Shortwave in Brazil: Audio Comparison Between Analog (Conventional) and Digital (DRM) Transmission

This recording was made in the countryside of Ceará, Brazil, by Jonathas Oliveira, a radio amateur and shortwave enthusiast. He tuned in to a North American broadcaster that transmits simultaneously in both analog and digital (DRM) modes, providing a unique opportunity for a direct comparison between the two types of reception.

Using two receivers — one conventional and the other DRM-compatible — Jonathas captured the ambient audio of both transmissions. While the recording does not fully replicate the ideal listening experience (due to the ambient method), the video clearly highlights the differences between the two transmission modes, achieving its main goal: to demonstrate the leap in quality provided by digital radio.

The tests were conducted using only the telescopic antennas of both receivers. The analog frequencies 7,335 kHz and 7,365 kHz operate with 250 kW, according to information from the Skywave Schedules app. Meanwhile, the digital transmitter on the 7,345 kHz frequency operates at approximately 5 kW, based on information from the drm.org website.

Transmission QTH: Greenville, North Carolina, USA

Frequencies: 7,335 kHz, 7,345 kHz, 7,365 kHz

Transmission Power: Analog 250 kW, Digital 5 kW

Language: Spanish

Reception QTH: Choró, Ceará, Brazil

UTC Time: 17:00 to 02:00

Distance: 6,009 km

Receivers: Tecsun PL880 and Gospell GR-228 BP

Antenna: Telescopic

Shortwave transmissions allow for a technical flexibility that balances range and audio quality. In DRM, for instance, it is common for broadcasters to use lower bitrates and mono audio to ensure greater signal robustness over long distances. Although this may seem like a reduction in quality, it results in significantly increased stability, and still outperforms traditional analog shortwave audio.

In the specific case of the recording presented, the North American broadcaster maintained relatively high audio quality, making the advantages of DRM even more evident. Even with ambient capture, the digital audio is noticeably clearer, reaching a quality level similar to local FM, easily surpassing analog reception — even on medium wave.

This video also reinforces an important point: even without Brazilian stations currently broadcasting in DRM, purchasing a DRM-compatible shortwave receiver is not a wasted investment. DRM radio is, by nature, global. With such a device, listeners can tune in to transmissions from various parts of the world — and, depending on conditions and equipment, even experience notable reception on medium wave right here in Brazil.

Brazil has yet to establish any official incentives for purchasing DRM receivers — no subsidies, not even public awareness campaigns. Yet, we are already beginning to see individuals acquiring these devices and demonstrating their ability to receive multiple DRM broadcasts from around the world.

Naturally, those investing in this type of equipment so far belong to the expected audience: enthusiasts, radio amateurs, and broadcast professionals. While it’s not yet a widespread movement, these pioneers play a crucial role — they are, in practice, our real test pilots.

Thanks to their efforts, we now have access to valuable observational material, with recordings that enable real-world technical analysis, simulations, and adjustments — providing a clearer picture of how the system might perform on a larger scale, should DRM be officially adopted across the country.

Watch on Jonathas Oliveira DX’s channel:https://www.youtube.com/@Jonathas104

See also: Crucial Adjustments to DRM Receiver Models to Win Over the Brazilian Audience