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Re: Some comments on SDR radios and control software
wn4isx
I was going through a cluttered computer subdirectory and found the original program SDRplay used as the basis for their SDRuno software.
Studio1 was developed by one of the design team for the Perseus SDR.
The developer left the Perseus team and released Studio 1.
Studio1 is available at
I downloaded?
"SDR-Radio V3.3, 64-bit, 2024-02-05_0741"
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The program needs 5 CC+ [or whatever] on my test machine from Microsloth.
It has some very nice features, it might be worth checking out if you like experimenting.
Now to restore this PC to the pre-install version.
I use Macrium backup software as my uninstalller. I simply reboot to the backup software and pick the image that was in use before installing test software. Macrium is (or at least was) free. these things change on a random basis and there are many other fine free disk imaging and recovery packages out there.
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Re: How do you measure really high voltage...like for a spark plug.
wn4isx
Too bad this isn't 1960 and the Ed Sullivan show was on Sunday nights because the presenter is a much better comedian then engineer. His escapades would go over quite well with dancing bears and guys who spin plates on poles. ? However, he'd be tossed out of, and banned, from any university electronics laboratory for his foolishness. ? Suggesting using a resistor divider to reduce direct AC mains to feed a microcontroller is downright stupid verging on criminal. ? The way you measure ultra high DC voltages is with a electrostatic voltmeter. ? https://en.wikipedia.org/wiki/Electrostatic_voltmeter ? I bought a ESH model 600085 at a surplus sale for $5 that will measure 5, 10, 15, or, 20kV. Other then testing it in a real electronics lab, I've only used it once to measure the high voltage for an night scope (starlight scope) tube power supply. ? However for measuring the ignition voltage for anything other then a model airplane engine, which uses a 1.5V glow plug, one needs something like either the?gizmo made from plastic with a screw adjustable gap to measure the ignition/spark voltage, however this measures the voltage under "no load." ? Or the Leslie unit I mentioned earlier which actually shows you how strong the arc is with the engine running. ? When the cylinder rises during the power stroke, the 'air' pressure increases, if you have an engine with 10:1 compression, then your pressure when the spark occurs would be 10 X 14PSI, 140PSI. 140PSI = ~ 7240 torr. see the graphic at http://www.highvoltageconnection.com/images/paschen-curve_clip_image002.jpg ? The chart maxes out at 720 torr and shows the voltage required to be in excess of 70,000V. [I have doubts about this graph but don't feel like working out the math this morning.] ? Wiki goes into Paschen's law in quite a bit of detail. https://en.wikipedia.org/wiki/Paschen%27s_law ? All of this is interesting from a theoretical angle, but the practical aspect is simple: ? "Just because your ignition system produces a spark/arc in a spark plug outside the engine does not mean it will produce a spark in the engine under compression." ? I've seen this in Honda CB350s, 1968 and 1969 stock VW bugs. The ignition coils in the Honda twins was located where they were heated by the engine, I never had a hard failure but I could tell when it was time to replace one when the power dropped way off and the engine sounded funny, both ignition coils never failed at the same time so the power was really imbalanced between the cylinders. I limped home from Mason Ohio [near Kings Island] to Lexington one night sweating "Will I make it home...." ? VW coils just failed for the fun of it. West German manufacture wasn't quite as perfect as they'd have liked for you to believe. ? I learned more about ignition systems then I wanted with those vehicles. I've never had an ignition coil/system fail in Chevy Nova [My wife's when she was my girl friend. Car died when someone t-boned it in a parking lot. Bummer] Subaru [two cars, 1980 station wagon, 1984 compact] VW transporter van with Porsche engine [I have no idea why a very similar engine never experienced a fuel pump failure or ignition coil failure.] Toyota [3 cars] Ford [1 car we put over 200K miles on.] ? I did have the ignition coil fail on a Plymath Omni, about a month before the engine decided to emulate a grenade. [Way too exciting at 80MPH on the Mountain Parkway at 3:00AM. You've never lived until you have parts of the engine come through the hood right before your windshield is covered in oil and coolant. Loads of unfun.] ? ? [I always carried a spare fuel filter, fuel pump and ignition coil. <and fan/generator/ belt> for the VWs. I've changed the fuel pump and ignition coil by feel in pitch black dark out in the boonies more times than I care to remember. Yea for a person who collects flashlights it was silly not to have one, but the batteries were always dead when I needed the light. I finally got smart and made a 12V trouble light with 20 feet of wire, a fuse and power port to the battery and never had a fuel pump or ignition coil go bad again.] ? A dying ignition coil can produce what appears to be a very strong arc in a spark plug outside the engine and not work or sort of work in the engine. ? Sort of work to mean, rough idle, stalls when you give it gas. ? Modern automotive/light truck ignition coils are extremely reliable. ? Briggs and Stratton lawn mower ignition coils not so much..... ? ------------------- Real mechanics with real garages with real test equipment designed for cars often have specialized oscilloscopes that will display the ignition voltage. It's worthwhile getting a glimpse if you have a friendly mechanic. ? I would never consider trying to build an adaptor to allow me to see the ignition voltage waveform on my DSO. One could probably salvage the ultra high resistance resistors from cold war civil defense ion chambers and add plenty of diode protection clamps but I'll let others fry their DSO when the Leslie ~$20 device works very well. ? BTW I have no business relationship with Leslie, I'm just a very satisfied customer. ? For the really brave...[or foolish]
? I have no idea if the device will work or fry your scope. ? Ya pays your money and takes your chances. [not me.] ? Oh changing the two drive belts was amazingly easy, took two hours, mainly because I removed the pulies and lubricated them [one bearing will need replacing sooner then later, it's on order] and cleaned the space under the deck, used a wire brush to remove some rust and painted it with a high quality epoxy paint, and I blew dead grass bits out of 'everywhere.' I also added a kill switch to the seat, get out and the engine shuts down. The twins are a bit careless. I do not want anyone to lose a foot. [Yea I'm paranoid.] ? ? ----------------------------- |
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Re: How do you measure really high voltage...like for a spark plug.
开云体育1 - the Freon also provided insulation for the voltage divider
resistors. When the Freon eventually leaked away, you could see
the corona on the internal connections. 2 - the polarity of the spark (at compression pressures) makes a huge difference. Driving the center electrode (which is much hotter than the side electrode) negative saved a couple thousand volts. The wasted spark doesn't need very much voltage - something on the order of a few hundred volts - or take very much from the working spark because it's firing into exhaust gases, which are already hot and ionised, and at a quite low pressure (slightly above atmospheric). 3 - The Leslie spark indicator (or something like it) is old, but
effective, technology. My dad's timing light was basically a
housing with a lens holding a neon lamp that went in series with
plug #1. Donald. On 3/22/25 05:51, wn4isx via groups.io
wrote:
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Re: How do you measure really high voltage...like for a spark plug.
wn4isx
A potential problem is the voltage also has to have enough current when the cylinder is at the top of the compression cycle and a voltage reading under "no load" might not indicate the voltage when the spark plug is under maximum compression.
The Leslie unit actually indicates voltage/current flow through the spark plug via the arc.
Proper high voltage will make the neon bulb light up rather brilliantly, weak high voltage/current will give a very weak light output.
I considered the style indicator you suggested but a mechanic told me to spend a bit more for an indicator that actually shows you what is going on.
The Leslie costs about $20 and worked very well for our needs.
Most modern vehicle ignition systems have "coil packs" per spark plug or for two spark plugs.
The later doesn't ground the one end of the high voltage winding, it is double ended and feeds one output to one spark plug and the other output to the adjacent plug. This was more common in the 1995~2010 time frame or with inexpensive [cheap] cars today.
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My wife's 1998 Ford Escort ZX2 used this scheme and called the spark in the non firing cylinder a 'waste spark.' I can post a diagram of the spark plug wiring scheme in the files section if there is any interest.
While we got rid of her car when the rear end rusted out, I found I didn't quite delete all the service data like I thought I had.?
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I always wondered, still do, what effect the "wrong" polarity voltage on the spark plug tip will have.
Based on what I learned in a physics class a lifetime ago, you'd want the center terminal of the spark plug to be positive because it will arc at a lower voltage.
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But the ZX2 had plenty of horsepower, really way overpowered for the weight of the car, it'd get away from you if you had a heavy foot on take off. The cops in central Kentucky love to write tickets for "improper acceleration" and if you lay rubber or scratch off around a cop, you will get a ticket. I always had to be extra careful to use a light foot when driving her car. And driving that car in snow was an interesting experience.?
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So the ignition system in the ZX2 had more then enough voltage/current to fire even a negative center terminal spark plug.
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I saw the spark plugs in another ZX2 that hadn't been changed since the car was new, the ground electrode had been eaten away by 280K miles of "sparks" and the car still ran fine. The center terminal was also eaten back but not near as bad. Frankly if you'd shown me the spark plugs I'd have bet the engine they came from would not run. The ceramic cone looked nice and grey like they are supposed to. Replacing the plugs didn't make any noticeable difference in performance horsepower wise, but did improve gas mileage about 10%.
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So I guess the ZX2 had plenty of high voltage.
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Back in the late 1960s Champaign offered an odd plug with no bent over ground element. The spark traveled directly across a ceramic plate. My father tried them in his Chrysler Valiant. They seemed to work OK.?
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To check polarity of voltage feeding center element of spark plug
"use a soft graphite pencil (the softer the better) sharpened to a fine point. Disconnect a spark plug lead and remove the resistor plug cap so you have the bare HT lead conductor exposed. Hold the end of the lead close enough to the cylinder head for a spark to jump. Put the tip of your graphite pencil in between the lead and the head. Now with your 3rd and 4th hands (you will need helper) switch off the workshop lights and crank the engine. A spark will jump from the lead to the engine via the graphite pencil. In the darkened room, you should be able to see a flare (of ionised graphite) from the pencil tip. If the flare is toward the cylinder it indicates correct polarity. A flare toward the HT lead indicates reverse polarity."
From https://laverdaforum.com/threads/coil-and-spark-plug-polarity.92932/#
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He notes that with the one ignition pack for two spark plugs one will be fed reverse polarity.
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Enter "what effect does pressure have on an electrical arc?" into Google and the AI bot has a nicely detailed explanation of the relationship between air pressure and the voltage to strike an arc.
I'd enter the direct link but is way too long and unwieldy and you can'c chop any of it out.
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Most gasoline engines have at least a 6:1 compression, most car engines probably have 8:1 and motorcycles have up to 12:1 for high performance "donor cycles." The Honda CB/C: 250/350 had a compression ratio of 9.3:1, the higher the compression ratio the higher the octane required. That's why racing motorcycles often use aviation gas...it has a much higher octane.
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Thus ends today's lesson on ignition systems, which I'm sure bored everyone to tears.
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Re: How do you measure really high voltage...like for a spark plug.
开云体育Hey guys,
I’m not sure after all this time if the group rules allow posting links to Amazon site. ?So I’ll just tell you to go to Amazon and search for “spark plug voltage tester”. ? You basically place this device online with the coil and ground. ?There’s
an adjustable gap. ?Higher spark voltage will jump bigger gap.
It’s not exact / precise but it works well enough for car spark voltage testing.
?= ?= ?= ?= ?= ?=?
If I’m not mistaken spark plug voltage isn’t like battery voltage. ?The voltage builds up until the spark can jump the gap. ?I’m not sure if you were to actually measure spark plug coil voltage, that’s not the same as the voltage when the spark
actually jumps.
Jong?
On Mar 21, 2025, at 3:54 PM, wn4isx via groups.io <wn4isx@...> wrote:
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Re: How do you measure really high voltage...like for a spark plug.
wn4isx
Somehow the idea of using a HV probe that requires Freon cooling is a bit beyond the pale even for me!
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My Bird Termaline Watt Meter is rated at 60W, I mounted 2 4" 120V muffin fans against the heat sink and I've ran 150W into and it didn't die, didn't even get hot enough to smell oil.
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But a HV probe that requires Freon cooling gives me the willies.
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And I bet the Leslie probe cost a whole lot less then the Tektronix probe, even if it doesn't display the waveform out to 100MHz or so.
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Sir you've worked with some very exotic equipment!
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Re: How do you measure really high voltage...like for a spark plug.
开云体育Back when I was doing automotive ignition system system
development, we used a Tektronix HV probe, quite similar to
It required a Freon charge inside the forward plastic housing (I
believe to cool the dropping resistors) and was finicky to use. Donald. On 3/20/25 21:05, wn4isx via groups.io
wrote:
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Re: Replacing memory back up cells with a super capacitor
wn4isx
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 lot higher leakage and be totally unsuited for memory backup.
I have no way of checking this possibility but thought I'd toss it out to warn people what worked extremely well for me might not work for them.
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I just powered up an iCom IC-28A that has not been powered up for at least 6 years. All the memories were there. I'm preparing for a very active severe storm season and our landlords are studying for their amatuer lisences. My wife, the twins, and I want reliable communication in the event of tornadoes.
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I also wanted to open one modified IC-28A to verify how I did it so I can modified 3 others.? ?
The memory cells in all 3 'new' IC-28A are dead.?
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The IC-28A is an older single band transceiver, kind of obsolete to most hams. I don't need 70cm and I got a good deal on these units, $20 each. They were barely used, mainly to monitor several local repeaters.
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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 circuit, also I was given the following advice? but I cant imagine how to draw it.
Could you please reccomend me a cool circuit?
Thanks. "You can proceed with an Op-Amp (LM358), an NTC thermistor,? a MOSFET (IRF540) and a resistive heater (10W).
?The op-amp will compare the thermistor voltage to a reference voltage. If the temperature deviates, it will switch the MOSFET on/off to regulate heating." |
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Replacing memory back up cells with a super capacitor
wn4isx
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 the receivers have a 5V rail, I used a 4 1N914 or 1n4148 small signal silicon diodes between the 5V rail and positive of the super capacitor to drop the voltage. The nominal voltage drop of a silicon diode is 0.7V, however under extremely low current this can drop to as low as 0.5V. It will vary from diode to diode even in the same family. I also included a 100 ohm resistor just in case, I like to always have current limiting. The V+ of the super capacitor was connected directly to the V+ memory backup. In my first installation I did things a bit different. I used a 1K resistor from V+ 5V to a string of 1n4148 diodes to give a "regulated" V+ between 2.5V to 2.9V. Memory keep alive in the R-2000 is 2V. ? I adopted the first version I described after some thought and experimentation with a R-2000 with a defective tuner optical pulse decoder on the main PCB that defied repair. ? You can tune the radio, it's just a royal PITA that can take an hour to tune to the desired frequency. I programmed in useful frequencies in all 10 channels and treat the radio as a fix tuned radio. I have WWV on 2.5/5/10/15, CHU on 7.850, and, US Global HF Network 4.7240, 8992.0 11.1750, 15.0160 and 11.2320 [interoperations with Canadian forces]. ? My super capacitors came from the factory keep alive PCB in Kenwood commercial radios, these PCBs were removed and trash after the PCB with all the programmed channels was installed. ? I've modified 10 Kenwood R-2000 general coverage receivers and 2 iCom IC-28A 2M amateur transceivers. I'll be modifying 3 more IC-28A in the near future. ? My super capacitors are 30 years old and are 4.?F, One R-2000 was not powered up for at least 4 years, probably 5 and half, all the memory channels were still there. Modern higher value super capacitors might have higher internal leakage. I've ordered some 100F 3V supercaps to experiment with. ? Supercapacitors have odd chemistry and I suspect they will last longer if they are kept biased at their operating voltage. I was given about 30 of the Kenwood keep alive boards, pulled the supercapacitors and they are on a 3V rail powered by my primary 12V ham radio power rail. They've probably been without power for maybe a week since I wired them to the 3V rail. My experience with the R-2000 that was powered off for at least 4 years suggests the chemistry is more robust then I initially suspected, but, the supercapacitors are in a dedicated plastic box and I see no reason to remove them from the power. [I'm too lazy to change some things without a good reason.] ? All of this came about because I couldn't find a replacement battery in Lexington and didn't want to wait for mail order, well that plus the memory back up cell in the R-2000 is soldered in, which means you have to remove all the very flimsy (cheap) connectors. ? I was initially going to mount a 2 AA battery holder on the rear of the R-2000 when I was given the Kenwood "keep alive" PCBs and decided to give a crazy idea a try. ? YMMV ? ? |
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How do you measure really high voltage...like for a spark plug.
wn4isx
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 of identical twins who love yardwork (as far as I'm concerned you could cover the front and back yards out to 50 feet from our home with a foot of small gravel and spray with an herbicide at regular intervals.) ? I did all the normal checks. The fuel was drained at the end of the season, from the fuel tank and carburetor bowl, the engine ran with fogging oil and the air filter cleaned, then the riding mower was placed in the detached garage. ? For the new season, the tires were checked and topped off, a new spark plug was installed, good gas used to fill the tank. ? The battery was on a float charger all winter. Turning the key to start caused the starter to crank with normal speed but no joy, not even a backfire. I used some ether (I'm lazy) and got a feeble backfire. ? Testing with a spark plug showed an arc the gap, but, at peak compression it takes a lot more voltage for the arc to form, how much more voltage, I'm not sure. But a mechanic told me "Up to 4 times." ? OK how on earth do I measure up to 20kV? ? The Leslie Corporation offers a nifty inline tester with a neon bulb with terminals on each end. The tester goes in series between the ignition coil output and spark plug hot terminal. If good, as in adequate, high voltage is present, the neon bulb will flash pretty brilliantly, if the high voltage is low, there might be a dim glow. The Leslie 20610 INLINE SPARK TESTER is available at Advance Auto or online. I went with Advance Auto because we decided time was more valuable then a few dollars. It was money well spent. ? Changed the ignition coil, PITA to get to, and presto, our landlords think I'm a genius. [Ha do I have them fooled or what?] ? We also used compressed air to blow debris out of the ventilation fins on the flywheel and generally clean the engine. ? ? The engine started instantly and ran perfectly. Looking back it is clear the ignition coil was dying over the last 2 or 3 summers because the engine runs smoother with a LOT more power. ? Our next joyful task will be to change the drive belts. They are a little frayed and I feel it's a lot better to change them when it's 50 then 90 with 80% RH. [Yippee I can't wait.] ? |
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Re: logic of bjt regulator
On Sat, Mar 15, 2025 at 05:00 AM, john23 wrote:
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 two bases drive the collector currents, and thus, the voltage on node 1.
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The PNP transistor further amplifies the voltage on node 1.? When that voltage drops lower than +14.3V, the PNP turns "on" harder and passes more collector current towards the load.
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In operation, it is a feedback circuit that drives the output (node 3) until it roughly equals the voltage at the left NPN's base.? If it drops below +2 V, the left NPN conducts more collector current, node 1's voltage falls, the PNP turns "ON" harder, and sends more current to the load - as needed, to pull that voltage back up.? Hence, it regulates it at about +2 V.
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Andy
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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 will be translated to the other PNP base. Could you describe how the regulating dinamics works here? Thanks. https://www.youtube.com/watch?v=nOOOAjoqCt8&list=PL4C141B35706AD19A&index=3
/g/electronics101/photo/296358/3896088?p=Created%2C%2C%2C20%2C2%2C0%2C0 |
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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.? Motorcycle headlights lack that clue.? So the auto driver thinks it is very far away and there is plenty of space to turn. ?
Headlamp brightness probably would not help.? It still looks far away.
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In daylight, I suspect many auto drivers (instinctively?) think motorcycles can't be as fast as or faster than their auto, so certainly there must be plenty of time.? ?Even if the motorcycle gets cut off, they are small and can stop fast - right?? The driver might not THINK this, but it is what their brains are telling them.
I think auto drivers do not purposely try to get in the way of motorcycles.? We all know they are death traps, a surely unsafe way to go down the highway, so why would anyone want to make it even less safe for them? ?
I lost a cousin just a few years ago, riding his motorcycle home from work.? The intersection where it happened has claimed the lives of several unfortunate souls, yet the city stupidly does nothing to improve it - even when senseless accidents like that happen again and again.? They probably say it is too expensive to mark it better.? Shows you how little they value a person's life.
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Andy
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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 -
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On Thu, Mar 13, 2025 at 06:11 AM, john23 wrote:
I am unsure how to interpret "1Kelvin". ?
Do you mean that the device should continue to work down to a minimum temperature of 1 K (1Kelvin)?
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Or do you mean that the device's precision should be 1 K?? If this is what you meant, then I think 1°C is an equivalent amount of precision, because a temperature change of 1°C and 1 K are equivalent.? Do you agree?
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Andy
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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 temprature regultor up to 1Kelvin. Is there some material of a project I could try to learn it? Thanks. |
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Re: Active Antennas
开云体育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 works is way to quickly fire up the SDR. For $12 arriving in two days looks like a good choice.? Being open, it allows me to see the design.? I obviously need to add a simple enclosure. I have lightning rods on my home, so I plan to attach the antenna to one of them.? I will ground the bottom end of the coax to the buried ground system. That reminds me:? When I built the house, I used 1” regular copper plumbing to run a low impedance ground connection from buried lightning ground system to my workbench. The plumbing inspector had a fit since the pipes were not on the plumbing drawings. Bertho ? From: [email protected] <[email protected]> On Behalf Of wn4isx via groups.io
Sent: 9 March, 2025 12:56 To: [email protected] Subject: Re: [electronics101] 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 worth it it. At my last two jobs I was the unofficial "researcher." ? Glad to help. ? I'd seriously consider breadboarding a stock PA0RDT dead bug style, isolate the 'plate' with a dremal tool. The J310 is easy to locate, the 2N5109 might be a challenge. ? Avoid active antenna designs with MOSFETs as the gate capacitance will kill the incoming RF. This can be avoided but it gets way too complex for the performance of the antenna. ? This is another resource, I've built the antennas using 6CW4, I used 13CW4 because I had them. ? This design works extremely well...OK can't copy the link as it brings up the graphic. Look for the design that uses 3 6CW4s. ? ? |
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Re: Active Antennas
wn4isx
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 worth it it.
At my last two jobs I was the unofficial "researcher."
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Glad to help.
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I'd seriously consider breadboarding a stock PA0RDT dead bug style, isolate the 'plate' with a dremal tool.
The J310 is easy to locate, the 2N5109 might be a challenge.
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Avoid active antenna designs with MOSFETs as the gate capacitance will kill the incoming RF.
This can be avoided but it gets way too complex for the performance of the antenna.
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This is another resource, I've built the antennas using 6CW4, I used 13CW4 because I had them.
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This design works extremely well...OK can't copy the link as it brings up the graphic.
Look for the design that uses 3 6CW4s.
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Bertho