Research with consumers and industry
in the Bathurst and Central Tablelands regions of NSW
march 2011
Canberra
Purple Building
Benjamin Offices
Chan Street
Belconnen ACT
PO Box 78
Belconnen ACT 2616
T +61 2 6219 5555
F +61 2 6219 5353 / Melbourne
Level 44
Melbourne Central Tower
360 Elizabeth Street Melbourne VIC
PO Box 13112
Law Courts
Melbourne VIC 8010
T +61 3 9963 6800
F +61 3 9963 6899 / Sydney
Level 15 Tower 1
Darling Park
201 Sussex Street
Sydney NSW
PO Box Q500
Queen Victoria Building
NSW 1230
T +61 2 9334 7700
1800 226 667
F +61 2 9334 7799
© Commonwealth of Australia 2011
This work is copyright. Apart from any use as permitted under the Copyright Act 1968, no part may be reproduced
by any process without prior written permission from the Commonwealth. Requests and inquiries concerning reproduction
and rights should be addressed to the Manager, Editorial Services, Australian Communications and Media Authority,
PO Box 13112 Law Courts, Melbourne Vic 8010.
Published by the Australian Communications and Media Authority
acma | 1
Contents (Continued)
Executive summary
Key findings
Accuracy and coverage of different methods of estimating antenna stock
Introduction and objectives
Background and introduction
Summary of objectives
Research methodology
Overview of the method
Scoping and development of discussion guides and questionnaires
Household survey—screening phase
In-home audits and auditor training
Technical assessment
Street-level observations
Industry research component
Data analysis and modelling
Household screening and in-home equipment audits
Descriptive statistics
Antenna equipment and condition
Location of antennas
Type of antennas and installation processes
Direction of the antenna
Number of television sets and their age
Perceptions of reception quality and surrounding landscape
Connections and wallplates
Variables that can be determined from street level auditing
Summary of technical assessments
Antenna coverage
Antenna age
Expert assessments of observed antenna condition
Technical antenna ratings by region
Mapping
Suitability of antenna systems for analog reception
Suitability of antenna systems for digital reception—households
receiving analog channels
Suitability of antenna systems for digital reception—those currently
receiving digital signals
Industry research
Antenna installers, suppliers and manufacturers
Television station personnel
Relative accuracy and coverage of alternative methods of
estimating antenna stock
Appendix A
Influence of factors other than antenna stock on digital signal strength
Appendix B
Recruitment Screener—community survey
Appendix C
In-home equipment audit—community survey
Appendix D
Industry questionnaire—television stations
Appendix E
Industry questionnaire—retailers/installers
acma | 1Executive summary
This report summarises the findings from a multi-phase investigation of household antenna stock in the Bathurst and Orange regions of NSW. The investigation included a comparison of research methodologies for estimating household antenna stock and an assessment of the suitability for each of those methods to be applied to other regions of Australia.
The project had two main objectives:
Provide valid and reliable estimates of household antenna stock in the coverage areas of Bathurst and Orange in NSW, and identify the possible implications for householders of digital switchover and channel restacking.
Develop alternative methods and tools to estimate household antenna stock that could be applied in other relevant regions in Australia.
The research methods used in the project were:
telephone screening and interviewing of 500 households in the region, including respondent-assessed or reported antenna type, age, condition and height, as well as the type and condition of antenna cabling and presence of masthead amplifiers (referred to as ‘householder responses’)
street-level observation of the antenna systems of the same 500 households, conducted by trained field staff (referred to as ‘street-level’ observations)
in-home audits of the television equipment, channel signal strength and reception quality of the same 500 households, conducted by trained field staff (referred to as ‘auditor observations’). These auditors also conducted more detailed observations of the antenna systems, walking around the outside of the home as necessary to make observations (referred to as ‘outside-home’ observations)
offsite assessment by technical experts of the signal strength measurements and antenna photographs taken by auditors (referred to as ‘technical assessment’)
industry interviews with antenna installers and suppliers in Bathurst and Orange, antenna manufacturers and importers, and field and operational personnel of the television stations operating in the area.
Key findings
Antenna type (bandwidth and polarisation)
All 500 households included in the study were selected on the basis of having one or more external antennas. Of the total, 33 per cent had two or more external antennas. Additionally, 20 per cent of householders also reported having a satellite dish (as well as other external antennas) and 18 per cent reported having an indoor antenna.
A total of 24 households (less than five per cent) did not have at least one external antenna. These households were therefore screened out and not included in the subsequent study.
Consistent with all digital signals from Mount Panorama being vertically polarised VHF, 74 per cent of all antennas directed at this transmission source (primarily Bathurst households) were found to have VHF capability and 94 per cent were vertically polarised. Table 1 shows that seventy-three per cent of antennas were vertically polarised VHF. The most common type was vertical VHF/UHF (39 per cent), followed by vertical VHF only (32 per cent). However, 22 per cent of antennas were vertical UHF only, four per cent were UHF only and one per cent had VHF but horizontal polarisation only.
For analog signals from Mount Panorama, antennas would be expected to be vertical and combination VHF/UHF. However, only 41 per cent of all antennas fell in this category, with the majority of others being vertical but VHF only (32 per cent) suited for ABC and Prime, or vertical and UHF only (22 per cent) as suited for the other channels.
Consistent with all digital signals from Mount Canobolas being horizontally polarised UHF, 82 per cent of antennas directed at this transmission source (primarily in Orange and surrounding areas) were UHF and 79 per cent were horizontally polarised. Seventy-eight per cent of antennas were horizontally polarised UHF. The most common type was vertical/horizontal VHF/UHF (45 per cent) followed by horizontal UHF only (27 per cent) and horizontal VHF/UHF (six per cent). However, 18 per cent of antennas were vertical VHF only.
For analog signals from Mount Canobolas, antennas would be expected to be vertical/horizontal VHF/UHF. However, only 45 per cent of all antennas fell in this category. Sixty-four per cent of antennas were vertically polarised VHF as suited for ABC and Prime, while 78 per cent of antennas were horizontal UHF as needed for the other channels.
Overall, 76 per cent of antennas were suited to digital reception of signals from Mount Canobolas or Mount Panorama, with 43 per cent of antennas having the bands and polarisation required for both analog and digital reception.
Table 1 Signal polarisation and bandwidth by signal sourcePolarity / Band/s / Mt Panorama % (n=183) / Mt Canobolas % (n=303)
Horizontal / UHF only / 4 / 27
Horizontal / VHF only / 0 / 1
Horizontal / VHF/UHF / 1 / 6
Vertical / UHF only / 22 / 2
Vertical / VHF only / 32 / 18
Vertical / VHF/UHF / 39 / 1
Vertical/horizontal / VHF/UHF / 2 / 45
Total / 100 / 100
Antenna condition, age and height
Table 2 shows the technical ratings of the main antenna condition (in bold). For comparison purposes, the table also includes ratings made by householders and auditing field staff. Technicians assessed 49 per cent of antennas as ‘good’, 46 per cent as ‘fair’ and three per cent as ‘poor’. Householders were more likely than either auditors or technicians to rate their antenna as ‘good’. Antennas in the minor towns were less likely to be assessed by technicians as ‘good’ compared to those in Bathurst and Orange.
Table 2 Antenna conditionBathurst %
(n=226) / Orange %
(n=233) / Others %
(n=41) / Total %
(N=500)
Good:
Technical assessment
Household response
Auditor view / 54
60
42 / 49
62
49 / 23
70
46 / 49
62
46
Fair:
Technical assessment
Household response
Auditor view / 43
27
51 / 46
27
43 / 68
13
49 / 46
26
47
Poor:
Technical assessment
Household response
Auditor view / 2
4
5 / 4
5
7 / 8
4
5 / 3
4
6
Don’t know:
Technical assessment
Household response
Auditor view / 1
9
1 / 2
6
1 / 0
13
0 / 1
8
1
Total / 100 / 100 / 100 / 100
According to technical estimates, the average age of all antennas was five years, with 91 per cent estimated to be no more than 10 years old. Antenna installers estimated that the average age was around 15 years while householders estimated the average age as 10 years. It should be borne in mind that estimating antenna age is difficult even for technical experts and results are provided for indicative purposes only.
Median height from the ground to the top of the antenna was estimated to be six to seven metres, with 93 per cent of masts being less than five metres from the ground to the top of the antenna. Further, 23 per cent of antennas had a masthead amplifier.
Digital television is not expected to require extensive upgrading of antennas
Based on the technical assessment undertaken by Australian Digital Testing (ADT), households within the region do not have widespread television reception difficulties with current digital television channels. In summary:
Seventy-seven per cent of all households have or are likely to have adequate reception of all five current digital television channels.
Only seven per cent of households were found to have inadequate reception. ‘Inadequate’ means no reception, partial reception (not all channels available) or poor reception with problems such as pixellation. (It should be noted, however, that signal strength can be influenced by a range of variables other than the antenna type, condition and orientation.)
A further 16 per cent were assessed as having or likely to have marginal reception (viewable but with some deterioration).
While relatively few external domestic antennas were rated as inadequate in Bathurst (six per cent) and Orange (five per cent), 21 per cent of the 41 antennas sampled in the three minor towns of Blayney, Molong and Millthorpe were rated as having inadequate reception, which is a significant variation despite the small sample size.
The main conclusion is that digitisation is not expected to require extensive upgrading of antennas, with the exception of the minor towns.
Picture and sound quality
Most of the households surveyed received good or excellent reception, although there were a few variations:
For analog reception, combined ‘excellent’ and ‘good’ auditor ratings were between 73 and 81 per cent for the picture quality for all channels, and between 74 and 83 per cent for audio quality.
Compared to analog reception, digital reception quality was significantly and consistently rated higher (91–95 per cent ‘excellent’ or ‘good’ for picture quality and 91–94 per cent ‘excellent’ or ‘good’ for sound quality).
Unlike analog reception, auditors rated digital sound and picture quality equivalently across all channels.
Only 1–2 per cent of the audits rated either digital picture or sound quality as ‘poor’ or ‘bad’, with minimal differences between the channels.
There were no significant variations in digital ratings between households receiving a signal from Mount Panorama or Mount Canobolas.
Antenna installers, suppliers and manufacturers
Eleven installers (including one who was also a major local supplier), one importer and one manufacturer were interviewed.
The average number of years that installers had been in the business was 28 years, with a range from five to 50, suggesting a mature industry.
Between them, the eleven installers fitted approximately 2,650 antennas a year, although the range was from 50 to 800 per year per installer, with two installers (one in Bathurst, one in Orange) accounting for more than half (1,400) between them a year. Those handling lesser numbers—such as general electricians and those installing other communication equipment like CB radios—tended to either be in semi-retirement or antenna installation formed only part of their work.
Installers reported that they select antennas based on what is suitable for the area, what is proven and reliable, and what is affordable for the customer. However, some installers recommend and install different types of antennas in the one area, based on what they have found to work in the past, which may or may not be the most appropriate method. In short, they appear to learn by trial and error and stick to what they know.
Accuracy and coverage of different methods of estimating antenna stock
Analysis of data was undertaken to contrast the various methodologies employed in the project, and to recommend an alternative to expert technical assessment for application to other areas when such assessment is not feasible. Of particular interest was how closely the results from street-level, outside home and household responses matched those from the expert assessment. In addition to the relative accuracy of the methods, the extent to which the antenna variables could be measured at all (that is, their coverage) was also considered.
The analysis found the following:
When ascertaining antenna bandwidth, the closest method to expert technical assessment was outside-home observation, with 71 per cent of antennas being classified as the same type. While outside-home observation was only slightly more accurate than street-level observation (68 per cent) and householder responses (65 per cent), 93 per cent of antennas could be classified using this method compared to 68 per cent for street-only observation and 61 per cent for householder responses.
When recording antenna polarisation (whether the antenna is positioned horizontally, vertically or both), street-level observations (69 per cent) were slightly more accurate than outside-home observations (64 per cent). However, street-level observations could only be made in 59 per cent of households, compared to 93 per cent for the outside-home method. Householder responses had noticeably lower accuracy (41 per cent) than the other methods and coverage of 61 per cent of sampled households.
All three alternative methods resulted in measures of antenna condition that were similar to those provided by the technical experts, with just over 50 per cent of observed conditions being the same as those made by experts. However, outside-home observations had the highest coverage (98 per cent), followed by householder response (90 per cent) and street-level observations (60 per cent).
Antenna age was difficult to assess even for experts. Householder responses and expert judgment resulted in the same age-range classification in only 34 per cent of cases. While the coverage of householder responses was fairly high at 87 per cent, a significant proportion of these are likely to have been very rough estimates.
From these results as a whole, taking into account both accuracy level and household coverage, the most effective method of predicting antenna suitability for digital reception when expert technical assessment is not feasible is outside-home observations.
Comprehensive street-level observations of the key antenna variables—the band/s the antenna was designed to receive, its polarisation, its condition and its height—could only be made in 54 percent of households. This raises questions about the viability of this method because it cannot be assumed that non-observable households are randomly missing from the sample of selected households.at random.
Householder responses produced a very high proportion of ‘don’t know’ answers, with complete estimates of the antenna variables obtained for less than 58 percent of interviewed households. Consequently, this method is also limited in its potential application. The equivalent figure for outside-home observations was 94 per cent.
If the outside-home observation method is to be used, it may not be necessary to pre-recruit respondents prior to visiting the household (as with the telephone survey). An auditing team would be able to identify households to visit using an agreed selection method, and visit each household to conduct a street-level observation. Where a street-level observation cannot be made because antenna and associated equipment are not visible, the auditor may attempt to contact the householder to gain permission to view the equipment from another vantage point surrounding (but within) the property. If the householder was unavailable, the auditor would leave a card requesting the householder make contact to arrange a suitable date to revisit. In the event that a householder refused, or if contact was not established through the card drop or by subsequent revisit, the household would be replaced with another sample point, sometimes being a neighbouring property.
Introduction and objectives
Background and introduction
This report summarises the findings from a multi-phase project conducted in April to June 2010, which sought to:
provide valid and reliable estimates of household antenna stock in the coverage areas of Bathurst and Orange in NSW, and the possible implications of channel restacking options
develop methods and tools that can be applied in other relevant regions in Australia.
The second objective required a comparison of methods, where results from various data collection methods were contrasted to identify the most effective and efficient way to estimate household antenna stock. Future studies will be able to apply the methods and tools generated in this study, providing a ‘best practice’ approach to obtaining estimates that are not only valid and reliable but are also cost-efficient.
Background to the study
The Australian Communications and Media Authority (the ACMA) is responsible for planning the use of radiofrequency spectrum for radio and television services. Planning since the mid-1990s has included the allocation of channels for digital television broadcasts for the switchover from analog to digital terrestrial television.