Thursday, December 31, 2020

AlgorKorea creates innovative DRM solutions

After having seen some DRM enthusiasts posting reception reports using the AlgorKorea’s DRM receiver software, I reached out to its CTO Dr. Soon Jarng for an interview.  


Tell us a little bit about yourself:

I got a bachelor's degree in electronics engineering from Korea, a medical master's degree in physiology from the UK and a doctorate degree in electrical and electronic engineering from the UK. I have been a professor of electronic engineering for more than 26 years at the engineering college in Korea, and am now focusing on the development of digital signal processing algorithms for hearing aids and firmware for microchips in the US.

What is your inspiration?

The desire to spread the gospel of Christ to the world through broadcasting was the motivation for the study, and the program is being developed with the talent and curiosity that God provides every day.

Please tell us more about AlgorKorea:

While serving as a professor in Korea, I had an opportunity to promote hearing aid research & development and commercialization, and I founded a company (AlgorKorea) and experienced extensive experience in manufacturing and selling hearing aids. After retiring as a professor and moving to the United States, I changed the type of hearing aid manufacturing and sales to the type of hearing aid core firmware and app development.

It is a type of business that supplies software to manufacturing companies that need hearing aid firmware and apps that we develop.

I had some knowledge of digital communication theory from my experience teaching communication engineering in the Department of Electronics Engineering. At the same time, continuous research was conducted on FM (Frequency Modulation) hearing aids and speech recognition/translation/synthesis as special hearing aids required for people with profound hearing loss or deaf.

How did you get involved in DRM application development?

After hearing that the Gospel is broadcasted all over the world through KTWR, we are volunteering that anyone who have a smartphone/PC and an RTL-SDR dongle to use free DRM decoding app (DRM+ SDR, DRM+ FM) or PC program (DRM4WIN). We want more than 600 million people around the world to listen and watch Christian broadcasts through our free app. In addition, in order to avoid the problem of paid patent license of DRM technology, OPUS encoder/decoder is used instead of the existing AAC encoder/decoder. To realize the OPUS encoder in the DRM field, a separate DRM content server called DRMTX4WIN (for PC) has been developed and distributed for free.

Instead of the existing FM hearing aids that deliver sound only in alternative schools for the deaf/hearing impaired, DRM broadcasting and reception technology has been applied as an effective method of delivering text, pictures, files, and the web in addition to sound.

Tell us about your software applications:


In 2019, we mainly developed smartphone apps (DRM+ SDR, DRM+ MSi, DRM+ FM) for receiving DRM broadcasts, and in 2020, intensively developed PC versions of DRM content server (DRMTX4WIN) and reception program (DRM4WIN).

DRM content server (DRMTX4WIN) is a program that generates DRM signals by inputting audio, text, pictures, files, and web, and receiving program (DRM4WIN) decodes DRM signals to sound, text, picture, file, and web.

Our DRM receiving app (DRM+ SDR, DRM+ MSi) can decode HE-AAC, xHE-AAC compressed signals, but the newly developed DRMTX4WIN, DRM4WIN and DRM+ FM apps only use OPUS encoding (compression) and decoding (decompression) function.

Although HE-AAC and xHE-AAC decoding technologies are already secured, if these technologies are used, the problem of patent licenses prevents DRM apps from becoming free and spreading all over the world. As a result, only OPUS decoding technology is being applied.

This is because, when considering consumers around the world, most consumers prefer free apps. DRM standard came out as a means to replace the existing analog radio broadcasting with digital radio broadcasting, but in the basic specification of compression and decompression of audio, the barrier of patent license is preventing the globalization of DRM broadcasting.

While conducting DRM-related research, DRM broadcasting technology can be applied not only to alternative FM hearing aids, but also to remote broadcasting education in areas where the Internet is not available. In addition to analog communication, digital communication can be applied to send and receive texts and files among amateur ham radio individuals.

What about your plans for DRM broadcast testing?

With this possibility in mind, we are planning to apply for the FCC's license in 2021 for pioneering educational broadcasts on the JAMA campus.

Can you give a brief description of JAMA and your connection to it?  

JAMA stands for Jesus Awakening Movement for America and aims to establish and operate a college that fosters Christian leaders. I am only praying for JAMA and there is no special connection. I've met the founder of JAMA several times. I want to try distance education through DRM broadcasting in Christian institutions such as JAMA, schools, churches, and organizations. DRM does not have a wide frequency band like DAB, so it has a limited transmission rate, but it can transmit text and files in addition to sound through an FM transceiver of a narrow frequency band, so it is expected to be used in areas without the Internet.

How can DRM enthusiasts and experimenters access your software and apps?

If you would like to know any other information about us, please send us your questions. DRM4WIN can be found here.

Thank you Dr. Soon Jarng for for an interesting and informative interview. I look forward to further DRM progress from AlgorKorea.


Saturday, December 5, 2020

VOACAP plots for Rádio Nacional da Amazônia DRM Test

Brother Zyg has graciously provided us with VOACAP plots for the ongoing test. We are starting here with 20:00 UTC.Thanks Zyg! 








Wednesday, November 25, 2020

Rádio Nacional da Amazônia is on air with DRM on 11910 kHz


EBC & Brasília University running tests now on 11910 kHz DRM kHz from the transmitter site at Parque do Rodeador. Currently it is operating an average power of 1.12 kW into an HRS dipole curtain 4/4/0.5 at azimuth 320 degrees.

See previous post for further details. 







Saturday, November 21, 2020

A New HF Station that's Similar, but Different

By Bennett Kobb

On October 21, 2020, DPA Mac LLC filed a FCC license application for a new, DRM-based International Broadcast Station to be located in Maple Park, IL. The principal is San Francisco entrepreneur Seth Kenvin and its technical consultant is Tamir Ostfeld of Raft Technologies, an Israeli developer of low-latency HF systems for so-called algorithmic trading.

No station devoted to algorithmic trading has ever been authorized for regular commercial operation in the U.S., as there is no formal radio service or spectrum allocation for that purpose. Several such stations have been licensed in the Experimental Radio Service (ERS), which is ostensibly for scientific studies only.

If the FCC licenses DPA Mac, it will be the first such station to make the transition from the ERS to regular, non-experimental licensing. This station would be the successor to experimental station WI2XXG. Other than the license document, the FCC has withheld most of WI2XXG's records from public disclosure since it was first licensed in 2017.

DPA Mac is similar to other DRM stations on which we previously reported: WIPE in Alpine, NJ, which is built and is waiting on its FCC license; and WPBC, proposed for Batavia, IL. With regard to their use for non-broadcast, private data transmissions, those stations made general and non-descriptive representations to the FCC. On the other hand, DPA Mac's license application is fairly transparent. The station aims to transmit "investment data from points within the United States to locations outside the United States carried over a channel immediately adjacent to the HF broadcasts...a low-power, low-latency digital data transmission service provided to private investors, including small- and medium-sized firms."

This service "will provide the necessary financial support to deploy and sustain the HF broadcasting business for the benefit of the public now and into the future." The data component, it said, will fund an "over-the-air, commercial-free audio broadcast of U.S. financial news and similar information to populations outside of the United States that have access to a standard, commercial, off-the-shelf HF receiver."

Waivers of FCC rules

DPA Mac requested waivers of certain FCC rules. Its station would run 2 kW transmitter output power, while Rule 73.751(c) requires a minimum mean power of 10 kW if digital modulation is used. "Technological advances have rendered a minimum power requirement obsolete," the company said, "and DPA Mac's technological showing demonstrates that it can successfully operate at a much lower power of 2 kW. Operating at this lower power will increase the efficiency of transmissions and reduce the likelihood of harmful interference to adjacent band operations, allowing DPA Mac to maximize use of this spectrum."

One of its proposed eight frequency bands is 7.342-7.4 MHz, which is not available to International Broadcast Stations. Footnote US136 to the Table of Allocations restricts use of 7.3-7.4 MHz to certain fixed, land mobile and maritime mobile stations. Another FCC rule, 73.702(j), concerns assignment of one frequency for use at a time, while DPA Mac said its "lower power transmissions are more susceptible to disruption from atmospheric changes and other source[s] of interference than traditional high-power transmissions are. To overcome these challenges without raising power, DPA Mac may need to use more than one frequency at any given time to maintain a continuous, uninterrupted connection to listeners."

The company also requested a limited waiver to give it more time to find a location for an auxiliary transmitter. "DPA Mac is immediately able to broadcast its programming to the foreign public using its main transmitter," it said. "Auxiliary transmitters provide a back-up means of transmission but are only necessary in rare circumstances."

Looking ahead

The FCC rules for International Broadcast stations don't accommodate non-broadcast data communications to private customers. All such transmissions, including "datacasting", are limited to broadcasts for reception by the general public - at least until the FCC changes the rules, ignores non-public communications as insignificant, or interprets or waives the rules to allow them. DPA Mac's application is the third to propose such operations, and is certainly the most explicit.

In addition, if the FCC allows a reduction in minimum power from 10 kW to 2 kW, it could improve the economics of private shortwave broadcasting considerably. Perhaps the FCC could reduce the costly 50 kW AM minimum power as well.

What is certain is that the FCC can't sit on these license applications forever. Someday these new DRM stations will go on the air, and perhaps even change the face of private U.S. shortwave broadcasting.