My Take on the Carlson Super Probe (Now with scope output!!) - Page 1
Forum section: electronics / projects

author: watchmaker
author_rank: Unknown
timestamp: February 12, 2025, 04:03:43 pm
content: I bought the Hollywood Controls kit as the easy way out. Assembly is not issue, I use a 5X glass magnifier lamp. One transistor flipped into the lost screws dimension. Really should not work on black flooring.Anyway, the issue is how to house the probe circuit board. I looked at the instructables version and the only part that was helpful was the isea of using 3/4 inch copper pipe. But he makes it too complicated.Only 3 pieces are needed. A length of pipe and two endcaps. The issue for some will be drilling the holes in the endcaps and milling the slot. Even then, copper is so damned sticky!Since modern coax uses Al for the shield, I used copper braid soldered to the ckt board ground. I then insulated the body and shield with shrink tubing (may redo the body).I also used the overload lamp and a charge monitor for the battery. Amp is mounted in a box form Ali and I am waiting for the speaker.

author: floobydust
author_rank: Super Contributor
timestamp: February 12, 2025, 05:02:43 pm
content: It's still a bear to package one of these. It's gotta be metal for shielding and Mr. Carlson should have taken it to the next level and got an enclosure for it other than a cigar tube.You can also look at hobby storei.e. K&Sbrass tubing and channels, you can solder that and make a rigid coax end.You might know but it is possible to pick up a watch's quartz crystal oscillator with the probe near the module (open case).I thought it is usually an inductive pickup coil used for 32.768kHz but I'm not in the business. You could try a pickup coil on the Super Probe should work, for when tuning it.

author: MarkL
author_rank: Unknown
timestamp: February 12, 2025, 09:16:29 pm
content: Quote from: floobydust on February 12, 2025, 05:02:43 pmI think he actually gutted an old Heathkit RF probe, which is how he got the nice end-caps.

author: watchmaker
author_rank: Unknown
timestamp: February 13, 2025, 02:48:21 pm
content: Quote from: floobydust on February 12, 2025, 05:02:43 pmHas anyone put a scope lead from this (I am thinking a cutoff probe)? Where would I pick up? Probe output or at the amp output? (I am assuming I would have more bandwidth at the probe?) I guess nothing beats failure but a failure to try.Also, why does Carlson ground his probe case to the ckt under test? If beneficial, I will run a ground wire from the amp box and not have it hanging off the probe.I'll tell you about quartz. We had a 4-day short course during my training. The "kids" all told me how easy it was to make $125 for 30 minutes of work. I have hated quartz since day one.So anyway, we progressed from time only to the chronos. I handed my chrono back in pieces despite the fact that I do minute repeaters. Good thing this short course did not count toward our marks!

author: RoGeorge
author_rank: Super Contributor
timestamp: February 13, 2025, 03:18:57 pm
content: Quote from: watchmaker on February 12, 2025, 04:03:43 pmSweeping the floor area with a large magnet might bring back many of the lost items.

author: MisterHeadache
author_rank: Regular Contributor
timestamp: February 13, 2025, 09:26:11 pm
content: I built my version using a length of 35mm OD aluminum tubing that I bought off of Amazon. I then designed and 3D printed my own end caps. The aluminum is a lot easier to drill and cut than copper, it is a bit gummy still though.

author: RoGeorge
author_rank: Super Contributor
timestamp: February 14, 2025, 02:36:33 am
content: Didn't know what such a probe is/does, so I've watched an assembling + demo video, with a screwdriver touching a metal plate demonstration at the end. Mr Carlson said he can talk for hours about what other uses such a probe might have, yet he didn't. Scratching a metal plate with a metal screwdriver can be easily heard with any AM radio.My question is, what is the probe for? Or, how does it helps when debugging something? Is it really helpful?I would like to see more examples of how to use the probe in practice.

author: alpher
author_rank: Frequent Contributor
timestamp: February 14, 2025, 04:01:49 am
content: https://youtu.be/uVkJqqZroN0?si=gqVh9xFoWyqzHadh

author: shabaz
author_rank: Frequent Contributor
timestamp: February 14, 2025, 04:58:28 am
content: Long story short: It's an insulated probe connected to a speaker, and to an LED. Internally it's several cascaded BJT amplifier stages with a high-impedance input so that any nearby signal (typically from a radio or whatever) is simply coupled at close proximity, like an electric field probe.It allows you to move the insulated probe end around close to components on a powered-up circuit-under-test, and audibly listen to what gets picked up.There's also a switch to turn on a sort of comparator so that any high excursion signal can flicker an LED and cause clicks on the audio output (i.e., it's a kind of crackle detector, say if there's a dodgy wire connection in the circuit-under-test).It's like an alternative to the old-school "test audio amplifier" that used to be seen on TV repair shop benches (Radio Shack used to sell a little battery-powered one based one an LM386, that had the high gain that the LM386 can be easily set to, and could be used to listen to signals on a board at a pinch.I used to use a $1 crystal earpiece, when I was a kid and didn't have a 'scope or any other tool. And then bought the Radio Shack LM386 amp at some point, lost years ago. I didn't use it for repairing anything, just more for curiosity about what could be picked up.(Radio Shack schematic source: Google Images).

author: floobydust
author_rank: Super Contributor
timestamp: February 14, 2025, 10:15:43 pm
content: Quote from: RoGeorge on February 14, 2025, 02:36:33 amMr. Carlson Super Probe is extremely high gain, at least 100-120dB! The transistor stages plus the LM4871.Basically a contactless-probe (capacitive E-field) audio amplifier along with a "noise" or AM detector so you can hear AM as well.Uses include signal tracing RF/IF/AF stages, wire tracing, QRP, sniffing EMI/RFI.It's got many real uses, once you realize a scope is not the end all be all.Quote from: shabaz on February 14, 2025, 04:58:28 amRadio Shack Mini Speaker Amplifier goes back to 1968, first incarnation used four Ge transistors. Many revisions, A,B,C.The 277-1008Btransistor gain x10, LM386 gain x200 for x2000 or 66dB overall. A 1mV input delivers 2V to the speaker.But it's a fail... because the input impedance (potentiometer) is only 5kΩ.There are at least three revisions to the 277-1008, I remember it was paired with a telephone-bug inductive pickup back in the day, later for the CoCo, TRS-80, Sinclair for sound.Used as an electronic stethoscope for picking locks on vaults, harmonica (crystal) microphone 33-115 for input and headphones.Used as final speaker amp for ELF-VLF magnetosphere recordings.

author: shabaz
author_rank: Frequent Contributor
timestamp: February 14, 2025, 10:29:30 pm
content: Quote from: floobydust on February 14, 2025, 10:15:43 pmIndeed.. back then I wouldn't have known the reason, but later realized that despite loading the circuit-under-test somewhat, that very high gain often would still allow a signal to be heard. Any circuit I wasn't able to hear, I'd have attributed to construction failure by me.QuoteIt was a very useful amp! I remember seeing that pickup coil for it. Pocket money only allowed a few small purchases occasionally however.

author: watchmaker
author_rank: Unknown
timestamp: February 15, 2025, 12:31:01 am
content: Quote from: RoGeorge on February 14, 2025, 02:36:33 amI think it will (and has) prove useful. Just for kicks, I picked up the 1kHz signal from my siglent signal generator. The BNC shield works great; put the probe in the cneter and buzzzz.I also just got a messy Sencore MX129 to play with. I will be posting about it in the repair section; need advice on how to test an ECG 160 equivalent (4 leads).But when I unpacked the unit I listened to it with the probe and confirmed it generates 60 and 1000 hz signals and was able to trace down working sections.So I like the Carlson Probe.See my post on my repair attempt in repairs. Will likely take a couple days.

author: profdc9
author_rank: Frequent Contributor
timestamp: February 15, 2025, 01:39:34 am
content: I made a PCB with a Carlson Super Probe and it can be populated by JLCPCBhttps://github.com/profdc9/SuperProbe/It's a single PCB with a solid ground plane. I have used it to demonstrate EMI/RFI.

author: watchmaker
author_rank: Unknown
timestamp: February 16, 2025, 12:15:39 am
content: My finsihed probe set. Ground wire is attached to the phone jack in the back. 3.7Lipo withe charge monitor. I had an extra hole so I stuck a coax in it to see later if it makes senses to hook it up to the scope.My sweetheart did the labelling for me.

author: RoGeorge
author_rank: Super Contributor
timestamp: February 16, 2025, 03:20:38 am
content: Nice build!(Funny aspect, to me that looks very patriotic, because red-yellow-blue is also the flag of my country, Romania.)

author: floobydust
author_rank: Super Contributor
timestamp: February 16, 2025, 03:57:56 am
content: The enclosure looks really niceshould be fun use.For other Super Probe builders, I see metal cigar tubes onAliexpressand had to laugh they (cigars) come in standard gauge sizes.Another use for the super probe is a spy bug detector. It is basically an all-band receiver. WentzelThe Amazing All-Band Receiverhas more info, and I haven't tried adding a LF local oscillator like the old russianSinitsa.Not that I'm snooping for eavesdropping devices, like I say anything interesting lol, it's for finding subtle quirks in circuits like spurious oscillations.

author: watchmaker
author_rank: Unknown
timestamp: February 19, 2025, 01:34:46 am
content: Here is my box layout. But more importantly, connecting a scope output to the Probe input to the Amplifier works.1 MHz from the generator, probe head set to RF. 1 MHz on the scope. This is starting to get interesting.

author: shabaz
author_rank: Frequent Contributor
timestamp: February 19, 2025, 04:28:11 am
content: What you've got there is what's known as an e-field probe (but with quite a lot of distortion, which doesn't matter when just listening to it, or when viewing on a 'scope provided you're aware of it); you can buy such probes, but normally they are expensive.There are some DIY e-field probe projects, often with slightly complex construction for the amplification, which is used (it's the nature of the beast for high-frequency response).Another idea is to just use a piece of coax, with a couple of millimeters of center conductor exposed at one end. It won't be very sensitive, but that's the beauty of owning a 12-bit 'scope, you'll still be able to see some results (although, you'd probably need to switch to spectrum mode, that will be more effective with the probe, and experiment with settings).The attached photo shows a home-made e-field probe, and example output from it (I tried to set up the same conditions as you, i.e. 1 MHz, 4Vp-p (this is quite a large signal! you could try reducing it, to see if the distortion is lessened), and I just rested the probe near the output lead same as you. As you can see, I have a bit of distortion present as well, harder to tell from the time-domain view because that still looks sinusoidal. My probe was a bit of a failure, I was aiming for 1 GHz but it only works up to about 350 MHz (fairly flat to 250 MHz), whereas a lot of DIY projects can achieve 1 GHz and beyond. I have not got around to trying any DIY e-field probe project on the 'net so I can't comment on what would be worth assembling or not; others will know better.

author: watchmaker
author_rank: Unknown
timestamp: February 19, 2025, 05:15:59 pm
content: Thanks. I have much to learn about interpreting scope traces.The limit appears to be around 2MHz at 2 Vp-p.Noobie error. Turns out the limit appears to be 24MHz.Might try disconnecting the probe input from the amp with a switch.

author: shabaz
author_rank: Frequent Contributor
timestamp: February 21, 2025, 04:19:08 am
content: 24 MHz is quite reasonable, more that I'd expected; certainly useful for even probing around microcontroller clocks and I/O.QuoteIt's a good opportunity to explore the spectrum view on your 'scope, because I suspect (I don't own the instrument) that your 'scope will be quite good for working with the probe. You'd need to experiment a bit to see how to get the output speedy/responsive enough for probing around on a board.If supported, I'd suggest starting with (say) 10 kHz to 100 MHz span, set to Logarithmic frequency mode, and(if it's possible to configure, set RBW to 10 kHz as initial starting settings), that should provide a nice clear range for exploring all sorts of circuits with the 24 MHz capable probe, at a reasonable speed.Placing the probe near a crystal oscillator on (say) an Arduino board or other convenient board to experiment with, will become visible and easy to read off on the spectrum view. If responsive enough settings are found, then the normal time-domain 'scope trace will become less relevant, it can be reduced/minimized while using the spectrum view with the probe (it will feel weird initially for sure, not placing your primary focus on the time-domain view on a 'scope).

author: watchmaker
author_rank: Unknown
timestamp: February 24, 2025, 02:54:55 pm
content: Quote from: shabaz on February 21, 2025, 04:19:08 amThank you. I printed this out and will play with it. Right now I have gone back to elanring my fundamentals via Real Analog.

author: MathWizard
author_rank: Super Contributor
timestamp: February 25, 2025, 06:11:06 pm
content: Quote from: floobydust on February 16, 2025, 03:57:56 amI made a 2nd Mr.C superprobe, and this new 1 I've put inside Excel breathmint metal cans. They are about 3" tall, but not very big.I don't believe in ghosts, but I'm pretty sure when I turn off all the lights in the middle of the night, and walk around with this thing, I'm finding ghosts !!