RTL-SDR for UTC Time in the Tropical Rainforest


In order to take an accurate sextant sight, we need to have precise time, ideally within 1 second. The Earth revolves at 360deg/24hours = 15deg/1hour = 15min_arc/min_time = 1min_arc = 4secs_time. A shortwave receiver can be used to get this time using international time stations.

WWV UTC Shortwave Time Station

Fig.1 NIST UTC Time Interface
Fig.2 RTL-SDR with HamItUp 125MHz Converter
Fig.3 Tropical Iguana Listens to WWV

In Toronto, time stations CHU Ottawa (Ref.1) or WWV Boulder Colorado (Ref.2) can be received. CHU transmits on 3.33MHz/7.85MHz/14.67MHz and WWV on 2.5MHz/5.0MHz/10MHz/15MHz/20MHz/25MHz (experimental). In Costa Rica, WWV can be received. Figure.1 shows the web interface of NIST the US Government agency that runs WWV. Figure 2 shows the receive setup of the RTL-SDR version 2 receiver with HamItUp HF converter (Ref.3). Figure 3 shows one of the local residents listening to the broadcast.

Fig.4 YouTube Video RTL-SDR en la Playa

Please send your comments, questions and suggestions to:


#1. – “NRC Shortwave Station Broadcasts CHU”

#2. – “Radio Station WWV”

#3. – “RTL-SDR for HF 0-30MHz”

Categorized as Navigation

By Jeremy Clark

Jeremy Clark is a Senior Telecommunications Engineer and Advanced Amateur Radio Operator VE3PKC. He is the author of E-Books on Telecommunications, Navigation & Electronics.