Join the conversation  on VHF, UHF weak signal communication


Weak Signal communication


AMSATSA  VHF/UHF workshop in conjunction with SARL

 VHF/UHF Workshop

Presented by the SARL and AMSATSA

9 February 2019


Book here

09:00 Registration

09:30 Welcoming
Nico van Rensburg ZS6QL SARL President

09:30 Update on WRC19 Agenda items that impact on VHF and UHF Amateur Radio spectrum

Hans van de Groenendaal ZS6AKV

There are a number of agenda item at WRC19 which take place towards the end of 2019 that could have an impact on Amateur Radio if they are agreed to as they currently stand. The Government Industry Preparatory Group met during January to consider South Africa’s position.

09:45 The cost of a decibel on two metres

Dick Coates ZS6BUN

10:15 VHF and UHF propagation forecasting

Hans van de Groenendaal ZS6AKV

The various modes of VHF/UHF propagation will be discussed and methods that can be deployed to predict the likelihood of such conditions. If a long-distance VHF/UHF contact is made, what were the prevailing conditions and the use of this information in building a better forecasting system

11:00  Refreshment Break

11:30 Developing a reverse beacon network

Brian Jacobs ZS6YZ

The Reverse Beacon Network has evolved to become a powerful tool with many Amateur Radio applications, mostly on the HF bands.  The RBN concept also provides unique opportunities for real time propagation awareness on VHF and UHF. In this presentation Brian looks how beacons and spot VHF/UHF calling frequencies can be monitored from different sites and generate alerts when an opening occurs.  During his presentation he will demonstrate the concept with some practical examples

12:30  Update on currently operating beacons and a planned 2m beacon mid-way between Gauteng and the Western Cape

Dick Coates ZS6BUN

13:00 Open discussion:

1.     Could multiple  AMSATSA  dual band Yagis be used to monitor beacons from various areas at the same time and provide a real time opening report?

2.     How  to get clubs more involved in promoting VHF/UHF activity

3.     Will  regular short burst competitions promote more activity

4.     Setting up a telegram early propagation alert system 

14:00 end

Presentations from October 2018 workshop

The following papers are available for download

Beacon Coordination: Brian Jacobs ZS6YZ download here

Build a simple 3cm band transmitter (and receive it with an SDR receiver): Cor Rademeyer ZS6CR  download here

Operating on 23 cm and Aircraft Scatter: Rickus de Lange   ZS4A  download here






People registered attending the workshop
on 9 February 2019

Name Call Yagi
Brain Jacobs ZS6YZ Yagi
Anette Jacobs ZR6D  
Fritz Sutherland ZS6SF  
Carl Minne ZS6CBQ  
Hannes Scheepers ZS6EMS  
Marinus Brand ZS6BM Yagi
Hans van de Groenendaal ZS6AKV  
Dick  Coats ZS6BUN  
Nico van Rensburg ZS6QL Yagi
Koos Greyvenstein ZS6KSG  
Tobile Koni ZS6TKO Yagi
Matthew Varkevisser ZS6MDV Yagi
David Lloyd ZS6ACC Yagi
Kevin Fraser ZS6KB  

Why Radio Amateurs should be concerned about the rising RF noise levels?

Worldwide the RF spectrum use is continuing to grow as technology progressively makes more use of wireless connectivity. The spectrum has become steadily more polluted as the number of non-compliant and faulty pieces of electronic devices including substandard equipment has also risen over the years.

The reluctance and short- sightedness of regulators in various countries to act against manufacturers of non-compliant electronic devices and equipment, leaves the radio amateur fraternity with no other alternative but to get involved in collecting the necessary RF noise floor data and to support initiatives for proper interference regulation and action against radio frequency pollution on a world-wide level. 

On 15 June 2016, the FCC office of engineering and technology technical advisory council opened a noise floor technical inquiry in the form of ET docket no. 16-191 to seek answers to the following basic questions: 

·     Is there a noise problem?

·     * Where does the problem exist? Spectrally? Spatially? Temporally?

·     * Is there quantitative evidence of the overall increase in the total integrated noise floor across various segments of the radio frequency spectrum?

·     * How should a noise study be performed? 

Unfortunately, most feedback was anecdotal and not accompanied with measured quantitative data.  This is largely because the responders did not have the instrumentation resources nor the budget to provide the quantitative evidence being sought. Despite the scarcity of quantitative data submissions, one clear outcome of this TAC technical inquiry is an unmistakable consensus among the responders: A noise floor study is not only needed but long overdue. 

In the USA and spreading to Europe radio amateurs and scientists have joined forces in Ham Radio Science Citizen Investigation (HamSCI*), a collaboration between radio amateurs and scientists to advance scientific research and understanding through amateur radio activities. While the group is currently more focused on radio propagation, ionospheric studies and space weather, the concept would work well to make meaning full contributions to study the increases in the RF noise floor. 

It may sound complex but with the right software, a raspberry pi and a HF dongle it is very easy to create monitoring stations in many parts of the world, create a universal server where the data is upload and develop algorithms to review the data after a period of time.  

The SARL has a number of pilot stations operating and has configured a server to where the monitoring stations automatically upload their data. 

It is fully understood that there are issues, such as antenna and receiver calibration, that still need to be solved. Under the current pilot system each participating radio amateur can review his own data and monitor the changes in the RF noise level in his immediate area.  

The SARL is continuing to fine tune the software for the monitoring station. The diagram below illustrates the basic station setup