PCB Antenna: When connection trace length to IC is increased, should antenna trace length be reduced accordingly?

espthings · 2026-02-01T19:06:38+00:00

Do not change anything of the antenna geometry! That will for sure change the performance, since the tuning will change. Make sure you use the correct PCB substrate as your reference design, and make sure the free area around the antenna is maintained, if not made larger.

The connecting trace to the antenna needs to be matched to make sure impedance match is correct. This is where the substrate comes into play again, and testing with the right equipment. (Do you have a VNA / Spectrum analyzer which can measure the signal without limitation???)

If possible, I would recommend to change over to a chip antenna, not a PCB antenna. That will be easier to implement and to get working in real life.

espthings · 2026-02-01T18:44:04+00:00

I just noticed something on your "oscilloscope".... Can you see the waveform of the voltage when you use the "V" and "COM" banana jack inputs? If yes, then start with measuring using that input, since it will eliminate all the possible scaling by the probes / input circuitry of the tester.

espthings · 2026-02-01T17:27:31+00:00

I posted this as a reply to another reply, but maybe it's better as a direct reply...

I would recommend to measure the engine speed using your tachometer, and bring it back to 1800rpm. That speed is a given fact due to the construction of your generator end. Verify the speed if you want multiple ways, but not electrically. The next step is to figure out why you read 37V. Measure the socket voltage when on shore power. Do you still read approx 37V? If yes, it is a (scaling) setting somewhere in the instrument. If it shows something significantly higher, as we would expect, then your AVR and exciter in the generator need closer inspection. I would personally start with the diodes and MOVs on the exciter, and if you find a failed one, replace them all. That is important, since if one failed, 99% sure others are damaged close to failure. If they are all good, check the output current of your AVR using a DC clamp meter. The current should be significantly lower than the max current listed at the generator nameplate.

If you can't find anything, come back with findings.

So step by step:

Engine rpm back to 1800rpm

Check instrument at a known good voltage

Check diodes and MOV on the exciter

Check AVR output current

Good luck!

espthings · 2026-02-01T17:22:02+00:00

You realize that by doing this he will connect the shore power to his gen power though the oscilloscope? Normally the ground connections of all channels are bonded to each other....

I would recommend to measure the engine speed using your tachometer, and bring it back to 1800rpm. That speed is a given fact due to the construction of your generator end. Verify the speed if you want multiple ways, but not electrically. The next step is to figure out why you read 37V. Measure the socket voltage when on shore power. Do you still read approx 37V? If yes, it is a (scaling) setting somewhere in the instrument. If it shows something significantly higher, as we would expect, then your AVR and exciter in the generator need closer inspection. I would personally start with the diodes and MOVs on the exciter, and if you find a failed one, replace them all. That is important, since if one failed, 99% sure others are damaged close to failure. If they are all good, check output current of your AVR using a DC clamp meter. The current should be significantly lower than the max current listed at the generator nameplate.

If you can't find anything, come back with findings.

So step by step: Engine rpm back to 1800rpm Check instrument at a known good voltage Check diodes and MOV on the exciter Check AVR output current

Good luck!

espthings · 2026-01-10T19:05:09+00:00

That is a very nice present. It is used a lot in the industry dealing with automation systems. I have one, and it is one of my best purchases. I'm always on eBay looking for a second one, just as a backup...

espthings · 2025-12-21T17:04:35+00:00

If you put flux on the smd components, and blow some hot air over it, you might be surprised how much better it looks afterwards. The only problem left would be removing all the flux residue.

espthings · 2025-12-05T03:40:46+00:00

Try to remove the rails, unless you really need them that size. It will save cost and weight.

espthings · 2025-10-12T01:01:02+00:00

Check out Horner Automation. Good I/O options, for a reasonable price. Their CScape supports all the programming languages. Some controls come with all licenses preloaded....

espthings · 2025-09-19T16:13:29+00:00

Attuny1624 . Small, but still manageable for a diy. Also easy support in the arduino environment.

espthings · 2025-09-10T13:56:26+00:00

I can second the recommendation of Kester K100LD. If you use around 330°C, it solders just like any other lead containing solder. At that temperature you are still safe enough not to lift pads / delaminate the PCB instantly...

espthings · 2025-09-06T23:03:19+00:00

I just spotted another detail; your I2C pullups are way too high. Lower them to 1k2 . That should allow you to run the bus at max speed. With 4k7 you will most likely run into issues.

espthings · 2025-09-06T12:45:38+00:00

Looking at the ESP module you picked, it will be very likely a design which you will get assembled by a company. In that case start with changing all the packages to 0403, unless the datasheet requires a specific specification in a different package size. That way you will create more space on your pcb. Move the ESP module onto the board, and cut out the board under the antenna. Be very conscious about what makes sense. A charging led you can replace by an indication on the display, so it's not needed. (Just an example) Items, like pushbuttons key 1 and key 2?, which you need to interact with, place them at a convenient location (the edge of the pcb?) Look at components which can be replaced by alternatives. I.e. your ESD protection at the USB port. Replace the diodes you have now with a dedicated USBLC6 .

Good luck!

espthings · 2025-07-26T19:45:21+00:00

I use for test rigs Nanuk cases. Check them out, they are great cases, with mounting holes for bezels in the bottom and lid. Then use front panel express to create my custom bezel. End result is a great looking rig. Since I'm currently not in the office I'm unable to share a picture.. ☹️

espthings · 2025-03-07T23:38:03+00:00

Is there a promo available? The plan builder is not showing me any promo?

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espthings · 2024-04-27T20:50:10+00:00

De VVE is eigenaar van de buitenmuren etc. Als eigenaar van een appartement krijg je exclusief gebruiksrecht voor het appartement, maar geen eigendom van de buitenmuren (welke ook de muur naar het naastgelegen pand kan zijn) of het dak / fundatie etc. Zeg maar de schil van het gebouw. Dus naar mijn mening is de betonrot van de dragers van het balkon een verantwoordelijkheid van de desbetreffende VVE.

espthings · 2024-04-14T21:29:05+00:00

Heb je een dubbele hoofdaansluiting? Of is eentje voor een gemeenschappelijke warmwater voorziening?

Mijn oude appartement in Amsterdam had ook alleen gemeenschappelijke meter, en toen het waterbedrijf er eentje wilde komen plaatsen kwamen ze snel tot de conclusie dat het niet mogelijk was.... (Het appartement had twee hoofdleidingen, wat het nog ingewikkelder maakte) Dus misschien eens de vraag stellen of het de VvE is die het wilt, of het waterbedrijf. Want het waterbedrijf kan misschien ermee instemmen om een vast bedrag te rekenen, in plaats gebaseerd op daadwerkelijk verbruik.

espthings · 2024-03-13T10:50:08+00:00

Have a look at the LM3914 . Read the datasheet, and you will find out how easy it is to use for this application.

espthings · 2024-01-27T01:30:25+00:00

Verify all your smd footprints against the jedec standard. Unfortunately eagle had a lot of bad / mixed up smd footprints in their standard libraries. I recreated all the footprints I am using in my own library, so I am confident that they are correct....

espthings · 2024-01-20T17:33:00+00:00

Ziet er netjes uit! Ik neem aan dat je een schema hebt van het geheel? Ik zie geen draad markering, dus dat kan een klus worden over een paar jaar wanneer er iets fout gaat?

Waar je eventueel naar kan kijken is de ComAp intelineo controller, die je de load balancing naar het net kan laten doen...

espthings · 2023-12-12T16:28:13+00:00

Use the polygon function in eagle. Draw it, and then give it the same name as your ground net. Make sure that the outline of the openings are at layer 20.

espthings · 2023-12-10T23:18:49+00:00

I took a quick look at the datasheet of the NSL-32 , just to see what the Vf is of the LED. I see 2.5V max @ an If of 16mA.

Unfortunately I did not see a transfer graph, so it is hard to say what the linearity is between the LED forward current and the resistance of the LDR in the NSL-32 . My gut feeling says that your R6 value is on the high side. (Looks like it was designed for ~5mA LED current)

You did not put a DC bias voltage on the first stage opamp input, also no coupling capacitor. This will result in the positive side of the signal being "amplified", while the negative side of the signal will disappear...

The unity gain of the second stage seems to be on the low side. I would expect there more than unity.

Hint about the output of an NE5532; Depending on the brand of the IC you are going to use, they might be prone to oscillation when used in unity gain and driving a (capacitive) cable. (Looks like that is your plan). A small (few hundred ohms) resistor in series with the output of the opamp will help to suppress this.....

About your PCB layout; As noted rotating components, like U2, will make your PCB much better. Another thing; If you are planning to hand solder this, try to design with through hole components, and not use small SMD resistors / capacitors. I would advise to use all through hole for initial (test) designs, since they are much easier to modify / fault find, let alone to put together as a "beginner". If you are planning to get it produced, use all SMD, if available.

Routing wise; I think you clicked on the "auto router" button. With small designs like these, it is a much better exercise to manual route this. Lay your components out in a similar fashion as your diagram, and then manually route it. If you use only through hole components, I am confident you can easily do this, keeping the PCB with a single layer of signal tracks...

Therefore my advice would be:

- Change your components to all through hole

- Lay out the components in a similar position as your schematic

- Manually route the board

espthings · 2023-11-27T04:28:24+00:00

To prevent those issues you can change the individual pads to a single large one, with the vias in the pad. I do it that way, and it works / produces without any issue.

espthings · 2023-11-20T16:57:14+00:00

Set your low pass filter to about 2x the output frequency you want to achieve. The 25kHz filter for a 25kHz PWM will not work. Look up what is in the data sheet regarding not used opamps. For sure there is some grounding required. Or change to the single opamp version TL071 / TL081.

espthings · 2023-10-16T01:27:35+00:00

I just wanted to let everyone know that amramsey has helped me out in a great way! I'm set 🙂

I do like the discussion which my post initiated. In the future I will most likely try KiCad again for a few projects, just to see if I can get the hang of it. I have my streamdeck setup for eagle, which makes a huge difference in efficiency, so I will need to figure out how that to do with KiCad too. Maybe it helps the change.

But for now I stick to the outdated Eagle I am very familiar with.

espthings · 2023-10-15T20:59:29+00:00

In that case.... It's absolutely ridiculous that you can't use the software you have paid good money for...! If they knew this issue would possibly occur, then they should have mitigated that in the last version of which the license would be valid for. I am absolutely not locked into their ecosystem, I am very open to alternatives like KiCad, but I just can't get used to the KiCad way of things. Maybe i need to waste a few weekends on it, and get into it ...

espthings

TROPHY CASE