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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
By Donald H Locker · #99899 ·
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
By wn4isx <wn4isx@...> · #99898 ·
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
By john23 · #99896 ·
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
By wn4isx <wn4isx@...> · #99895 ·
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
By wn4isx <wn4isx@...> · #99894 ·
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 · #99893 ·
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
By john23 · #99892 ·
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.?
By Andy · #99891 ·
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
By Andy · #99890 ·
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
By john23 · #99889 ·
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 · #99888 ·
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
By wn4isx <wn4isx@...> · #99887 ·
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
By Bertho · #99886 ·
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
By Bertho · #99885 ·
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 · #99884 ·
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
By wn4isx <wn4isx@...> · #99883 ·
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
By wn4isx <wn4isx@...> · #99882 ·
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
By Bertho · #99881 ·
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
By Bertho · #99880 ·
Re: Some comments on SDR radios and control software
What do you want to listen to? I might be able to offer some advice.
By wn4isx <wn4isx@...> · #99879 ·