# Simulation of the Earth's radio leakage from mobile towers as seen from selected nearby stellar systems

**Authors:** Ramiro C. Saide, Michael A. Garrett, Nalini. Heeralall-Issur  
**arXiv:** [2304.13779](https://arxiv.org/abs/2304.13779)  
**Date:** 2023-04-26  
**Summary page:** https://www.summarizepaper.com/en/arxiv-id/2304.13779v1/

## Key points

- Earth's radio leakage has changed significantly since 1978.
- Cable TV and internet have reduced powerful TV transmissions as a contributor to Earth's leakage radiation.
- Mobile communication systems are now a new and growing component of the Earth's human-generated radio emission.
- There are currently 7.26 billion mobile phone users worldwide, with mobile towers spread across the planet's landmass generating radio transmissions at frequencies within or close to L-band, a major band for radio astronomy.
- No previous research has investigated the cumulative effect of mobile tower emissions on eavesdropping and SETI more generally.
- The paper investigates how radiation leakage from mobile towers on Earth would appear if viewed by an extraterrestrial civilization using instrumentation similar to our current radio telescope technology.
- The model grids the planet's surface into small regions that rise and set as the Earth rotates, resulting in a dynamic power spectrum of the Earth summed over all cellular frequency bands.
- Preliminary results demonstrate that peak power leaking into space from mobile towers is approximately 4GW, associated with LTE mobile tower technology emanating from East Coast China as viewed from HD 95735.
- The study provides insight into what we might expect if there is human-like civilization located elsewhere in Milky Way with similar or more advanced levels of radio telescope technology.
- The paper plans to extend its model to include additional sources of leakage radiation such as ground-based uplinks, various types satellite services, and low Earth orbit constellations such Starlink or OneWeb.

## Summary

The Earth's radio leakage has undergone significant changes since the pioneering work of Sullivan et al. (1978) over 40 years ago. With the rise of cable TV and the internet, powerful TV transmissions are no longer a major contributor to the Earth's leakage radiation. However, mobile communication systems, which were unknown until the 1990s, currently represent a new and still growing component of the Earth's human-generated radio emission. According to Statista (2022a), there are currently 7.26 billion mobile phone users worldwide, suggesting that over 91% of people in the world own cell phones. These individual handsets are serviced by a vast network of mobile tower systems spread across the planet's landmass. Although each tower generates radio transmissions with relatively low power levels (hundreds of watts), their directivity and sheer numbers make them a significant component worthy of further study. Mobile towers transmit at frequencies within or close to L-band, a major band for radio astronomy that includes the "water hole" defined by natural emissions from HI and OH at 𝜆 = 21cm and 𝜆 = 18cm (Oliver & Billingham 1971; Siemion et al. 2010). As far as we know, no previous research has investigated the cumulative effect of mobile tower emissions and its implications for eavesdropping and SETI more generally. In this paper, we investigate how radiation leakage from mobile towers on Earth would appear if viewed by an extraterrestrial civilization using instrumentation similar to our current radio telescope technology. We calculate the overall radio power spectrum of the Earth and associated detection limits for several different exoplanet systems while analyzing future evolution using 5G towers as a proxy. We model mobile communication towers using publicly available data on their locations and assume a simple integrated transmission pattern for their antennas. The model grids the planet's surface into small regions that rise and set as the Earth rotates, resulting in a dynamic power spectrum of the Earth summed over all cellular frequency bands. Our preliminary results demonstrate that the peak power leaking into space from mobile towers is approximately 4GW, associated with LTE mobile tower technology emanating from East Coast China as viewed from HD 95735. We explore detectability of these emissions assuming a range of different instrumentation including next-generation telescopes such as SKA (Square Kilometre Array). Our study provides insight into what we might expect if there is human-like civilization located elsewhere in Milky Way with similar or more advanced levels of radio telescope technology. In conclusion, this paper presents an investigation into overall power contribution of mobile communication towers to Earth's radio leakage budget and its implications for eavesdropping and SETI research more generally. We plan to extend our model to include additional sources of leakage radiation such as ground-based uplinks (including Deep Space Network), various types satellite services and low Earth orbit constellations such Starlink or OneWeb in order to gain better understanding about potential signals coming from outer space which could be detected by modern day instruments like SKA telescope array system .