Answering my own questions in case anyone else is wondering (using a Triax TSS400 on the latest firmware) - some things mentioned have only just been sorted in TVHeadend so make sure you are running 3.9.1285~g1579757 or later.
> 1. When used with TVHeadend* it appears that each tuner has a 1:1 relationship with TVHeadend. Assuming this is correct if I got a future TV which supported SAT>IP could that use one of the tuners with TV Headend using the other 3 or does TVHeadend need exclusive access to all the tuners?
They do indeed have a 1:1 relationship. I've been able to use apps on a specific tuner. I guess the exact question when it comes to TV's depends on how they implement it.
> 2. Can it be used with less than 4 LNB inputs? The Triax specs mention single and dual LNB inputs so those are possibilities, but what about 3?
> 3. What about LNB 1,2,and 3 being connected to 28.2'E and LNB 4 connected to 19.2'E (on my dish plonked in the garden on F1 race weekends)?
Yes - I've got two cables connected to 3 inputs (one directly, and the other is split to the other two via a splitter) and this works well (TVHeadend has a concept of slave tuners so when two are sharing the same cable they can both tune to different frequencies in the same band - e.g. Low Band Vertical). LNB 4 is connected to my 19.2'E dish on race weekends and works well.
> 4. If I've done my maths correctly my HomePlugs should be able to support two multiplexes in full (44Mbps according to Flysat, my homeplugs themselves sync at 185Mbps but are limited to their 10/100 Ethernet ports! - When copying files windows shows 11.3MB/S which is just shy of the 12.5MB/S theoretical maximum) so I should be okay streaming up six (SD)*** channels over them shouldn't I?
I've managed to watch and record a combination of SD and HD channels (including recording all six BBC Commonwealth Games SD streams while watching STV HD) and this handles well. I do know my HomePlugs show very good connections between one another though so YMMV.
> 5. Can the tuners control a DiSEqC switch should I use one later (e.g. Astra 19.2, 23.2, and 28.2E + Hotbird)?
The UI on the Triax does indeed mention DiSEqC (but I've not needed to use it), The LNB options in the UI are as follows:-
LNB Type: Unicable Quattro Quad/DiSEqC
Presumably Unicable just needs a single cable connected to port 1 and does the Unicable stuff
Quattro would do the Low/V, Low/H, Hi/V, Hi/H on the ports as marked and internally switch the signal
Quad/DiSEqC would do the normal switching (and is the mode I use).
> #* When recording more than six channels my media centre PC runs out of steam anyway - HDD, USB, or Processing power could be to blame - unless deliberately testing stuff to the limit the most I've ever had is five TV channels + one radio station so this isn't too limiting.
My Revo has been a lot happier recording stuff on the SAT>IP tuner, not had a single drop out (except during heavy rain) when those were frequent on my USB DVB-S tuner. The channel changing has also been noticeably faster. I've been able to record six SD channels and watch a HD channel too. Something I couldn't from my USB tuners.
Now to find a DVB-T2 SAT>IP Tuner :p
