GoTenna turns your smartphone into a CB radio

 

The $300 GoTenna turns your smartphone into a CB radio, lets you send messages when you have no cell signal!


If you’ve ever had a cell phone, you know how frustrating it can be when your network fails. Areas with little to no signal can be absolutely infuriating, and overcrowded events can be just as bad. To sidestep this problem, the folks at GoTenna have developed their own ad-hoc network for sending messages. It’s an incredible concept, but with an asking price higher than most smartphones, there’s no way that this implementation is going to take off anytime soon.

The GoTenna is essentially a small, low-power (2 watts) radio transceiver. It’s powered by a lithium-ion battery, and it connects to your smartphone or tablet via Bluetooth. The company behind GoTenna is rather vague about the technical specifications of the device, but given the max claimed range (up to 50 miles), it probably transmits on a very low frequency (and probably has very low max bandwidth). GoTenna creates an ad-hoc, encrypted network between any other GoTennas in range. It’s kind of like a smartphone equivalent of a CB radio.

You can connect the GoTenna to any iOS or Android device via Bluetooth. After that, all you have to do is download the GoTenna app and fire off a message to anyone else who might be in range. Depending on your elevation and environment, the signal can travel upwards of 50 miles. By default, only your intended recipient will be able to read your message, but a “shout” feature allows messaging any GoTenna user within range. It doesn’t use cell towers or WiFi at all, so it’ll work even if all other forms of communication are unavailable.

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Watch George, K3GP discuss the history of RTTY

 

DIGITAL COMMUNICATIONS IN AMATEUR RADIO: CONVERSATIONAL DIGITAL MODES (PSK, RTTY, MFSK, OLIVIA)


Radioteletype

Radioteletype (RTTY) is a telecommunications system consisting originally of two or more electromechanical teleprinters in different locations connected by radio rather than a wired link.

he first form of data transmission or digimode to gain widespread acceptance was known as radio teletype or RTTY. RTTY was widely used for commercial applications where it enabled printed messages to be sent quickly and without the need for a trained Morse operator.

Once surplus equipment started to become available, radio amateurs started to use RTTY, and it soon became popular. In the early days of the use of RTTY, large mechanical teleprinters were used to print the data, but now with the ease of use of computers, these are used to decode and decipher the RTTY transmissions because they are quieter, smaller, more convenient and more efficient.

However with the arrival of computers and their greater level of flexibility and sophistication, other more efficient types of digimode are available but despite this, the amateur RTTY is still widely used.

RTTY Basics

RTTY uses a form of transmission known as frequency shift keying. The code representing the letters consists of a series of bits represented by high and low voltages. In turn these are represented on the radio signal by a shift between two frequencies, one frequency signifying a mark or high voltage and another frequency representing a space of a low voltage.

On the HF bands the carrier for the RTTY signal is shifted between two frequencies, and this gives rise to differing audio tones when a beat frequency oscillator or BFO is used. At VHF and above a frequency modulated signal is generally used for RTTY and this is modulated by an audio tone that changes.

The code for the data to be sent consists of five bits of either a mark or a space for each character. The actual code that is used is called the Murray code or Baudot code. This code is internationally recognised and to accommodate the various international requirements a number of national variations exist, although they are relatively minor.

Letter shift and figure shift codes are sent to change from upper case to lower case and vice versa. Once the code has been sent then the system will remain in that case until the next case-change code is sent. One of the drawbacks of RTTY is the limited set of characters that can be sent – only text and numbers, and very few other characters.

When using RTTY, the data is sent relatively slowly because the mechanical teleprinters could not cope with data any faster and the standard has remained in place to retain compatibility with existing equipment despite improvements in current technology. 45.5 baud is the standard speed for amateur radio HF operation, although other standards at 50, 56.88, 74.2, and 75 baud exist. The RTTY frequency shift between the two tones used to be standardised on 170Hz but this is often increased to 200Hz as a result of the many of the new digital modes. As the difference between the two standards is relatively small there is no incompatibility between them. Typically the 170 Hz difference is generated using audio frequencies of 1445 Hz to represent a mark condition and 1275 Hz to give a space.

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Getting Back In The Game

 

Hi I am CJ Henderson CEO Of The American Basketball Association Australia & I have been around radio since the mid 70’s starting out on CB as a teenager and made some really great connections. We had a Browning Golden Eagle in the house and back then I just knew it was expensive as I got older I realized we were broadcasting with a legend.  I used CB – upper and lower side-band – HAM and then joined the military as Gunners Mate on board the iconic battleship USS Missouri BB63 (Now In Hawaii) and traveled the world and stepped away from radio.

Now living in Australia 30 years I’ve been bitten by the bug again. I thought Radio was dead as everyone I speak to has not used a CB out here and then those that do just use when hiking or 4 wheeling some businesses to keep in touch with staff out on jobs. So I decided to start looking at how I can connect with other people that Like Listening To Long Distance conversations – and I started looking at the cool ways using technology to connect with radio as well so I created Long Range Listeners!

I am trying to get my Aussie HAM license and I am fascinated in all the ways you can pick up radio via the internet – DMR & SDR & Handhelds now days are totally on a new level.

Looking Back – If you think CB’s are only for truckers then you need to meet some of the people here. We used to have Club BBQ’s and everyone got to check out what radio & equipment friends are running in their cars or trucks or Custom Van’s . The Good Old Days!

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Have A Great Day Stop By Our Website For Some Cool Stuff! www.longrangelisteners.club