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.