downsizing sucks,
but we can't take it with us.
I'll see if I can do a better set of photos.? Went to ACE hardware after
lunch today and got 3 1/2" nuts and bolts to bolt the shear down. That
will also further prevent any slight variation in board cutting.
cheers yourself,
chuck, aa7fo,? who also loves lower case from the unix days
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On 3/25/25 16:08, bill K7WXW via groups.io wrote: thanks for sharing the photo. i have been trying to figure out how to build a platform for shearing PCB, built two versions that didn't work as well as I would like. question: what did you use the router to do? i suspect something on the shear side of the platform but it is hard to see in the photo.
cheers, bill k7wxw
_._,_._,_
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ADC status, SMD learning curve and a thought
1.? The audio section is lacking in gain, for some reason, and it just may be the
reason why Doug Hendricks, KI6DS, and Steve Weber, KD1JV, switched to an LM386
in the kit version.? I'll ask Doug when I see him sometime later.
So the delay is going to be a sidebar where I build two audio amps on
<> designed by Diz, W8DIZ <sk>,
and the second one by Robert Cerreto, WA1FXT.? One of these may replace
the original design, so the workbench is covered with stuff.
2.? I have three VFO kits.? A uni-VFO from KitsAndParts, another from the
QRPGuys and the last from QRP-Labs.
SMD Learning curve.? So, I thought I'd take an hour and learn how to do
SMD.? Went to my favorite URL, YouTube, and looked at some videos.? Went
to several sites for solder paste and looked at the curves.? I had ordered
a 6" cast iron skillet yesterday off amazon and it got here at 6am.
I took a small hot plate in the garage and run two tests.? One with the
temp control at max and a second run at medium.? With the solder paste
manufacturers curve and my data, the graph is shown below.? Having
learned that the manufacturers curve is really determined by the
thermal properties of the FR-4 material in the PCB and not so much
the solder paste.
Last year, we had work done on a fridge.? O*(*&P(*)( things are the worst
appliance in the house, but the most important.? The kid left behind a
Milwaukee 10:1 IR temperature gun.? Valued at $90 from HomeDepot. If
the kid every calls he can have it back and I'll buy my own.
The skillet curve means the job will take about twice and long, but
should be well within the parameters of the FR-4 board material and
the 450 deg F limit recommended by the paste guys.
I fired up the setup from a cold start with the control set at medium.
I used the gun to let the system get to 365 deg F, shut off the power,
waited 30 seconds or so and removed the skillet from the plate and
removed the board to a pyrex glass plate.? Second photo is the results.
Had two solder bridges on the big chip.
Didn't have copper braid, so heated the first bridge and dropped the
board (on purpose) on the desk and the solder exited the board. For
the second bridge I wasn't as lucky and the solder stuck between
the two resistors R1 and R3 and cap C3 in the bottom center.? So
fixed that we are good to go.
Note, the Si5351A 10-MSOP package came out perfect.? I just have to
perfect the syringe application to keep from getting too much in places
so that bridges don't occur.? You experts can see that this work is
way below par, but shown here for getting ideas on where I went wrong.
I'm no longer scared to tackle a SMD kit, but then fools rush in.
3.? Going back to the Manhattan project.? I was talked out of doing a
DC receiver.? The thought being that the project would be too simple
and too boring and just a toy.
I watched the latest version of SolderSmoke and the status of the
DC receiver challenge.? I'm thinking that 50 built is way too low.
Can I possibly interest a group of you to take on the challenge
and show that qrptech has the best group of builders on the planet?
I really looks like a fun project and not too serious and not too
complex.? Let the world know you exist.? What?? 4-6 hours max?
You have the parts.
chuck, aa7fo
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Re: The qrptech Samuel L Jackson and Jennifer Garner Effect
btw, if you really like to live dangerously, you can cut PCB with a micro table saw like this proxxon i bought for other projects: ?
?
easier to make square corners. also easier to lose a finger. proceed with caution.
?
cheers bill k7wxw
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Re: The qrptech Samuel L Jackson and Jennifer Garner Effect
thanks for sharing the photo. i have been trying to figure out how to build a platform for shearing PCB, built two versions that didn't work as well as I would like. question: what did you use the router to do? i suspect something on the shear side of the platform but it is hard to see in the photo.
?
cheers, bill k7wxw
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No magnetic issues with these:
On Mon, Mar 24, 2025, 2:09 AM Jim Pruitt WA7DUY via <jpruitt67= [email protected]> wrote:
I don't know if anyone else has run into
this.? I do quite a bit of smd soldering or try to.? I have bought
many many cross tweezers from several sources that claim they are
stainless steel.? The problem is that they are either not
stainless steel or are a very low grade as they are magnetic.?
Tonight I was trying to set a couple 1206 rf chokes and my
stainless steel magnets kept grabbing the part and not wanting to
let go!? How does one know if the tweezers are actually non
magnetic?
Thank you.
Jim Pruitt
WA7DUY
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Label Printing (was Jackson and Garner topic)
Go to officemax or staples and look at the avery stuff.
They make a letter sheet size page for laser printers.
It is clear and the one I use has matte finish and not
the shiny stuff.? Make a front page layout and print
on plane paper first to cut and fit to make sure
everything is in place.? No use wasting a valuable
sheet of label material.
Went to my old friend DeepSeek and asked and got the
Avery #4397 number.? One peek at Amazon.com and below
is the result.? You can see why I recommend you play
with paper first before committing to the final print.
IMHO.? Note that DeepSeek lied again and gave the old
number and not the current one.
If you use only 1/2 or less, you can refeed the remainder
for another project later.
Take your credit card with you.
chuck, aa7fo
BTW.? I'm going for just the 18" brake.? I have no use
for the other functions.? Just for a note.
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On 3/25/25 08:06, Albert Marsh via groups.io wrote: I have also considered buying a combination slip/roll/break/shear for many projects.
Hey Chuck, I am also curious about that front panel. Very nice lettering and layout. Please tell us your secrets.
-Albert
KI4ORI
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Re: Group Introduction: If you're going to post on the group, reply here!
Welcome to the group, Allison. We're glad to have you :)?
On Tue, Mar 25, 2025 at 8:28?AM ajparent1/kb1gmx via <kb1gmx= [email protected]> wrote: Allison/KB1GMX
?
Been around the QRP world for 25+ years.? Built a lot of gear?
about have are VHF and up alll QRP.? IF I need QRO its just
another box.
?
?
?
Allison
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bill K7WXW
Henrik Stenstrom
Kirk Kleinschmidt, NT0Z
Robin Midgett
