Doppelmembran-Würgenippel

#nerd #DIY #maker #electronics #electric #3Dprint #fiberoptic #cabletv #technician #rf

Frustrated by mankind and overcaffeinated

No hope ultras

Last Notes

2026-07-02 13:36:17 UTC

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Direct messaging in meshcore is a mess.
In big meshes the real text messages drowning between all the DM broadcast path/request messages.
I switched off path updates (auto route finding) because it do more harm than good, often routes go to long unstable routes, while the short reliabld one is ignored.
At least with latest mc firmwares region settings can be enforced to all the DM message broadcast too.
Its such low overall bandwith, it nearly chokes itself

2026-07-01 20:33:09 UTC

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Great idea to tunnel abrouting protocol over a network without routing, flooding the mesh with traffic and get real meshcore messaging more unreliable
This is why now and then blacklisting feature is wanted

2026-02-08 15:50:14 UTC

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Can you get a repeater node in the air with 15cm solar cell and a little battery through the cold and dark winter days on a hill, 2 weeks without sunshine?

2025-08-08 17:26:53 UTC

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Faster melting rates with 1.75 and less power needed at the feeder.
But going away from 2.85 filament is a 2018 thing, when did you order last time 😁
The 3 mm stuff come from plastic welding rods used in first experiments to build reprap printers years ago

2025-07-22 14:06:12 UTC

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You breathe the smoke in, while the material degrades.
I would get decicated printer for abrasive materials only and do equip only this one with the hardened nozzle.
Doing the normal stuff with normal brass nozzle on another printer.
Or modify the printer to swappable hotends
+1 for nozzle defect influenced underextrusion.

2025-04-19 23:20:30 UTC

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The E axis Stepper? If this would be hotter than 60°C you could not print PLA because the extruder gear would melt the plastic in the feeder.
Print with ABS/ASA will be fine

2025-03-11 22:44:54 UTC

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1276 vs 1278 different chips for 433 vs 866-915
Sx1262: same chip, but different rf filter circuit, because with 400-1000 open filter you cant get rid of 433 first harmonics.
You need to buy 433 OR 886-915. Its not the same thing.

2025-03-04 11:35:12 UTC

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I dont plan to buy one.
Maybe the filter have inbetween screws to reduce coupling for deeper filter reponse.
There is a sweet spot between more insertion loss and less deep rejection of unwanted frequency.
On mine i probed this with open enclosure, was not very complicated. Then measured and integrated a little wall on the bottom part in the right height.
I want to get my experiments more sophisticated now and build one with 3 resonators and then four.

2025-03-03 22:55:38 UTC

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I have seen this one before, still sold out.
There is a Datasheet linked in the shop.
Nice trace.
The screws are very close to each others.
Maybe not every screw with nut have a resonator element.
Would like to see the inside 🧐

2025-03-03 22:33:39 UTC

I have build another one of the experimental #lora #meshtastic cavity filter for 868mhz
This time i tried to add two notchfilters out of coaxial cable stubs.
In the picture you can see little improved frequency response at the cost of additional 1dB insertion loss.
Set the notch filters closer to the center frequency add more insertion loss, so i dont want to do this.
50dB attenuation for broadcast,
32dB @800MHz
20dB @910Mhz
For LTE/GSM cellular service frequency it could have deeper response.
At places with powerful Broadcast transmitters 50dB attenuation may need to get better too.
So i decided to do the next step and build a new one with 3 resonator elements.
Ill report my results here.
https://files.techhub.social/media_attachments/files/114/100/828/555/535/190/original/7fd0531b9481a437.jpg

2025-01-09 00:02:07 UTC

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To me it looks like none of the boards have proper battery low voltage menagement.
The software integrated should at least have calibrated adc scale factor to get good measurements (wait after every change 1-2 minutes because the displayed values are results of some measurements summared)
I see two options: build a proper one yourself as separate hardware (need hysteresis and very low power consumption)
Or
Get it overpowered to never drain the battery by bigger battery capacity and solar panel size.

2024-01-18 09:31:08 UTC

Trying to make cabletv infrastructure beautiful, when installing the distribution boxes
https://files.techhub.social/media_attachments/files/111/776/237/758/994/357/original/6184f1ebce2d4c05.jpg