Page 27 - EngineerIt March 2021

Iposter is a dynamic network that brings audio, visuals and video together on one poster
page with all elements hot linked. When clicked on any section of the poster, it opens
to a larger image. During a virtual conference, the author can show his paper, play an
difference in the spacing of the tones audio segment or video as he presents. During and after the conference, participants can
and on which tones syncing takes place; access any section of the paper.
those familiar with the modern, weak The South African paper can be viewed at http://hamsci2021-uscranton.
signal digital modes know that they can ipostersessions.com/Default.aspx?s=74-34-37-9E-AA-7E-F5-CF-CF-FD-00-3F-96-71-A9-0E
very easily and reliably be received and
decoded by software and reported on. HamSCI
PI4 is free, allowing any amateur who HamSCI, the Ham Radio Science Citizen Investigation, is a platform for the publicity
is set up for digital modes to be able to and promotion of projects that are consistent with the following objectives:
easily receive, decode and report on the - advance scientific research and understanding through amateur radio activities.
next generation beacons received. It is - encourage the development of new technologies to support this research.
available as a standalone package called - provide educational opportunities for the amateur community and the public.
PI-RX and has been incorporated in the
MSHV software package also used by a HamSCI serves as a means for fostering collaboration between professional researchers
number of VHF and above enthusiasts. and radio amateurs. It assists in developing and maintaining standards and agreements
The MGM signal generated by
between all people and organisations involved. Web URL: www.hamsci.org
the next generation beacon does not
only generate a PI4 sequence. It also
generates the beacon ID CW and sends
out a frequency accurate tone that can be Project progress
used for frequency checking. The beacon The first next generation beacon is currently being tested in Pretoria. It is fully operational
therefore caters for automated reception at grid square KG44CH on a frequency of 144.425 MHz. The output power is 25 W into
of the PI4 digital sequence, aural 2x14 element stacked Yagi antennas with approximately 15 dB gain point in a direction of
reception of the CW ID and a frequency 222 degrees.
accurate signal that can be used to check Once fully tested, the beacon hardware will replace the current modified CW beacon
the accuracy of the receiver. in Bethlehem.
The license requirements are to have Monitoring and reporting of the beacon can now be automated using either PI-RX or
frequency measurement equipment, but the MSHV software package, and automated reporting will be able to be done to any of the
the quality and accuracy of this equipment reverse beacon networks that are currently operational.
is not specified. Most affordable frequency
checking equipment is fine for HF Student research
frequencies, however as one moves up Weather and tropospheric propagation are closely related and the collected data will offer
to the higher VHF, UHF and microwave many research opportunities for high school learners and students who are looking for
bands, frequency accuracy and stability interesting science projects. n
becomes critical and can be the
difference between making a contact or * WSJT Home Page (princeton.edu)
not. Most operators have no idea how far ** https://www.rudius.net/oz2m/ngnb/index.htm
off frequency their radios actually are, and
having a method to check their equipment
against a frequency accurate signal is an
added bonus.
Next generation beacon
hardware
The NGNB platform consists of the
following functional blocks:
• VCO-PLL which provides a stable
GPS disciplined frequency reference
to the DDS.
• The DDS (direct digital synthesizer)
generates the modulated signal at the
desired frequency.
• GPS is used to provide a reference
frequency to the VCO-PLL as well
as timing for the DDS to ensure
accurate timing of the message being
generated by the DDS.
• RF amplifier to amplify the DDS
output along with the necessary
RF filtering as required in any RF
power chain. The next generation beacon assembled in its final housing

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