A Simplified Sounding System for Finding NVIS Channel Availability to Support Government Radio Networks in Indonesia

  • Titon Dutono Politeknik Elektronika Negeri Surabaya (PENS)
  • Zulmi Zakariyah Politeknik Elektronika Negeri Surabaya (PENS)
  • Tribudi Santoso Politeknik Elektronika Negeri Surabaya (PENS)
  • Denny Setiawan Ministry of Communication and Information
Keywords: WSPR, beacon, ITU-R, ionosphere, RTCE


Mostly  natural disasters in Java Island such as landslides are within the vicinity of not more than 200 Km from the district capital. Cellular communications require complex systems and rather vulnerable  to cope with disasters. NVIS mode is considered as a simple radio link during disaster mitigation initiation process. It needs a valid estimation to figure out the condition of the ionosphere. There are two purposes of this study, the first of which is an attempt to find out a fact the existences of authorized HF users who still work in the band of 3 MHz – 10 MHz.  The second is to integrate low cost HF radio communication, commonly available small single board computer hardware, and opensource software, to build a sounding system to evaluate the quality of NVIS channels. Prediction system such VOACAP give hourly prediction data, however it has an inherent limitation because of   nature the underlying databases is monthly average based, therefore, the estimation could not be made in a daily bases. However, a real-time channel evaluation (RTCE)  able to purify maximum observed frequency (MOF) estimation, and consequently, its able to select the best available frequency for short term  and real time operation. In this study, we used WSPR to perform a simple RTCE technique. Furthermore, we also reviewed the current regulatory status regarding  the availability of sub-10 MHz band for NVIS radio operation. The results show that discrepancies between simulation and measurement are occurred mainly because of sporadic data in the band of 60m and 80m. However, all of the measurement results and simulations almost have the same agreement regarding the quiet period between local midnight and local sunrise. The results of measurements show that 60m band is the most reliable NVIS channel between local sunrise and local midnight. Furthermore, 100 watts is a proper transmitter power to reach the required SNR for reliable voice communication.


Author Biographies

Titon Dutono, Politeknik Elektronika Negeri Surabaya (PENS)
Lecturer of PENS
Zulmi Zakariyah, Politeknik Elektronika Negeri Surabaya (PENS)
Graduate student of PENS
Tribudi Santoso, Politeknik Elektronika Negeri Surabaya (PENS)
Lecturer of PENS
Denny Setiawan, Ministry of Communication and Information
Deputy Director General for Spectrum Policy and Planning


Witvliet A Ben, Alsina-Pages Ma Rosa, Radio Communication via Near Vertical Incidence Skywave Propagation: an overview, Telecommunication Syst, Springer, Online, Feb, 2017.

Maslin Nicholas, HF COMMUNICATIONS: A SYSTEMS APPROACH, Pitman Publishing, pp. 63, 1987.


ITU-R, Radio Regulation (RR), Article 5, Frequency Allocations, 2012.

Law of The Republic of Indonesia On Telecommunication No.36 year 1999, Article 33, 1999.

ITU-R, Radio Regulation (RR), Article 5, Frequency Allocations, 2015.

Walden C Marcus, Comparison of propagation prediction and measurements for midlatitude HF near-vertical incidence sky wave link at 5 MHz, RADIO SCIENCE, VOL. 47, RSOL09, 2012.

Zolesi Bruno, Cander R Ljiljana, Ionospheric Prediction and Forecasting, Springer Geophysics, p.185, 2014.

Lane, G., Signal-to Noise Prediction Using VOACAP - User’s Guide, Rockwell-Collins, Cedar Rapids, Iowa, 2001.

ITU-R, Recommendations P. 533-13, Method for the prediction of the performance of HF circuits, 2015.

Stocker A J., Fast and accurate calculation of multipath spread from VOACAP prediction, RADIO SCIENCE, Vol.47, RS 4005, 2012

Witvliet A Ben, Maanen van Eric, Peterson J George, Measuring the Isolation of Circularly Polarized Characteristic Waves in NVIS Propagation, IEEE ANTENNAS & PROPAGATION MAGAZINE, June, 2015.

Dutono Titon, Ikeda Naomitsu, Watanabe Akira, Effect of Compound parameters on speaker-independent word recognition, J Acoustic Soc Jpn (E) 19, 1, pp 1-11, 1998.

Dutono Titon Et al., A Spot Independent for NVIS Channel Observation, Proceeding of IES-ETA, Bali, pp. 247-251, 2018.

Gokya S Nicols, Understanding Propagation using WSPR to Gauge Propagation, RSGB Propagation Studies Committee, RADCOM, 2009.

ARRL, Antenna Handbook 2007, ARRL Publisher, Chapter 7, 2007.

ITU-R, Recommendation ITU-R F.339-8, Bandwidth, signal-to-noise ratios and fading allowances in HF fixed and land mobile radiocommunication systems, 2013.