0xdecafbad.com

All things radio related, with emphasis on ham radio.
Learn Morse Code by telephone FREE! call +1 218-339-8073
if you have unlimited minutes to US numbers, whether by mobile phone, voip line, or landline you can call for free and learn morse code.

I think I did not make some aspects of skywave clear enough so this article should clarify some things.  It is going to get a little more technical than I had hoped, but I fear that is unavoidable in order to make some things clearer.  I do not think this article is overly complex and should be understandable by most everyone.

There is a layer of the atmosphere that contains charged particles.  This layer is called the ionosphere.  The sun charges the particles in the ionosphere, when it is daylight they become charged, when the sun sets they start to lose their charge and continue to lose their charge until sunrise the next day. (continue reading…)

You have a radio transmitter and want to find someone to talk to.  There are two ways that you can accomplish this.  You can just tune around and listen for someone else to talk or you can just start talking hoping that someone hears and responds to you.  If everyone is just listening for someone else the band may seem dead even though many are monitoring so learning how to call is important.

There are a few different ways you can accomplish this, one would just be pressing the PTT button and asking “is there anyone out there?”, additional Pink Floyd lyrics optional.  This may work for unlicensed bands, but licensed bands generally have a bit more protocol to them.  I will discuss the way that works well for ham bands in the HF region.  This can be used on non-ham bands as well, although a slightly modified version may be more suitable there. (continue reading…)

If you did not start at the beginning you should read part 1 first.

Propagation

There are two different ways that radio signals go from the transmitter to the receiver. Skywave and groundwave. The names are like they sound, the radio wave travels either across the ground or the sky. Groundwave communications are shorter range, and usually direct from one radio to another. Skywave will go up to the ionosphere and bounce back down to the Earth. Skywave generally does not have the issues with polarization that were mentioned above. (continue reading…)

If you did not start at the beginning you should read part 1 first.

Antennas

Antennas are a critical component in a radio device. They will gather the very weak electromagnetic wave that is in the air and convert that into sound for you to hear. They will also emanate the radio signal so that other radios can receive it. Not all antennas are the same, there are several properties that make an antenna suitable for a particular radio. (continue reading…)

If you did not start at the beginning you should read part 1 first.

Popular Bands

In order to make things easier for everyone groups of frequencies that have a common use are grouped into bands. If you are looking for a specific type of radio signal basic knowledge of the bands is essential. Before I talk about the bands I want to talk about the two different types of transmitting. There is broadcasting, or a one-way transmission usually for the purposes of educating or entertaining and there is communicating. Communication requires a two-way flow of information, which implicitly requires both parties to have both a transmitter and a receiver (often built into the same radio device). Some bands are only broadcasting while others are only for communicating. (continue reading…)

If you did not start at the beginning you should read part 1 first.

Spectrum

Radio frequencies span a wide range of frequencies. Radio is below light, X-rays, gamma rays and other emanations. Radio comprises the frequencies 3Hz to 300GHz. A Hz or Hertz is a measure of how many cycles per second an oscillation occurs. 1GHz oscillates 1 billion times per second while 10Hz oscillates 10 times per second. For reference visible light is 300THz or 300 trillion times per second. (continue reading…)

Crash course in radio or how to communicate when the zombies attack

This is a multipart series attempting to give some basic information on radio communications.

Scope

This guide will not be overly complex. It will leave out many details and over simplify some other details for the purposes of making the information available to a wider range of people. A lot of the “why” is left out focusing instead on the “how”. There are a lot of books that cover the “why”, if you are interested in that you should locate some texts (some are free on the internet) and study those.

Who is this guide for:

• You want to learn the basics of radio operation but do not want to learn all the particulars that could be handy for designing your own system.
• You are just starting out and want to get the basics down
• You think it may be good to know about radios in case communications are knocked out
• You are looking to purchase an emergency radio (continue reading…)

Despite the efforts of some people typing angrily into their keyboards, possibly from their mothers basement, questioning my intelligence for trying to unlock some secrets about the FT-897 radio I am pushing on. I went through some notes I made and comments I received from others in September 2009 and came across some information that I had totally forgotten about. My life distracted me from this project, and now I have some time I hope to make more headway. (continue reading…)

I want to write a web app for the radio.  My initial target is an Asus WL-520GU wifi access point.  It has a USB adapter, and I can run linux on it.  While it is s
mall and embedded I can get enough on the $30 access point to control my radio.  I question if it has enough cpu to successfully stream the audio in anything other than PCM, but even a PCM link would not be terrible.  It would mean that my radio can stay stashed in the basement while I am upstairs in the office, and that is all I really want. (continue reading…)

The CAT protocol is written for the lowest common denominator, and it was written a long time ago.  As a result it does not support every command that a radio may have.  I am not sure why Yaesu did not extend CAT for radios and if your radio does not support that command an error is returned.  I can understand from a development cost and support cost perspective not wanting to have a new variant of CAT created for each radio they make.  They can also run out of commands fairly quickly or have issues with similar but not identical radios.  Regardless of why, the fact remains that CAT does not let you do everything the radio can do. (continue reading…)