raatools/

📻 SDR / RF Tools

Recherche MAC, fournisseurs Bluetooth, calculatrices de fréquence d'antenne

Radio and hardware-identifier lookups: antenna lengths for a frequency, and the vendor behind a MAC or Bluetooth address.

Small category, specific jobs. The antenna calculator is the one that saves real time — cutting wire to the wrong length is a slow way to discover an arithmetic error.

Which tool do I want?

If you…Use
You are cutting an antenna for a frequencyCalculatrice d'antenne
You have a MAC address and want the manufacturerRecherche de fournisseur MAC
You are identifying a Bluetooth deviceFournisseur Bluetooth

Velocity factor is why your antenna is short

The textbook quarter-wave length assumes a signal travelling at the speed of light in free space. In actual wire it travels slower — typically 95% for bare wire, and as little as 66% in coax — so a physical antenna is cut shorter than the free-space formula suggests. That factor is where most first-attempt antennas go wrong.

Randomised MAC addresses are the other thing to know before trusting a lookup. Phones have advertised random addresses while scanning for years, and a randomised address has the locally-administered bit set in the first octet, so it maps to no vendor at all. A lookup returning nothing usually means the device is protecting its identity, not that the database is incomplete.