# Lee De Forest's Early Radio Telegraphy System

> A 1908 patent by radio pioneer Lee De Forest describing methods for transmitting and receiving wireless telegraphy signals using early vacuum tube technology.

- **Patent:** US 879532
- **Original title:** Space telegraphy.
- **Owner:** FOREST RADIO TELEPHONE CO DE
- **Granted:** 1908
- **Status:** Public domain (expired)
- **Times cited:** 2
- **Field:** telecommunications, semiconductors

## What it does

This patent details a system for space telegraphy, which was the early term for wireless radio communication. It focuses on the hardware arrangement for generating and detecting electromagnetic waves across distances. By utilizing early components that would eventually evolve into the triode vacuum tube, the system allowed for the modulation of electrical signals to transmit information wirelessly through the air.

## What it does NOT cover

- Does not cover modern digital signal processing or binary data transmission.
- Does not cover the later invention of the Audion triode amplifier itself, which was patented separately.
- Does not cover satellite-based communication systems or modern cellular networks.

## The clever bit

The patent explores the use of early electronic oscillation to create a more stable, continuous signal, which was a significant improvement over the noisy, broad-spectrum interference caused by primitive spark-gap transmitters.

## Real-world examples

1. Early wireless telegraphy stations
2. Pioneering radio broadcasting equipment

## Why it matters

Lee De Forest was a central figure in the birth of radio. This patent represents the foundational era of wireless communication, moving the industry away from spark-gap transmitters toward more controlled, continuous-wave transmission methods.

## Frequently asked questions

### What does Lee De Forest's Early Radio Telegraphy System cover?

A 1908 patent by radio pioneer Lee De Forest describing methods for transmitting and receiving wireless telegraphy signals using early vacuum tube technology.

### Who owns patent US 879532?

FOREST RADIO TELEPHONE CO DE owns this patent, granted in 1908.

### When does this patent expire?

This patent has expired and is now in the public domain — anyone can use the invention freely.

### What is patent US 879532 cited by?

This patent has been cited by 2 later patents that build on its ideas.

### What problem does this patent solve?

Lee De Forest was a central figure in the birth of radio. This patent represents the foundational era of wireless communication, moving the industry away from spark-gap transmitters toward more controlled, continuous-wave transmission methods.

### What does this patent NOT cover?

Does not cover modern digital signal processing or binary data transmission.

**Full plain-English explainer:** https://patentbrief.org/patent/us/879532/de-forest-audion-vacuum-tube

**Original patent:** https://patents.google.com/patent/US879532

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_Source: PatentBrief — https://patentbrief.org. Patent facts are from public records; the plain-English explanation is PatentBrief's._


## Related patents

Semantically similar inventions in the PatentBrief corpus:

- [How Marconi Patented Early Wireless Telegraphy Signals](https://patentbrief.org/patent/us/586193/radio-wireless-marconi) — Guglielmo Marconi's 1897 patent for sending electrical signals through the air to enable early wireless communication.
- [The Invention of the Transistor](https://patentbrief.org/patent/us/2524035/point-contact-transistor) — Bell Labs' 1950 patent for the point-contact transistor, the fundamental electronic component that makes all modern computing possible.
- [How Samuel Morse Patented the Electric Telegraph System](https://patentbrief.org/patent/us/1647/morse-telegraph) — Samuel Morse's 1840 patent for the electric telegraph, which enabled long-distance communication by sending electrical pulses over wires to represent letters.
- [Alexander Graham Bell's Patent for the Telephone](https://patentbrief.org/patent/us/174465/bell-telephone) — Alexander Graham Bell's 1876 patent describing the method and apparatus for transmitting vocal sounds telegraphically, effectively inventing the telephone.
- [How Edwin Armstrong Invented the Superheterodyne Radio Receiver](https://patentbrief.org/patent/us/1342885/superheterodyne-radio-armstrong) — A foundational 1920 patent by Edwin Armstrong that describes the superheterodyne circuit, the technology that allowed radios to tune into specific stations clearly and reliably.