The focal distance of the SLR lens. Intuitive chart

Фокусные расстояния в объективе зеркалки. Наглядная графика

The Hobbyist's Guide to the RTL-SDR: Really Cheap Software Defined Radio. Mr. Carl Laufer

A comprehensive guide to the RTL2832U RTL-SDR software defined radio by the authors of the RTL-SDR Blog. The RTL-SDR is a super cheap software defined radio based on DVB-T TV dongles that can be found for under $20. This book is about tips and tutorials that show you how to get the most out of your RTL-SDR dongle. Most projects described in this book are also compatible with other wideband SDRs such as the HackRF, Airspy and SDRPlay RSP. What's in the book?

• Learn how to set up your RTL-SDR with various free software defined radio programs such as SDR#, HDSDR, SDR-Radio and more.
• Learn all the little tricks and oddities that the dongle has.
• A whole chapter dedicated to improving the RTL-SDR's performance.
• Dozens of tutorials for fun RTL-SDR based projects such as ADS-B aircraft radar, AIS boat radar, ACARS decoding, receiving NOAA and Meteor-M2 weather satellite images, listening to and following trunked radios, decoding digital voice P25/DMR signals, decoding weather balloon telemetry, receiving DAB radio, analysing GSM and listening to TETRA signals, decoding pagers, receiving various HF signals such as ham radio modes, weatherfax and DRM radio, decoding digital D-STAR voice, an introduction to GNU Radio, decoding RDS, decoding APRS, measuring filters and SWR with low cost equipment, receiving Inmarsat, AERO and Iridium L-Band satellite data, and many many more projects!
• Guide to antennas, cables and adapters.

How to Become a Spy: The World War II SOE Training Manual

During World War II, training in the black arts of covert operation was vital preparation for the ?ungentlemanly warfare" waged by the Special Operations Executive (SOE) against Hitler's Germany and Tojo's Japan. In the early years of the war, the SOE set up top secret training schools to instruct prospective agents in the art of being a spy. Soon there was an international network of schools in operation in secluded locations ranging from the Scottish Highlands to Singapore and Canada. Reproduced here is one of the most comprehensive training syllabi used at SOE's Special Training Schools (STSs) instructing agents on how to wreak maximum havoc in occupied Europe and beyond. A staggering array of unconventional skills are covered-from burglary, close combat, and silent killing, to utilizing propaganda, surveillance, and disguise-giving an unprecedented insight into the workings of one of WWII's most intriguing organizations. These files, released from the British National Archive, put covert history in readers' hands. Uncover an exciting, little-known part of WWII history and delve into the inner workings of a real spy network. Skyhorse Publishing, as well as our Arcade imprint, are proud to publish a broad range of books for readers interested in history--books about World War II, the Third Reich, Hitler and his henchmen, the JFK assassination, conspiracies, the American Civil War, the American Revolution, gladiators, Vikings, ancient Rome, medieval times, the old West, and much more. While not every title we publish becomes a New York Times bestseller or a national bestseller, we are committed to books on subjects that are sometimes overlooked and to authors whose work might not otherwise find a home.