HDHomeRun signal quality checks

hdhomerun_how_to_signal_check.md

Get the config tool

https://github.com/Silicondust/libhdhomerun

A good usage reference is available here:

https://www.silicondust.com/hdhomerun/hdhomerun_development.pdf

To scan all channels

./hdhomerun_config <id> scan /tuner<#> [filename]

To get a specific channel

Set the channel

  ./hdhomerun_config <id> set /tuner<#>/channel auto:<channel number>

  ./hdhomerun_config <id> get /tuner<#>/status

quick signal check reference

Example output: ch=qam:33 lock=qam256 ss=83 snq=90 seq=100 bps=38807712 pps=0

• ch = channel requested
• lock = actual modulation detected
• ss = signal strength. 80% is approximately -12dBmV.
• snq = signal to noise quality (based on analog signal to noise ratio).
• seq = symbol error quality (number of uncorrectable digital errors detected).
• bps = raw channel bits per second.
• pps = packets per second sent through the network.

A note from HDHomeRun REF

There are three percentages reported by the HDHomeRun -

Signal Strength (ss)

• raw power level as measured by the receiver

Signal Quality (snq)

• how clearly defined the digital data is

Symbol Quality (seq)

• Amount of correct or corrected data over the last second

The above definitions can be confusing, so a much simpler definition is to imagine listening to the radio:

• Signal Strength represents the volume
• Signal Quality represents how clearly you can hear the lyrics
• Symbol Quality indicates the percentage of the lyrics you could hear or guess correctly

As it turns out, Signal Strength is somewhat irrelevant; if your antenna isn't pointed properly, it doesn't matter how loud you turn up the volume, the static will prevent you from hearing the lyrics correctly. Similarly, amplifying a weak HDTV signal can result in a high signal strength but too much noise to decode the digital data correctly.

Use the Signal Strength for a rough idea of direction, but align the antenna for the highest Signal Quality, ignoring Signal Strength. When aimed correctly, Symbol Quality will show 100%, indicating no errors in the output. Splitters and amplifiers can introduce noise which will lower the Signal Quality, even if the Signal Strength increases.