The latest firmware versions (from 01.05.334 & 01.07.055) are intended to handle duplicate channels correctly as per The Free TV Australia Operational Practice OP-41 Logical Channel Descriptor. However, in some locations it selects the lower quality channels to use. In this case, clearing all services and using the appropriate partial scans (as in Dealing with duplicate services/Avoiding duplicates below) will force the use of the correct transmitter sites.
Scanning for Services
How do I know whether I have duplicate services
What problems do duplicate services cause?
Sounds a bit of a mess. Can't it be made easier?
Dealing with duplicate services
Removing duplicates
Avoiding duplicates
A worked example
Removing duplicates
Avoiding duplicates
How do I find out what transmitters I can receive from?
Scanning for Services
Normally, scanning for services on the Beyonwiz is simple. Just go to Setup > Config. > Service Scan; Scanning Range = FULL, and then Start Scanning.
However, a full scan is slow, and can be made faster in some cases by using Scanning Range = PARTIAL.
In other cases, you may be receiving the same digital TV services from different transmitters on different channels (I use "service" and "channel" here as described in peteru's note in the Reception FAQ). If you do a full scan and have duplicate service definitions, this can cause a number of problems with setting timers and other functions on the Beyonwiz.
A "service" as peteru describes it, has a Logical Channel Number (LCN), which is its identity in the Digital TV system. These numbers are different from the channel number, which identifies which part of the radio spectrum that a broadcast is made on. The same broadcaster (e.g. ABC) broadcasts on many different channels, depending on the transmitter. However, LCN 2 is always the digital service ABC1.
The aim of the FAQ is to describe what you need to do to avoid duplicate services, and to remove them if you have them. It will also, along the way, show how you can, in many circumstances, speed up a service scan by using a partial scan, and also point you to some resources for finding out what channels you are receiving from.
How do I know whether I have duplicate services
"Duplicate services" here doesn't mean seeing the same content on two different services (or LCNs). For example, ABC1 is normally transmitted on both LCN 2 and LCN 21.
By "duplicated services", I mean that your All Services list (press LIST in live TV and then BLUE for All Services), that there are two entries for ABC1 on LCN 2, on different channels (and different frequencies).
The Services list is a scrollable list that shows each scanned LCN and the service name it represents. At the bottom left of the services list, the broadcast channel number and the frequency of the channel carrying the service. A broadcast channel carries a number of services, both video and radio (audio only). At the moment only SBS and ABC channels carry radio services.
Duplicate services are services where the same LCN is repeated and associated with more than one different broadcast channel number. The service name can be repeated without the service being a duplicate service. For example, ABC1 is associated with LCN 2 and LCN 21. That is normal, and is not considered a duplicate service. ABC1 appearing twice on LCN 2 is a duplicate service.
What problems do duplicate services cause?
So, why should I care about duplicate services? After all, I can just set up one set in the Favorites and only use them, as I do with, say the ABC1 on LCN 2 and LCN 21.
Duplicate services (duplicate LCNs) can cause a variety of problems on the Beyonwiz. These include:
- The Beyonwiz selecting the weaker of the two channels to use, giving poor reception when the signal from the stronger transmitter is very good.
- Failure of the EPG to display correctly, with services visible in live TV missing EPG information. This can affect both Free-to-Air EPG and IceTV Guide.
- Timers failing to record correctly.
- When changing channels while dual recording, the tuner selection algorithm can be confused by the duplicate channels and may alter the tuner of one of the recordings mid-stream, causing recordings to cut short and/or get parts of a different service in them.
The Free TV Australia Operational Practice OP-41 Logical Channel Descriptor sets out quite clearly what a digital TV receiver should do if it receives duplicate services on more than one broadcast channel:
Unfortunately, Beyonwiz PVRs don't implement this strategy, so you need to perform this process manually.3.2.3 Signal Quality Matrix
If competing duplicate services (i.e. those that have the same LCN allocated) are received from different transmitters, then a receiver that complies with the Australian DVB-T receiver standard, AS 4933 [5], will place the service with the highest received quality in the correct LCN position and the other(s) made available to the user, for example stored at the next available unallocated number in the range 350 - 399, unless it is intentionally duplicated by the broadcaster as indicated by its presence in the frequency list descriptor of the NIT (see section 3.2.2), in which case it can be safely discarded.
UPDATE (Sep 2010):
The latest firmware versions (from 01.05.334 & 01.07.055) are intended to handle duplicate channels correctly as per The Free TV Australia Operational Practice OP-41 Logical Channel Descriptor. However, in some locations it selects the lower quality channels to use. In this case, clearing all services and using the appropriate partial scans (as in Dealing with duplicate services/Avoiding duplicates below) will force the use of the correct transmitter sites.
Dealing with duplicate services
There are two ways of managing duplicate services, either do a full scan and then remove all the duplicated services, or, clear all the services, and then use a partial scan (or a number of partial scans) you ensure that you only scan one channel for each broadcaster.
Removing duplicates
- Make a note of your Favorite services lists and all your timers, especially if you use manual timers.
- Use LIST, BLUE All Services to see all services in the service list menu.
- Find all the duplicate service LCNs, and note down the broadcast channels that the services are associated with. For each duplicated LCN, you'll find a different broadcast channel number.
- Pick one representative service from each broadcast channel that's causing duplicate LCNs and change to the service in the Services LIST. Then use POPUP>Tuner Information and make a note of the Signal Strength and Signal Quality for each broadcast channel causing duplicated services.
- Choose the channel you want to keep from each set of duplicates. This will usually be the one with the best Signal Strength/Signal Quality, but if two channels have similar signal strength and quality, then simply choose the one you prefer (e.g. possibly a metropolitan and regional transmitter for the same network; Seven vs Prime, for example).
- Delete all the services associated with the channels you don't want to keep (YELLOW Delete button in LIST). Use the Radio/TV button to check radio services as well as TV services. Duplicated radio services need to be deleted, too.
- Check the service list for duplicates or other errors (have you deleted more services than you intended). If you've deleted too many services, you may want to do the rescan method suggested in the next section.
- Re-create any lost timers. If you use IceTV, go to My Account>Interactive in your IceTV account Web page and Resend All Timers for the device. Fix your Favorites lists.
- Re-select your Favorites list.
Avoiding duplicates
This method can also be useful for speeding up scans even if you don't have problems with duplicates. For example, the Black Mountain transmitters in the ACT transmits digital TV on channels 6 (SC Ten), 9A (ABC), 11 (WIN), 12 (Prime), and 30 (SBS). By doing a PARTIAL scan from channel 6 to channel 30 (the range is inclusive, so channels 6 and 30 will both be scanned), you can speed up your scan considerably, by scanning only 13 channels out of 52. This is possible to do in many locations, but the channels and scan ranges will be different.
- Make a note of all your timers, especially if you use manual timers.
- Use LIST, BLUE All Services to see all services in the service list menu.
- Find all the duplicate service LCNs, and note down the broadcast channels that the services are associated with. For each duplicated LCN, you'll find a different broadcast channel number.
- Pick one representative service from each broadcast channel that's causing duplicate LCNs and change to the service in the Services LIST. Then use POPUP>Tuner Information and make a note of the Signal Strength and Signal Quality for each broadcast channel causing duplicated services.
- Choose the channel you want to keep from each set of duplicates. This will usually be the one with the best Signal Strength/Signal Quality, but if two channels have similar signal strength and quaility, then simply choose the one you prefer (e.g. possibly a metropolitan and regional transmiter for the same network; Seven vs Prime, for example).
- Work out a channel range, or small set of channel ranges that will include all the channels you want to keep, and not include the channels you don't want to keep.
- In SETUP>System>Initialize, Clear Service Information.
- In SETUP>Config>Service Scan, use Scanning Rnge: PARTIAL and set Start Channel and End Channel to the first and last channels of one of (or the only) the ranges of channels you want to include. Repeat this step for other ranges if you need to.
- Check the service list to ensure you have the service coverage you want with no duplicates.
- Re-create any lost timers. If you use IceTV, go to My Account>Interactive in your IceTV account Web page and Resend All Timers for the device. Fix your Favorites lists.
- Re-select your Favorites list.
A worked example
In Adelaide, there are three digital TV transmitter sites.
The channels you want are:
- Mt Lofty transmitters (most of Adelaide): 6, 8, 11, 12, 33
- Grenfell Centre (city) transmitters (Adelaide Foothills): 54, 57, 61, 64, 66
- Kettering Rd transmitters (Elizabeth South), ABC and SBS only: 61 & 64
They will get services from channels 6 (Seven), 8 (WIN), 11 (Ten), 12 (ABC), 33 (SBS), 61 (SBS) and 64 (ABC). This means that all the ABC and SBS services will be duplicated, but not the commercial services.
Removing duplicates
To remove duplicates in this case, check the Signal Strength/Quality for one service associated with each of channels 12, 33, 61 and 64. If the best signal scores are for ABC on 12 and SBS on 33, delete all services associated with channels 61 and 64. Don't forget the radio services! If the best signal scores are for ABC on 64 and SBS on 61, delete the services associated with channels 12 and 33.
Avoiding duplicates
Check the signal scores for one service associated with each of channels 12, 33, 61 and 64 as for Removing Duplicates and decide which channels you get the best ABC and SBS reception from.
In SETUP>System>Initialize, Clear Service Information.
If you want to receive ABC and SBS from Mt Lofty (channels 12 & 33), simply do a PARTIAL scan from Start Channel 6 to End Channel 33. This avoids scanning the Kettering Rd channels 61 and 64.
If you want to receive ABC and SBS from Kettering Rd, and the remaining channels from Mt Lofty, it's a bit more complicated. You need to do partial scans from channels 6 to 11, and then from 61 to 64, to avoid scanning channels 12 and 33, but including all the channels you want.
How do I find out what transmitters I can receive from?
The ABC's Tuning In Web page lets you look up the reception coverage of their transmitters. Just enter your suburb name or postcode to get a list of the ABC transmitters that might cover your location, and click on each of the ABC Digital links to see the coverage. Clicking on the coverage map will give you a larger view of the map. This will give you a hint to the coverage of the other broadcasters at the same site, but because of possible differences in the transmitter mast locations and the transmitter power, the ABC maps will potentially be less accurate for the other broadcasters. Unfortunately, as far as I know the ABC is the only broadcaster to provide this useful service.
The Australian Communications and Media Authority (ACMA) produces the Radio and Television Broadcasting Stations book. This is an authoritative listing of all licensed radio and television stations in Australia. Two of the most useful chapters are 8. Television by Channel Order and 9. Television by Area Served. The first is useful to help find where the transmitter is for a particular broadcast channel you are receiving, and the second can help find what transmitters are in your area. Digital TV transmitters are highlighted in light purple. The Contents and Explanatory notes helps interpret the data, and the General Information section has some information about channel frequencies and an outline of some of the broadcast standards.
Unfortunately, although chapter 9 lists the location of all transmitters' by latitude and longitude, that's a bit cumbersome if you want to find the nearest transmitters. The named area served can be useful, but the naming isn't always obvious.
The same Web page on the ACMA site also has a the transmitter data (more than what's in the book form) available as a Microsoft Excel spreadsheet (also readable using OpenOffice Calc) and a Microsoft Access database. Both of these forms are useful if you want to process the transmitter location data.
For the ACMA spreadsheet, there's a commandline tool, rtv2kml, that allows you convert CSV files written from the spreadsheet into Google Earth KML placemark files, so you can display the transmitter locations in Google Earth. When you click on the transmitter icons in Google Earth, you get a popup containing the basic information about the transmitter site and the transmitters there. rtv2kml runs on Windows, Linux, OS X and Cygwin. There are "pre-compiled" versions available for Windows, OS X and Cygwin. If you don't use the pre-compiled version, you need perl installed on your system. There are detailed installation notes in the README.txt in the distribution.
The Google Earth placemarks let you see at a glance where nearby transmitters are, what stations broadcast from the transmitter sites, and their frequencies, power, polarisation and whether the transmissions are directional. Unfortunately, there's no information about the main transmission directions for directional broadcasts. You can get some idea of the directions from the ABC coverage Web site mentioned above.
Thanks to tonymy01 for help with the section on problems caused by duplicate services and to sub3r for drawing my attention to the fact that the automatic handling of duplicate services doesn't always work.
Last update: 15 Oct 2014. Updated ACMA Radio and Television Broadcast Stations book link.