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Power usage for Sky digiboxes
Overview
This page documents various measurements I've made on the power used by
various sky digiboxes in various states.
Test environment
To try and keep comparisons fair, the sky boxes were configured as follows:
- RF2 power on
- 1 satellite cable (even on sky+)
- Tuned to BBC1 Scotland
- No viewing card (unless otherwise stated)
- RF channel 68
- Single output connected: a scart -> svideo cable in tv scart socket
Results
| Digibox | Model | Version | Serial | OS | EPG | Power usage |
|---|---|---|---|---|---|---|
| Panasonic TU-DSB31 | 2.1.U | 0F0302 | 0029318917 | 1.2S4FI | 3.6.4.18 |
on: 0.12 A
off: 0.11 A |
| Grundig GDS3000 | 2.81 | 4E0503 | 0034923662 | 1.2S4FH | 3.5.3 | on: 0.10 A
off: 0.09 A |
| Pace BSKYB 2500S5 | 1.2.42 | 9F0702 | 0037670161 | 1.2S4FJ | 3.7.6 | on: 0.07 A
on: 0.08 A (with viewing card) off: 0.07 A (with & without viewing card) |
| Thomson sky+ DSI 8210CS | 127k148 | 4E2104 | 0147262869 | 1.31B03 | 5.02.f | on: 0.16 A
off: 0.15 A (harddisc still running) off: 0.09 A (harddisc spun down) |
| Pace sky+ BSKYB 3100(1) | 6.001 | 9F2101 | 0070297771 | 1.31B06 | 5.04.d | on: 0.15 AMP
on: 0.16 AMP (with viewing card) off: 0.14 AMP (harddisc still running) harddisc would not spin down |
The figures are unfortunately a little imprecise due to the equipment used to do the monitoring.
(1) non-standard harddisc fitted: maxtor diamondmax plus9 160GB
Conclusions
For the standard digiboxes, the saving from going into standy is fairly low, saving less than 10% of the usage. In fact, the variance between the Pace (which was the newest of the boxes under test) and the other models shows that the design or components are a big factor.
The small saving is not entirely unexpected, it is well down that the digibox continues to decode data from the satellite in standby. There are at least three reasons for this:
- Receiving activation / deactivation messages for the viewing card
- Receiving over the air firmware updates
- Keeping the EPG up to date
In addition, the digibox continues to supply power to both the LNB and the RF2 output (the latter so the box can be powered on from a remote tvlink).
It's unfortunate that the Pace Sky+ box would not spin down it's hard disc. This may have been due to the non-standard harddisc, however I believe at least one of the previous firmware versions did spindown the disc. The saving for the sky+ does appear to be more significant, reducing power usage by 43% in the case of the Thomson.
Joseph Heenan, joseph@dusky-control.com