Need help with new cable tuner - signal poor

[adm]

yes - a mix of male and female coax/f adaptors to terminate the cables appropriately.

think you are right about the signal strength - been a learning experience

I've reverted back to a single cable connected to the main feed and the 2nd loop through - that way atleast I get perfect reception on one tuner until I get a suitable amplifier - maybe for the 2nd feed

As I've posted before, 1 input and 2 outputs and fit the amp/booster after the passive splitter and then a lead from each of the amp/booster outputs to each of the tuner inputs. This way you can isolate each tuner.

Consider:
i) Both tuners are exactly the same and if one is marginal on signal strength the other will also be marginal, hence both need an increase in signal level
ii) If tuner 1 output is causing problem with noise all you will be doing by placing an amp between tuner 1 and tuner 2 is an amplification of the noise.

- any thoughts on something like this? - http://www.ebay.co.uk/itm/Mix-Digita...MAAOSwi0RXyEGm

In my opinion amplifying frequencies up to 2400 MHz may just introduce more noise into the system. An Amp/booster up to 1000Mhz (UHF) is more suited for amplifying terrestrial/cable signals.
Note: I'm not sure of the highest frequency used by Virgin but be aware that for terrestrial TV via an aerial the frequency range has been reduced to 700MHz and some of the UHF amp/boosters now incorporate a 4G (mobile phone) filter to exclude frequencies above 700MHz.

The gain of the amp you link to is 20db which will amplify your signal level by x10. I suspect that a gain of x1.5 (4dB) to x2 (6dB) is more than adequate as you say that your system appears to be is just on the point of being unreliable. A 20dB (x10) gain is likely to completely overload (in a non destructive way) the front end of your tuners and you will end up with no channels being detected.

Have you got the 5V output turned on? menu -> set-up -> sevice searching -> tuner configuration -> select each of you cable tuners and check for 'Enable 5V for active antenna' = off. If this is currently switched to on it may be the source of your problem.