this post was submitted on 15 May 2024
10 points (100.0% liked)
Ask Electronics
3148 readers
2 users here now
For questions about component-level electronic circuits, tools and equipment.
Rules
1: Be nice.
2: Be on-topic (eg: Electronic, not electrical).
3: No commercial stuff, buying, selling or valuations.
4: Be safe.
founded 1 year ago
MODERATORS
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
Update: can't load the images some Lemmy errors pop's up ...
Give us a link instead. That said, read on.
In general, antennas are not like a "normal" circuit where things need to connect to each other to work.
Most antennas are made of two halves or poles, hence the name, dipole.
A Yagi antenna is a dipole with separate elements to focus and reflect the radio waves. These elements are normally not connected to each other.
In a typical Yagi only one pair, the dipole, is the driven element. The many (shorter) elements are directors, the one (or two) behind the driven element is the reflector.
A coaxial cable has two conductive elements, the core (the middle bit of metal) and the shield (the outer braid). These should normally not connect to each other.
You connect each coax conductor to its own dipole element. It generally doesn't matter which coax conductor connects to which dipole element.
Source: I'm a licensed radio amateur.
I recently setup a Meshtastic lora node and realized antennas are complicated... I never knew there were ones that are most resonant on specific frequencies and stuff, the importance of having the impedance close to 50ohms for best performance. And fake amazon ones that give you only 8cm of antenna wire inside a 37mm shaft ๐คฆโโ๏ธ
That said, I am shocked that something the size of my thumb can communicate 1km through buildings, and uphill to the other side of my village on such low power. This radio stuff is really fascinating.