Math Behind SSB Explained

Al Williams,  WD5GNR has published an article describing how voice is transmitted over radio waves

AM, or amplitude modulation, was the earliest way of sending voice over radio waves. That makes sense because it is easy to modulate a signal and easy to demodulate it, as well. A carbon microphone is sufficient to crudely modulate an AM signal and diode — even a piece of natural crystal — will suffice to demodulate it.

Outside of broadcast radio, most AM users migrated to single sideband or SSB. On an AM receiver that sounds like Donald Duck, but with a little work, it will sound almost as good as AM, and in many cases better.

Media Article - https://hackaday.com/2018/01/01/why-is-donald-duck-on-the-radio-math-behind-single-sideband-explained/

Battery Powered 'Smart Bags' Raise Safety Concern

Following on from the hazards caused by hover-boards, dodgy chargers and exploding mobile phones, all associated with lithium batteries and fires, a new type of travellers’ luggage known as ‘smart bags’ are starting to get attention for their built-in lithium batteries. These small but high capacity batteries are a power source for charging external devices or to provide power to the wheels of the bag.

Passengers trying to check them in as carry-on bags are warned by two Asian airlines that if they are fitted with non-removable lithium batteries, they will be banned from flights.

3D Printed Radio

Digital Trends are promoting Texas Based Electronic Enthusiast Sage Hanse, and how he creates projects using 3D Printing

Called a crystal radio receiver, or sometimes a “cat’s whisker receiver,” this is an incredibly simple type of radio receiver that was popular in the earliest days of radio. The only power it requires to work is the received radio signal, which is used to produce sound. It is named after its most important component, the crystal detector or diode.

“AM radio was one of the first ways of transmitting audio to a very broad audience in the early 1900s, but it is still very popular today. It starts with the radio station converting their audio sound waves into electromagnetic waves, which can travel great distances.”

— Sage Hansen

Each radio station uses a specific frequency that is constant, but the sound waves are mixed so they amplify and modulate the base radio wave. What makes the crystal radio so exciting is how simple the circuit is, and how it can be made out of normal household items.