Naio90
Federal Republic of Ethiopia
- Jul 1, 2018
- 4,311
| TYPE | Infrastructure |
| COUNTRY | Argentina |
| PROJECT | VLF Broadcasting Stations |
| PROJECT COST | 200,000,000.00 |
| COMPLETION DATE | 20/02/2019 |
| PROJECT INFORMATION | Construction of three very low frequency broadcasting stations to communicate with argentine submarines. The stations will be located strategically positioned to obtain the most efficient communication with argentine submarines operating in the South and North Atlantic Ocean and Mediterranean Sea. They will be placed in: - Near Brusque, Santa Catarina. - Near Puerto Deseado, Santa Cruz. - Near Alexandria, National Territory of Alexandria. VLF radio waves (3–30 kHz) can penetrate seawater to a depth of approximately 20 meters. Hence a submarine at shallow depth can use these frequencies. A vessel more deeply submerged might use a buoy equipped with an antenna on a long cable. The buoy rises to a few meters below the surface, and may be small enough to remain undetected by enemy sonar and radar. Due to the low frequency, a VLF broadcast antenna needs to be quite large. In fact, broadcasting sites are usually a few square kilometres. This prevents such antennas being installed on submarines. Submarines carry only a VLF reception aerial and do not respond on such low frequencies, so a ground-to-submarine VLF broadcast is always a one-way broadcast, originating on the ground and received aboard the boat. If two-way communication is needed, the boat must ascend to periscope depth (just below the surface) and raise a telescopic mast antenna to communicate on higher frequencies (such as HF, VHF, or UHF). Low frequency communications are generally at 10kHz or lower. The penetration depth in seawater is only a few meters, and a very long antenna wire is required to float near the surface. All this would be done secretly. |
| PRIVATE / ENCRYPTED | Yes |
