Radio Hams test APRS underground

Bob Bruninga, WB4APR, has been testing how the amateur radio Automatic Packet Reporting System (APRS) can be used to extend radio communications underground

Bob led a group of radio amateurs earlier this month to Mammoth Cave - the world’s longest known cave system - at Mammoth Cave National Park in Kentucky to test how the Automatic Packet Reporting System (APRS) can be used as a means to extend radio communications underground.

““When used underground, VHF and UHF radios can only work within a few hundred feet of each other and only when in the line of sight of another radio,” “This makes routine use of these radios of little value when underground; however, when APRS radios act as packet digipeaters, these few hundreds of feet can be extended by an order of magnitude.””

— Bob Bruninga, WB4APR

Bruninga, a senior research engineer at the US Naval Academy, developed APRS as a global, on-air protocol for supporting handheld position reporting and text messaging via VHF radio.

Read the full ARRL story - http://www.arrl.org/news/bob-bruninga-wb4apr-takes-aprs-underground

Digital TV test transmissions from Mt Belmont

Transmission of the unmodulated CW carrier continues on 506 MHz, with horizontal polarisation. The maximum EIRP is +20 dBW (100 Watts) towards the North East.

Calibrated coverage measurements, at more than twelve locations, confirm that the transmit antenna is performing as expected. Reception reports are welcome.

The transmission is receivable over a 180° arc, from the North West, through North East, to South East. There are two minimas: one in the direction of Titahi Bay and the other in the direction of Seaview. Transmissions over the other 180° arc, from South East, through South West, to North West are about 20 to 26 dB weaker.

The “breadboard” version of the digital modulator was completed on Wednesday 27 th February 2013 and is now undergoing intensive quality testing.

Components have been ordered for constructing the permanent power amplifier.

For more information, and frequent updates - http://www.vhf.org.nz

NZART Website -  http://www.nzart.org.nz

STRaND-1 amateur radio smartphone CubeSat to launch 25 February

The world’s first 'smartphone-sat' STRaND-1 is ready to launch at the end of February
The satellite was built in Guildford by volunteers from the Surrey Space Centre (SSC) and Surrey Satellite Technology Limited (SSTL) in their spare time. It is planned to be launched on February 25 into a 785 km orbit by the Indian Space Research Organisation (ISRO) on the PSLV-CA (PSLV-C20) rocket.

The innovative STRaND-1 CubeSat will carry a Google Nexus One Android smartphone into space to demonstrate the feasibility of using cheap smartphone electronics to control a spacecraft.

Smartphones contain highly advanced technologies and incorporate several key features that are integral to a satellite – such as cameras, radio links, accelerometers and high performance computer processors – almost everything a spacecraft needs except the solar panels and propulsion.

A software-based speech synthesiser will be included to pay homage to the UOSAT family of amateur radio satellites (OSCAR 9 and 11) that were launched in the 1980's. There will be an amateur radio AX.25 packet radio downlink on 437.575 MHz using data rates of 9k6 or 19k2 bps.

See the STRaND-1 videos and further information - http://www.uk.amsat.org/?p=12196

Read the BBC News story - http://www.bbc.co.uk/news/science-environment-21361204

Dr Chris Bridges talked about STRaND-1 on the BBC Radio 4 show Material World broadcast on Thursday 7 February . A recording can be heard until 14 February 2013 - http://www.bbc.co.uk/programmes/b01qfj3l The STRaND-1 segment starts 08:55 into the recording.

The world’s first smartphone in Space ‘STRaND-1’ ready for launch - http://www.sstl.co.uk/News-and-Events?story=2117

STRaND-1 on Facebook - https://www.facebook.com/nanosats

AMSAT-UK - http://www.amsat-uk.org/