February 2003

AMERICAN RADIO ALLIANCE                                                             ADDENDUM “A”.
Special Report No. 69~A                                                                                 June 1993
 
FOREWORD

This shorter version of Addendum "A" summarizes methods used to capture data for our SIGNAL ANALYSIS project This work provided the data upon which the overall Study was based. Covering the 20 Meter Band, with special interest in the 14.160-14.350 kHz US. Single SideBand (SSB) segment plus a "target" area of 14.225-14.235 kHz, the project includes data for fifteen months of on-frequency monitoring, spread over several years.

This section explains how we have rationalized Theoretic versus Idealistic space available for Amateur operations. A concept known as Communications Success Level (CSL) is introduced so that we may have a way to measure and express the relative usefulness of a Ham Band under certain conditions.

For example, a CSL of 88-98% is possible when signal density (SD) is 3 Channels per 10 kHz. A Signal Density of 4 Channels per 10kHz has a CSL of 75-85%. These figures assume all stations present are on the Primary Path which means they rank as the most dominant signals heard at the time. The variables of Skip/Propagation and Path Quality are important factors, of course.

When all stations are operating SSB Voice, assuming they use only their legal power and bandwidth, theoretically, 4 stations on the Primary Path could communicate with other stations. Unfortunately, a majority of the stations exceed their legal bandwidth due to a number of problems, some because of Operator error or willful neglect and others due to faulty or non-compliant equipment.

The Slow Scan TV mode was extensively observed in the 'target"' area and it was quite clear SSTV cannot compete with SSB Voice stations. The video modes (which use line scan technique) are especially vulnerable to interference. The need for locating SSTV activity in a less competitive part of the Band is clear. Obviously, no matter where they operate, malicious interference by malicious operators will continue unless FCC resumes its monitoring work. However normal interference (QRM) caused by stations looking for space in the General Class area would be minimized or eliminated.

Another insight from this project is the realization that regulations that force operators to collect in "hotspots" such as 14.225-14.235 kHz segment, should be revised to create Particular Usage channels. This approach would designate certain parts of the spectrum for a particular kind of communications.

For example, any Class licensee seeking to make a third party (telephone) contact would be permittd to use a designated channel for that particular contact. Such traffic would have Priority Status on that channel. The idea is to reduce the amount of searching for a spot for contacts OTHER than random QSOing and DXing. Presently, powerful stations, usually engaged in DXing, dominate the Bands and those with other interests cannot find space. This situation has driven many operators into the 14.230-233 kHz sector, turning it into a UTILITY area.

The use of Particular Usage channels would serve to mediate the over-dominance of DXers whose high power and aggressive behavior makes them Top Dog. The FCC would control the number and type of Particular Usage channels designated. This approach, or a similar strategy, is needed to assure "equal access" for all Amateurs. Such channels when located at the channel (3-5 KHz wide) that separates Extra, Advanced and General Class segments would serve as Rendezvous points for operators to meet on a schedule after which they are required to QSY to an open channel elsewhere. 

Today's regulations fail to address problems faced by lower power (portable and mobile) stations.

The graphs in this section are examples taken from a larger group. Please read SAMPLiNG THEORY and CRITERIA and STANDARDS and DEFINITIONS which follow. 

 ***** Note the section on ANALYZING GRAPHS which will help you to interpret the graphs. *****
 

GO to Plotted GRAPH #1 (only one graph is provided as an example)