Re: Help for an appliance operator
Vince, Ashhar didn't say what VTVM stood for - it's Vacuum Tube Volt Meter, we now call them DVMs, for Digital Volt Meters.
Just wanted to explain where the VTVM label came from. Ken, N2VIP
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On Aug 16, 2021, at 18:24, vince adams <vince@...> wrote:
?
Picture, please? 73 KD7TWW
On 09/17/20 12:36 PM, James Carroll via
groups.io wrote:
Hello
I ordered an Antuino thinking I would have an SWR meter to
help tune a random wire antenna.?
Right now, I don't understand anything about the Antuino.??
The first thing?that puzzles me is an item on the fifth
line of the display that is labeled "VTVM" and a number with
several decimal places that changes so frequently that the LCD
shows a blur with an occasional recognizable digit.? Before I
pack it up and return it, I would like to figure out what is
going on.
Any ideas?? Is there a URL for an explanation of this?
THanks.
Jim K9JEC
--
73, de Vince KD7TWW
In what year did the FCC mandate the 1500 Watt PEP limit for amateur radio station
power output? - Motorola Corp was formally named
"Galvin Manufacturing Corporation" (1928¨C1947)
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Re: Help for an appliance operator
The vtvm was a feature that I threw in. On the field one often needs a voltage reading to check on the batteries or fix some loose wires. I had one line available on the Arduino and added this feature. If you don't want it, I can send a new update to turn it off.
On Tue, Aug 17, 2021, 4:54 AM vince adams < vince@...> wrote:
Picture, please? 73 KD7TWW
On 09/17/20 12:36 PM, James Carroll via
wrote:
Hello
I ordered an Antuino thinking I would have an SWR meter to
help tune a random wire antenna.?
Right now, I don't understand anything about the Antuino.??
The first thing?that puzzles me is an item on the fifth
line of the display that is labeled "VTVM" and a number with
several decimal places that changes so frequently that the LCD
shows a blur with an occasional recognizable digit.? Before I
pack it up and return it, I would like to figure out what is
going on.
Any ideas?? Is there a URL for an explanation of this?
THanks.
Jim K9JEC
--
73, de Vince KD7TWW
In what year did the FCC mandate the 1500 Watt PEP limit for amateur radio station
power output? - Motorola Corp was formally named
"Galvin Manufacturing Corporation" (1928¨C1947)
|
Re: Help for an appliance operator
Picture, please? 73 KD7TWW
On 09/17/20 12:36 PM, James Carroll via
groups.io wrote:
Hello
I ordered an Antuino thinking I would have an SWR meter to
help tune a random wire antenna.?
Right now, I don't understand anything about the Antuino.??
The first thing?that puzzles me is an item on the fifth
line of the display that is labeled "VTVM" and a number with
several decimal places that changes so frequently that the LCD
shows a blur with an occasional recognizable digit.? Before I
pack it up and return it, I would like to figure out what is
going on.
Any ideas?? Is there a URL for an explanation of this?
THanks.
Jim K9JEC
--
73, de Vince KD7TWW
In what year did the FCC mandate the 1500 Watt PEP limit for amateur radio station
power output? - Motorola Corp was formally named
"Galvin Manufacturing Corporation" (1928¨C1947)
|
Re: Mic Alternate Choices
I bought on from here:
Took the element out of the housing added it to a 3d printed hand mic and it sounds great.
?
?73
?? David
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Teensy 4.1 Raduino Clone update
#ubitxv6
As of this morning (8/16/2021), it appears that PJRC.com has the Teensy 4.1's back in stock.? I checked Mouser.com as well and they are showing almost 700 in stock (2 different prices for the same Teensy 4.1 - different distributors) so there shouldn't be a shortage of those for a while.
We at TSW recently received new shipments of the PC boards and a re-stock of the resistors, capacitors & hardware used in the kits.? We already had an adequate supply of the Si5351a VFO chips and a backup supply of the Chinese MS5351M version which is electrically and mechanically equivalent to the Si Labs version.?
To be on the safe side, W0EB designed and built a test set specifically to evaluate the Chinese 5351's against the original Si Labs version and could find no real difference in stability or output power between them.? The Chinese ones are also at the same I2C address (0x60) as the original ones so that makes them a seamless replacement if necessary.? The supplier for the Chinese version only ships via DHL so shipping costs are much higher, but in quantity they only cost us about $0.50 US more and that did not increase the cost of the kit enough to pass it along.
All the pricing and ordering information for the Teensy 4.1 Raduino Clone kit is on the TSW website, for anyone interested in purchasing one.
Jim, W0EB
TSW Project Coordinator/Kit Manager
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Re: Nouveau Retro Linear Amp Designs
I have been using the materials on Harry's pages for a long time
73,
Bill KU8H
Sent via smoke signals from my back yard fire pit and a surplus army blanket.
bark less - wag more
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On 8/16/21 11:35 AM, Jim Strohm wrote: All, please note that Harry Lythall SM0VPO is one of the very few sources on the internet who can be trusted unconditionally to provide accurate information all the time.
He also has a very sharp sense of humor.
73
Jim N6OTQ
Sent from my quenched-gap spark transmitter.
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Re: Nouveau Retro Linear Amp Designs
All, please note that Harry Lythall SM0VPO is one of the very few sources on the internet who can be trusted unconditionally to provide accurate information all the time.
He also has a very sharp sense of humor.
73
Jim N6OTQ
Sent from my quenched-gap spark transmitter.
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Re: Nouveau Retro Linear Amp Designs
On Sun, Aug 15, 2021 at 03:23 PM, Ismo V??n?nen OH2FTG wrote:
released an article about "Cokeloop".
I continue to be amazed. Tom, wb6b
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Re: Nouveau Retro Linear Amp Designs
On Sun, Aug 15, 2021 at 03:23 PM, Ismo V??n?nen OH2FTG wrote:
Harry Lythal, SM0VPO has an article on his site about a butterfly high voltage variable capacitor made from pcb material.
I found the links to this and the plastic "Brillo Pad" capacitor. Interesting site. Tom, wb6b
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Re: Mic Alternate Choices
On Wed, May 26, 2021 at 07:09 PM, Bob Lunsford wrote:
for $32 that is a desk gooseneck mic and sounds great.
A nice looking mic. Looks like the price is now $50 (with shipping). May still be a reasonable price. I kind of like my minimalist mic. ----  ---- Tom, wb6b
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Re: Mic Alternate Choices
Doug, one of used the wrong end.?
Don
km4udx
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Re: Is there a decent BITX40 Schematic that can be read when blown up?
Or print at home as multiple pages, tape them together:
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Re: Is there a decent BITX40 Schematic that can be read when blown up?
Consider taking the file to Office Depot . and having it printed D size. About $3.50.
James
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I wrote this for those with a stock v3, which would have either an FCI or WX brand TDA2822.
>? If your TDA2822 does not have a "WX" marking, it's probably just fine.
There are poorly made clones from other manufacturers that fail about like the WX chips.
If I were designing a receiver from scratch that needed a good linear audio amp
to drive headphones or a small speaker, I would follow the advice here:
? ?????
Cheap.? Low distortion.? Runs over a wide supply voltage range.? Parts available forever.
Good linear audio amp chips that can drive a speaker from 12v are disappearing
because there isn't much of a market.? Most consumer products these days
have class D amps which run the output transistors in switch mode.
This can be very efficient, but can create hash in the radio.
Jerry
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On Sun, Aug 15, 2021 at 12:30 PM, Jerry Gaffke wrote:
If your TDA2822 does not have a "WX" marking, it's probably just fine.
When turning up the volume or using a new speaker, it might be worthwhile
to put a finger on the TDA2822 and see if it's getting uncomfortably hot.
And don't go much above 12v into the rig.
Otherwise, go find something else to worry about.
The TDA2822 is only used on the v3 uBitx.
Jerry
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Re: Nouveau Retro Linear Amp Designs
Speaking of retro, here is an old time film explaining the concepts of ohms law and capacitance with what must have been familiar in the day; Cue sticks, pool tables, billiard balls and automobile tires.?
I cringe when I see the brave soul handling the alligator clips attached to an 800v power supply while charging capacitors. Is that why they seemed to switch to a new person doing the demonstrations halfway in the segment??
I love that "big screen" oscilloscope they have.
Tom, wb6b
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Re: Nouveau Retro Linear Amp Designs
On Sun, Aug 15, 2021 at 03:23 PM, Ismo V??n?nen OH2FTG wrote:
was the "brillo pad cap"
The idea of a brillo pad dielectric along with the links to such things as the syringe antenna tuner are truly amazing. Tom, wb6b
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Re: Nouveau Retro Linear Amp Designs
On Sun, Aug 15, 2021 at 03:19 PM, Arv Evans wrote:
With today's CNC mills and 3D printing it should be possible to turn out
price-competitive RF capacitors relatively quickly.
Yes, the advent of the 3D printers and low cost CNC mills sees to have sparked a resurgence of interest in DIY mechanical construction projects. So, the new makers may be very interested in applying new technology along with mechanical construction solutions. And I do hope they keep radio experimenting alive. Tom, wb6b
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Re: Nouveau Retro Linear Amp Designs
Harry Lythal, SM0VPO has an article on his site about a butterfly high voltage variable capacitor made from pcb material.
I'm unsure how good they would be with the dielectric losses of FR-4 with hIgh powers.
One other interesting construction by SM0VPO was the "brillo pad cap", which was like a compression trimmer, except large and with a sponge as a compressible dielectric between the capacitor plates.
I do wonder about the dielectric losses in coax cable as capacitors in loop antennas.
Friemds have successfully burned up coax cqble capacitors made from RG213 cable when running 100w into their homebrew loop antennas.
The maker of Alexloop bramd of magnetic loop antennas also released an article about "Cokeloop". Which used coce cams to make variable piston capacitors. Really neat construction.
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Re: Nouveau Retro Linear Amp Designs
Tom WB6B
Several years ago I embarked on studying the possibility of making DIY
capacitors of the fixed and variable type.? This is where I became familiar
with making a standard size plate capacitor that could be used to determine
capacitance, and from that the dielectric factor of various readily available
materials.? The on-line tables will get you close, but for junk-box dielectrics
I found that I really needed to make reference capacitors to calibrate how
much capacitance to expect from a 2 inch by 2 inch set of plates and various
dielectric materials.?
Variable capacitors can be made with ball bearings, but shafts with
cove-shaped metal-to-metal bearing surfaces seem to be quieter and will
hold their position better than the ball bearing type.? The shafts can be
spring-loaded to keep them centered.
With today's CNC mills and 3D printing it should be possible to turn out
price-competitive RF capacitors relatively quickly.? Might even be a good
side-business for someone much younger than me.? This assumes that
the younger generation keeps ham radio alive and has at least as much
curiosity as us old timers did in our younger years.
Arv? K7HKL
_._
On Sun, Aug 15, 2021 at 4:02 PM Tom, wb6b < wb6b@...> wrote: On Sun, Aug 15, 2021 at 09:55 AM, Arv Evans wrote:
?
?
?
Hi Art,
Those are very good dielectric constant resources, thanks.
In poking around some more after checking out your links, I finally found a couple of tables with loss measurements of a limited number dielectric materials.
Seems the preferred measurement is called "Loss Tangent". The value it seems, only needs to reach a remarkably small number to become an issue.
Here is a short little summary article about capacitors, ESR, Loss Tangent and Q factor.?
Seems capacitors, when you look closer at them, have almost as much intrigue?as inductors with additional factors that pile on to the "ideal" depiction to change their actual performance. At least capacitors, in most cases, can be categorized into broad types that work best in various conditions. Always seems to be a more tenuous?balancing act with inductors.?
And just for fun, this table shows, oddly, that unsalted butter is lossier than salted butter.
Tom, wb6b
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Re: Nouveau Retro Linear Amp Designs
On Sun, Aug 15, 2021 at 09:55 AM, Arv Evans wrote:
?
?
?
Hi Art, Those are very good dielectric constant resources, thanks. In poking around some more after checking out your links, I finally found a couple of tables with loss measurements of a limited number dielectric materials. Seems the preferred measurement is called "Loss Tangent". The value it seems, only needs to reach a remarkably small number to become an issue. Here is a short little summary article about capacitors, ESR, Loss Tangent and Q factor.? Seems capacitors, when you look closer at them, have almost as much intrigue?as inductors with additional factors that pile on to the "ideal" depiction to change their actual performance. At least capacitors, in most cases, can be categorized into broad types that work best in various conditions. Always seems to be a more tenuous?balancing act with inductors.? And just for fun, this table shows, oddly, that unsalted butter is lossier than salted butter. Tom, wb6b
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vince kd7tww
N8DAH
Jim Sheldon
Ismo V??n?nen OH2FTG