Re: How do you measure really high voltage...like for a spark plug.
Back when I was doing automotive ignition system system development, we used a Tektronix HV probe, quite similar to https://www.bellnw.com/products/tektronix-p6015a It required a Freon charge inside
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Donald H Locker
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#99899
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Re: Replacing memory back up cells with a super capacitor
I had a thought a moment ago, it is entirely possible the Panasonic capacitors Kenwood chose for their factory backup board were designed for ultra low leakage and normal supercapacitors might have a
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wn4isx <wn4isx@...>
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#99898
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Re: analog feedback temprature regulator question
Hello, I ment as precise as possible 1C presition is cool too.
I want to use feedback mechanism to regulate the temperature of a box.
I want to do some fancy analog feedback like PID controller
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john23
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#99896
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Replacing memory back up cells with a super capacitor
We were discussing batteries a few weeks ago and I mentioned I used high value capacitors, AKA super capacitors, to replace the 3V lithium disk cell.
I received an email asking for details.
All of
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wn4isx <wn4isx@...>
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#99895
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How do you measure really high voltage...like for a spark plug.
I ran into a problem Monday, time for the first lawn cutting of the year, trust me, at 73 I don't even use a riding mower because the vibration would kill my artificial knees, our landlords are a set
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wn4isx <wn4isx@...>
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#99894
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Re: logic of bjt regulator
Pull out your analog design books.
This is a feedback loop.? The two NPN transistors are a differential pair.? ?I trust you know how differential pairs work.? The difference voltage between the
By
Andy
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#99893
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logic of bjt regulator
Hello, I am trying to understand the dinamics of the circuit taken from the youtube video.
if we apply 2V DC the node 2 on the photo will be 1.4 (Vbe=0.6)
The node 1 will expirience some voltage wich
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john23
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#99892
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Re: A downright amazingly stupid LED headlight, I'm impressed.
On Fri, Feb 28, 2025 at 11:35 AM, wn4isx wrote this about motorcycles:
I have a theory about that.? Drivers instinctively use the space between oncoming headlights to gauge how far away it is.?
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Andy
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#99891
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Re: analog feedback temprature regulator question
This is just a question about the question you asked, as I am unable to provide information about plans for a differential temperature regulator -
I am unsure how to interpret "1Kelvin".
Do you mean
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Andy
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#99890
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analog feedback temprature regulator question
Hello, I am looking for a differential feedback temprature regulator project which explains the theory best it could and give practical example in simulation.
I am looking to design a very precise
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john23
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#99889
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Re: Active Antennas
Another extensive active antenna link! Thanks! More reading ?
Time allowing, I will build something. Right now, I got to take care of business as a priority so getting something that reasonably
By
Bertho
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#99888
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Re: Active Antennas
While I learned the required subject mator for my two degrees in university, the main thing I learned in university was how to research. It was a bit of a challenge to transition to the web but well
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wn4isx <wn4isx@...>
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#99887
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Re: Active Antennas
Thank you wn4isx!
Your link to Martin G8JNJ's active antenna pdf very extensive:
https://qsl.net/l/lw7dfm/Antenas/Antena%20Mini%20Whip/MARTIN%20-%20G8JNJ%20-
%20Active%20antennas.pdf
More
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Bertho
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#99886
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Re: Active Antennas
I found that one, https://www.pa3fwm.nl/projects/miniwhip/, but I have not found the second part one in the pictures that is discussed with improvements.
I found this one that looks
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Bertho
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#99885
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Re: Active Antennas
After spending too much time searching and reading about active antennas and
building a library, I visited Amazon.
Search for "Mini-Whip Antenna".
There are enclosed ones, but I ordered a promising
By
Bertho
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#99884
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Re: Some comments on SDR radios and control software
Pieter-Tjerk de Boer, PA3FWM has a series of articles on E-Field antennas that can be extremely helpful in getting the best performance from these antennas.
Fundamentals of the MiniWhip
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wn4isx <wn4isx@...>
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#99883
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Re: Active Antennas
Pedid y recibiréis
Simple and better circuit for MiniWhip antennas
https://www.pa3fwm.nl/projects/miniwhip/
The 2SC5551A might be a viable substitute for the 2N5109 in the original PA0RDT
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wn4isx <wn4isx@...>
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#99882
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Re: Some comments on SDR radios and control software
Thanks,
I have no specific plans except testing the new technology and also look at GPS signals.
I did a lot of work with GPS 30 years ago and I still have some active GPS antennas to try.
The
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Bertho
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#99881
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Active Antennas
Previously wn4isx posted a link to: https://www.pa3fwm.nl/projects/miniwhip/
The reference refers to an improved version but there is no link to it.
Does anyone know where I can find the improved
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Bertho
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#99880
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Re: Some comments on SDR radios and control software
What do you want to listen to?
I might be able to offer some advice.
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wn4isx <wn4isx@...>
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#99879
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