Size of this preview: 776 × 599 pixels. Other resolutions: 311 × 240 pixels | 622 × 480 pixels | 995 × 768 pixels | 1,280 × 989 pixels | 1,344 × 1,038 pixels.
Original file (1,344 × 1,038 pixels, file size: 153 KB, MIME type: image/jpeg)
 | This is a file from the Wikimedia Commons. Information from its description page there is shown below. Commons is a freely licensed media file repository. You can help. |
Summary
| Description |
English: A portable military wireless station in 1922, operated by members of the 101st Signal Battalion, 2nd Corps, US National Guard Signal Corps, on field training near Peekskill, New York. Two guardsmen crank a hand-powered electric generator (left) as a third (center) operates an early vacuum tube transmitter sending text messages in Morse code using a telegraph key. The source (p. 58) says the equipment is an SCR-99, which can transmit on wavelengths between 900 m (330 kHz) and 1500 m (200 kHz). It uses VT-1 triodes for receiving and VT-2 triodes for transmitting, and has a range of about 100 miles with 320 V on the transmitting tubes. Caption: TRANSMITTING IN THE FIELD: The power for operating this equipment is furnished by the hand generator. Note the collapsible metal mast that serves as a support for an umbrella antenna |
| Date | |
| Source | Retrieved August 27, 2013 from Alfred M. Caddell, "Radio fans who are paid to learn" in Popular Radio, Popular Radio Inc., New York, Vol. 2, No. 1, September 1022, p. 53 on Google Books |
| Author | Alfred M. Caddell |
Licensing
 |
This media file is in the public domain in the United States. This applies to U.S. works where the copyright has expired, often because its first publication occurred prior to January 1, 1929, and if not then due to lack of notice or renewal. See this page for further explanation.
|
 |
 |
File history
Click on a date/time to view the file as it appeared at that time.
| Date/Time | Thumbnail | Dimensions | User | Comment | |
|---|---|---|---|---|---|
| current | 08:34, 19 January 2014 | | 1,344 × 1,038 (153 KB) | Chetvorno | User created page with UploadWizard |
File usage
The following page uses this file:
Global file usage
The following other wikis use this file:
- Usage on ar.wiki.x.io
- Usage on es.wiki.x.io
