New Android App for decoding DRM digital radio broadcasts

 

On the 13th of April 2021, a company named StarWaves announced the release of a new Android app called DRM SoftRadio. The app allows a user of a Software Defined Radio (SDR) to listen to any DRM digital broadcasts on an Android smartphone or tablet.

DRM or Digital Radio Mondiale is the global digital radio standard used for digital transmissions on medium wave and short wave in several countries. 

Some of the features...

Languages: English, German, Simplified Chinese

Convenient frequency tuning and DRM Service selection

Journaline, DRM’s advanced text application, allows to interactively browse through latest news, sports and weather updates, programme background information and schedules, distance learning/RadioSchooling text books, travel information, and much more

Free tuning to any DRM broadcast frequency

Supports all DRM frequency bands – from the former AM bands (LW/MW/SW) to the VHF bands (including the FM band), depending only on RF dongle functionality

Graphical spectrum view to check the signal on the tuned frequency

For live reception, an SDR RF dongle must be connected to the device’s USB port (with USB host functionality). The following SDR RF dongle families are currently supported, along with a range of specifically tested models:

Supported SDR receivers...

Airspy HF+ family: Airspy HF Discovery, Airspy HF+ (Dual Port). (Note: Airspy Mini and R2 are NOT supported.)

SDRplay family: SDRPlay RSP1A, SDRPlay RSPdx, SDRPlay RSPduo, SDRPlay RSP1, SDRPlay RSP2, SDRPlay RSP2pro, MSI.SDR Panadapter (Note: SDRPlay family support on Android is currently limited to the 32-bit version of this app.)

RTL-SDR family: The experimental support for RTL-SDR based RF dongles requires that you manually start the following separate tool before opening this app (on standard port ‘14423’): The app ‘SDR driver’ can be installed from the Google Play Store and other Android app stores.

Analysis... While DRM (Digital Radio Mondiale) has been around as a digital radio standard since 2003, it has proved difficult to get accepted by broadcasters and the general public. Broadcasters were unwilling to use DRM due to a lack of suitable receivers and the public weren't interested because there were a lack of DRM transmissions.

That has changed of late with the introduction of DRM transmissions in the medium wave band in India. Considering its population, it is assumed that this will kick off the development of cheaper DRM receivers.

While SDR receivers are probably used more by those interested in technology and radio rather than the general public, this new app does open up DRM transmissions to a whole new audience.

The app costs in the region of €5/$5 which is very modest for most SDR users.

It is my understanding that a Windows version is being developed by the company and this should be of interest to an even wider audience.

Links...

1) StarWave news release - 13th April 2021

2) Google Play Store

3) Official DRM website

Video: Unusual signals heard on the VHF & UHF bands with a radio scanner

 

As radio systems gradually migrate from analogue to digital technology, more and more unusual commercial and non-commercial signals can be heard on the VHF & UHF radio bands.

Lewis M3HHY in Manchester has a very popular YouTube channel where he puts up well scripted and presented videos about a wide range of radio related subjects. He recently put up two videos about some of the digital radio signals that can be heard on the VHF & UHF bands.

Video 1... 

Signals...

1) POCSAG ...Wide area paging.
2) MPT-1327 ...Trunk radio communication networks. 
3) Commercial DMR ...digital communications.
4) Car Key Transmitters
5) TETRA ...TErrestrial TRunked RAdio
6) Temporary Traffic Lights
7) Autocab ...Radio dispatch system
8) TPMS ...Tyre Pressure Monitoring Systems
9) Multitone Paging
10) dPMR ...Digital Private Mobile Radio (446 MHz)

Video 2...

Signals...

1) FLEX ...Flexible Wide Area Paging Protocol
2) VOR ...Very High Frequency Omnidirectional Range (108-118 MHz)
3) DAB Radio ...Digital Audio Broadcast
4) DSTAR ...Digital Smart Technology for Amateur Radio
5) NXDN ...Next Generation Digital Narrowband
6) Motorola Type II ... Paging Control Channel
7) Wi-Fi ...802.11N
8) System Fusion ...Yaesu Amateur Radio Digital Mode
9) LTE ...Long Term Evolution Network (4GLT / E-UTRA - Evolved Universal Terrestrial Radio Access). Mobile phone data.
10) AFSK ...Audio Frequency Shift Keying (Paging)

For additional information on unusual signals, visit this website... https://www.sigidwiki.com/wiki/Signal_Identification_Guide

Successful DRM tests on the FM band (88-108 MHz) in Russia

 

DRM (Digital Radio Mondiale) has long been touted as a possible replacement for the analogue AM and FM modes on the radio broadcast bands. The transition to digital has proved problematic as broadcasters and listeners are happy to continue with the status quo, especially on the 88-108 MHz FM band.

While many countries have opted for DAB and DAB+ transmissions on the VHF Band 3 (175-225 MHz), some countries are looking at the option of using DRM transmissions in the spaces between the FM signals on the 88 to 108 MHz band.

From June to December 2019, a sixth month trial DRM transmission was carried out in the Russian city of St.Petersburg. The 800-watt DRM transmitter was on 95.7 MHz between the FM radio stations Studio 21 at 95.5 MHz and Comedy Radio at 95.9 MHz. 

The main audio source for the trial was the Comedy Radio, which was broadcasted simultaneously as an analogue FM service (3KW) and a DRM service (0.8KW). This allowed a direct comparison to be made between the analogue FM and DRM coverage.

The results of the trial were publish in December 2020 in a paper titled..."RESULTS OF THE DRM SIMULCAST FIELD TRIAL IN FM BAND IN THE RUSSIAN FEDERATION... June to December 2019"

Some of the main conclusions were as follows...

The trial has shown that for DRM Simulcast with frequency offset of 150 kHz, DRM digital signal does not interfere with the analog FM signal at a power difference up to -10 dB.

For a frequency offset of 200 kHz, the digital DRM signal does not interfere with the analog FM signal at any power values that the transmitter could provide.

Because DRM Simulcast allows to keep FM broadcasting and launch terrestrial digital radio broadcasting in the same frequency range. DRM multiplexes can be launched between existing FM radio stations without interfering with them. To do this, it can use one transmitter and existing combiner and antenna system.

20:1 Digital Power Advantage... In separate tests done in Indonesia, it was claimed that six test points covered by the 1 kW transmitter (FM) could be served with only 50 watts of DRM power. “In testing a simulcast broadcast using 1 kW and 800 Watt with spacing distance 150 kHz between the middle frequency FM and DRM, the measurement showed no interference between FM and DRM. The DRM quality was at least equally good to FM, but the sound quality of DRM was even better than FM.”

In an article titled "Use DRM on India’s FM Band", the chair of the of the India chapter of the DRM Consortium Yogendra Pal stated..."Using DRM, in the allocated 200 kHz bandwidth, a broadcaster can transmit up to six high-quality audio services along with a host of value-added services and Emergency Warning Functionality (EWF). All digital services work without disturbing the existing analog FM services."

He also claimed that mobile phones that used for listening to analogue FM transmissions can also be used for listening to DRM transmissions as long as manufacturers allow the DRM app to access the baseband digital output.

"DRM standard can be supported natively on all mobile phones based on the already available tuners for analog FM reception. No additional hardware and, therefore, no additional design or component cost is required to enable DRM digital FM support on these phones.

The DRM App for mobile phones has already been developed and demonstrated by a number of organizations. Only the mobile phone manufacturers need to provide access of the baseband digital output. "

In summary... A lot of the information shown above is from the DRM industry who obviously want to push the new digital standard. However, the tests of using DRM on Band 2 (88-108 MHz) do suggest that there are more options than just setting up a new digital broadcast band elsewhere on the VHF spectrum. There are spaces in the FM band (88-108) and DRM can utilise those gaps.

Band 2 also tends to have mush better mobile coverage than the higher VHF bands around 200 MHz which are used for DAB transmissions and many listeners already have dedicated aerials for the 88-108 MHz band.

Transmitting DRM on Band 2 is also an attractive option for broadcasters in that they can use the same antennas and infrastructure. It provides them with an obvious path to gradually migrate to digital only services in the future.

New DMR repeater EI7FXD now operational in Cork - Dec 2020

The good news radio wise locally is that a new DMR repeater on 70 cms is now on air near Cork City in Ireland. It is co-sited with the existing EI7FXR analogue FM repeater at Farmers Cross near Cork Airport.

The callsign of the new digital repeater is EI7FXD and it has an output frequency on 430.250 MHz The input is 9 MHz higher on 439.250 MHz. This configuration is usually designated as DVU-R20.

The colour code is 1.

The Brandmeister ID of the repeater is 272015 should anyone wish to monitor the Brandmeister dashboard and hoseline.

Info from the Southern Ireland Repeater Group - DMR repeater for Cork City

A new 70cms DMR repeater was installed at Farmer's Cross near Cork city on Monday December 21st to provide DMR coverage to Cork City and surrounding areas. The set up consists of a Motorola DR-3000 repeater and the antenna is a CAT-C440 @ approx 50ft. It's the fourth digital repeater set up by the Southern Ireland Repeater Group and will complement our other three digital installations located at West Waterford, Waterford City and Mt. Leinster.