Network Scan - Humax bug or SC mis-configured?


Just retuned the HDR but instead of doing an automatic scan which takes ages I thought I would clear the channel list (i.e. start a scan and then abort) and then perform a manual scan with network search enabled.

From Sutton Coldfield there are 8 muxes and the frequencies are:

SD - 39, 42, 43, 45, 46, 51 (Local TV)
HD - 40, 33 (COM7)

I noticed that when I selected the SD mux on 42 it correctly tuned in all 6 SD muxes but not the 2 HD ones.

I cleared the list again and selected the HD mux on 40 - this time it tuned in the HD mux on 40 and all 6 SD muxes (but missed the HD mux on 33).

I cleared the list again and selected the HD mux on 33 - this time it tuned in the HD mux on 33 and all 6 SD muxes (but missed the HD mux on 40).

At this point I went back in and manually tuned in the missing mux on 40 (switching network search off) I ended up with all 8 muxes but there is obviously either a misconfiguration at the TX or there is a bug in the Humax software when performing a Network search.

I have a non PVR HD model as well. If I get chance I will re-tune that later and see if that exhibits any of the above problems.

HDR S/W version 1.03.06 with CF 2.21.

Update: Just re-tuned the HD, it did exactly the same so obviously if it is a bug then it exists on both HDR and HD variants (HD S/W version 1.02.29 - No CF).
I can't say I have ever seen any documentation that explains what a Manual search with network Search = Yes does, however I guess it retrieves the Network ID from the selected UHF MUX channel (West Midlands 12325 for Sutton Coldfield) and then stores any other MUXs it finds with the same network ID. As all 8 MUXs you have detailed do have the same ID, it does look as if the Humax is doing something strange, it wouldn't surprise me if you had to manually select one SD MUX and one HD MUX but it's hard to explain your findings
It does not scan the entire UHF band looking for muxes with the same network ID. I believe each mux carries extra data which holds the frequencies of all other muxes broadcasting from that TX and it uses this information to tune to each of those specified muxes in turn. Obviously something is wrong as it is not working correctly. As it only has to tune in 7 more muxes (when it works correctly) and it knows the frequencies to tune to then it saves a significant amount of time compared with an automatic scan (several minutes in fact).
I have always recommended leaving this setting off because of the strange results it produces. Just run manual.
I normally do just use manual but I thought I would experiment! I read somewhere a few weeks ago what Network Scan did (can't find the article at the moment) so I thought I would give it ago.

Incidentally, since moving to 1.03.06 auto scan actually appears to work. I am in an area where I can pick up all multiplexes from Sutton Coldfield and Brierley Hill and selected multiplexes (at lower strength/quality) from two other transmitters. This used to cause chaos on pre 1.02.28 firmware as it would just store the first occurrence of that multiplex and shunt the repeats up into the 800's so you would end up with multiplexes tuned from 4 transmitters.

On 1.02.28 firmware it would ignore the two out of area transmitters but would still tune in both SC and BH. The region selection option would then only show West Midlands and selecting this would then give a mixture of multiplexes from SC and BH tuned in at the correct LCN's (none in the 800's). Not what you want for reliable recording. Incidentally we have 1.02.29 on the HD and it also does this so I normally tune it manually (can't access the rear very easily to remove/re-insert the aerial during an auto-scan).

Since moving to 1.03.06 it now also ignores the BH multiplexes and stores SC only so I no longer have to manually tune or remove and re-insert the aerial at the relevant points as it auto scans.
Yes I had my wrist slapped by Black Hole when I reoported this in December I.e. we don't recommend it. Clearly its either a mistake that the Free View providers are doing or its a facility that isn't in the Free View spec so there is no requirement to implement it.

The concept is similar to the satelitte one where you just bring in the channels associated with a provider. So the network search should be relative to the site, it always has been. May be because HD channels are not always provided at an SD site the powers that be have dropped from being implemented.