📻 SDR / RF Tools
MAC lookup, Bluetooth vendors, antenna frequency calculators
Identify vendor from MAC address OUI prefix
Open tool →Look up Bluetooth Company ID (e.g. 0x004C = Apple)
Open tool →Frequency ↔ wavelength for antenna design
Open tool →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 frequency | Antenna Calculator |
| You have a MAC address and want the manufacturer | MAC Vendor Lookup |
| You are identifying a Bluetooth device | Bluetooth Vendor |
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.