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High Frequency and Single Side Radios


What is it Today?

HF/SSB radio operates in the lower end of the commercial AM frequency spectrum (1.8 to 30 MHz). Its major characteristic is very long radio wave lengths that can reflect off a belt of charged particles girding the earth called the ionosphere. Until recently, highly trained and experienced operators were required to properly install and operate bulky and temperamental analog HF/SSB radios. But with the development of Digital Signal Processors (DSP), Automatic Link Establishment (ALE) programs and Near Vertical Incidence Antenna Systems (NVIS), the Micom 2E is as easy to operate as a cellular phone. Today's communications officers need only to program their assigned frequencies and individual station names into the radios upon receipt of their equipment. This just like programming the phone numbers and names of friends and relatives into the speed dial of a cell phone. The DSP will manage the system from that point forward.


What is the DSP Managing?

As the ionosphere constricts and expands from daytime to nighttime, ideal frequency programming should include long, medium and shorter length frequencies within the HF band. This frequency variation is required to compensate for the changed geometric angle between points A and B caused by the expansion and constriction of the ionosphere.

The Automatic Link Establishment feature within the DSP determines which is the best operating frequency for that time of day by establishing and maintaining automatic link quality assessments among all the stations within the network. No longer is a highly trained operator required to read periodic logs, twist dials, clip antennas and adjust antenna reflected power to establish and maintain loud and clear communications paths. It's all done by software. ALE is now governed by a federal standard (FS-1045) that requires that all competitor HF/SSB radios equipped with ALE be compatible with all others so equipped. Therefore, should an itinerant HF/SSB radio need to be included in a programmed net, it could be allowed for the duration of an operation. ALE also provides a squelch feature that cancels the white noise, or annoying background noise, common to all AM radios.


What About Range?

Normal fixed station antenna propagationHF/SSB AM radios are capable of transceiving short signals +/- 35 miles from a whip antenna somewhat the same as higher frequency VHF-FM and UHF-FM systems operate. This is known as surface wave or line of sight (between the radios) communications. But HF/SSB is better known for transmitting very long-range signals over thousands of miles by skipping its signal off the ionosphere (sky waves). Until recently there had always been a dead space of roughly 35-110 miles between the surface wave range and the sky wave range.

 

 


Normal Fixed Station Antenna Propagation

NVIS fixed station antenna propagationThe U.S. Army found this operational shortcoming to be unacceptable. During the last several years a technical project team from the USACECOM, Ft. Monmouth, New Jersey, developed what is now referred to as "the poor man's satellite system" or NVIS (neh-vis). In short, the NVIS antenna shoots a signal near vertically up to bounce down off the ionosphere providing an uninterrupted footprint from ground "0" to a radius of 3,000 miles and more. Adjusting the radials, or wire arms, of the antenna will constrict or enlarge the required operational area of coverage.

 

 


NVIS Fixed Station Antenna Propagation

Vehicles operating in this area can take advantage of the NVIS system by securing the tip of their whip antennas to a horizontal position. Perpendicular radiation off the length of the whip antenna will transceive directly from the ionosphere which has been flooding valleys and canyons with sky waves transmitted by the NVIS antenna sites. With its low cost and no air time charges, the Micom HF/SSB radio/NVIS antenna system has become the "poor man's satellite system."


What Else Can the Micom HF/SSB Do?

Because the Micom is a digital or software defined radio, it is fully capable of sending and receiving email (@ 300-9600 baud) and fax, conducting automatic vehicle location (AVL) mapping and interrogation, telemetry interfacing, telephone interconnect and voice interconnect with VHF-FM, UHF-FM, 800/900MHz-FM and weather alert radios.

The Micom 2E is fully compatible with HAL clover 2000 modems (300-2400 baud), RF Harris serial tone and 39 tone modems (2400-4800 baud), and Rockwell Collins (9600 baud) modems. As there is no federal standard yet in place governing interoperability among competing HF email systems, Rockwell Collins has emerged with the only system to date that is based upon the NATO Standard STANAG 5066 which is expected to become the foundation for the new US HF email standard.

The Micom 2E is also compatible with AN/DVT encryption (classified), Rockwell Collins VP-116 Voice Privacy encryption with over-the-air re-keying (OTAR)(DES/DVP level) and TCC Secure Voice Encryption (unclassified). These unclassified encryption options offer high-level security from meddlesome media scanners as well as from other unwanted and unwelcome eavesdropping.


Current Application Notes

Email Operation — CDC Response Teams will be utilizing high speed (9600) wireless email systems to access regional and national logistical files from disaster areas where phone lines have been disrupted or totally lost.

Automatic Vehicle Location — The United States and South American host governments are electronically map tracking over 320 drug interdiction riverine patrol boats operating throughout the Amazon basin utilizing the Micom 2E AVL feature.

Telemetry Operation — A pipeline and wellhead management company from Oklahoma is implementing a long haul telemetry system, which will transmit and receive wellhead and pump station data and commands to and from their seven regional offices throughout the United States.

Telephone Interconnect — The New York Army National Guard group used the Micom Astic (automatic telephone interconnect) to remotely access their securely placed Micom PABX connected radio in Albany, New York, in order to communicate via telephone with the New York Port Authority Police (controlling ingress and egress from Manhattan) and to access other disaster relief agencies telephones. The HF system became the National Guards forward EOC long distance telephone system (with no corresponding long distance fees).

Interlink Interface — US Army National Guard disaster response teams as well as the FEMA sponsored Urban Search and Rescue teams are using the Micom Interlink as a voice patch between their Motorola FM handi-talkies and the Micom AM HF/SSB in order to communicate from the disaster site directly to their remote higher headquarters. This was exemplified in the WTC response effort.


Possible Anti-terrorist Applications:

1. Terrorist Event Backup Communications — When telephone lines might fail, the Micom 2E has and will continue to provide a communications link.

2. Direct Coordination With Other Disaster Response teams — HF is the only common frequency band for federal government, state & local government and industry (utilities, etc) inter-communications.

3. AVL Fleet Safety Tracking — wide-area fleet map tracking in normal, foul weather and disaster recovery conditions.

4. Telemetry — wide-area low speed (@4800) data transmissions for reporting, switching, alarm and control.

5. FM Radio Interlink — utilize existing VHF-FM or UHF-FM radio assets to wide area voice remote through the Micom 2E wide-area radio.

6. AM Radio Interlink — audio patch the national weather alert and early warning radio networks through the Micom 2E wide-area radio.

7. Email Operations — wide-area file transfers recurring reports and schedules.

8. Fax Operations — wide area transmissions of signatory documents.

9. VP-116 Voice Encryption — keep scanner monitoring security threat media and individuals from monitoring time-sensitive communications.

10. National, State and Local Disaster Coordination — wide-area disaster response coordination on a common frequency band (if not the only) available to all critical industries and government agencies.

 

 

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