UK 434 MHz balloons head for Poland

Two balloons were launched from Cambridge on Saturday 13 April 2013, one transmitting video images from a Raspberry Pi. On Saturday evening the M0UPU-11 APRS signal indicated they were over Germany.

The first balloon is flying a Raspberry Pi which transmitted live Slow Scan Digital Video (SSDV) images back to the ground by a pair of transmitters to double the bandwidth. The data was RTTY 300 baud 8N2.

The frequencies used were 434.070 and 434.074 MHz. The balloon call sign was $$PIE.

The second balloon flew a 70cms tracker on 434.450 MHz 50 baud 7N2. Additionally once it entered air space where the airborne use of APRS is permitted a second APRS transmitter was enabled, presumably on the APRS frequency of 144.800 MHz, with the callsign M0UPU-11.

Live video of the launch was streamed by the British Amateur TV Club (BATC) - http://www.batc.tv/

Tracks of both balloons - http://www.spacenear.us/tracker

Direct link to M0UPU-11 APRS track - http://aprs.fi/#!call=a%2FM0UPU-11&timerange=86400&tail=86400

Images from the PIE5 Raspberry Pi balloon transmitted using SSDV - http://ssdv.habhub.org/

Beginners Guide to Tracking using dl-fldigi - http://ukhas.org.uk/guides:tracking_guide

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