DIY Variable Capacitor using Aluminium Foil

[@eugenepohjola258]

Howdy. Nice idea. Very suitable for further development like scaling up and using several pipes. Regards.

[@joewoodchuck3824]

Nice design, not that it can't be done without a 3d printer. Foil might be ok for signal level circuits, but not for power handling. 7 mhz for example needs 1 mm/.040" thickness plates using the 5 skin depth rule of thumb. Forget about using it for a magnetic loop antenna.

[@oobihdahboobeeboppah]

The meter is marked on the screen as nano. This type of capacitor would be adequate for receiving purposes only, transmit power of any appreciable amount would require something other than aluminum foil and a better dielectric. I would recommend instead of using paper and aluminum foil simply replace the two plates with pieces of copper or aluminum pipe. Instead of using a manually turning knob which looks to be very inconvenient, a stepper motor could be used.

[@RobertLeeAtYT]

No, I'm not so sure. This deserves more investigation. The dielectric constant of PLA, the standard 3D printing plastic is a bit higher than 3, versus 1.0 for air and 3 to 6 for glass. The dielectric strength of PLA is 33 kV/mm, versus 3 kV/mm for air. So that looks promising for use in a transmitting magnetic loop for more than QRP levels. What I don't know is the dielectric loss for PLA. Wouldn't do to have the thing melt

[@joewoodchuck3824]

What about skin effect depth? Foil can be quite lossy depending on frequency. A motor of any sort can introduce it's own set of problems near an antenna.

[@wesleysandifer6157]

Yep. I'll just run right down to the store and buy me a 3-d printer and learn how to right g-code. Oh wait. I'll just buy a over priced tuning cap. Great job by the way. I just don't have that luxury.

[@pulpo439]

Guantes con ratos, no cazan gatos 😆 😂 🤣 🤭 👀

[@GypsyTalesAxom]

nice

[@makertronics3330]

Thanks

[@pulpo439]

Algo (bastante) chapucero.

[@carlomaglietti2081]

nessuno si e accorto che il condensatore e' in corto circuito . con lo strummnto misurava gli ohm non la capacita .....svegliaaaa

[@РоманОрищенко-г6н]

Что это

[@oobihdahboobeeboppah]

The meter is marked on the screen as nano. This type of capacitor would be adequate for receiving purposes only, transmit power of any appreciable amount would require something other than aluminum foil and a better dielectric. I would recommend instead of using paper and aluminum foil simply replace the two plates with pieces of copper or aluminum pipe. Instead of using a manually turning knob which looks to be very inconvenient, a stepper motor could be used.

[@bassmanjr100]

Aluminum 4 mil foil tape is very good for RF. Even for 100W rigs. Paper no. Use PVC.

[@oobihdahboobeeboppah]

The meter is marked on the screen as nano. This type of capacitor would be adequate for receiving purposes only, transmit power of any appreciable amount would require something other than aluminum foil and a better dielectric. I would recommend instead of using paper and aluminum foil simply replace the two plates with pieces of copper or aluminum pipe. Instead of using a manually turning knob which looks to be very inconvenient, a stepper motor could be used.

[@poprockshredman494]

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