Does this sound right or should I be getting better strengths?
If you mean with your current aerial, aerial location, installation, cabling, connectors, attenuators, amplifiers and HDR-FOX T2 should you expect different strength, then all those things will influence the signal metre. Vary those and it could be a lot lower or it could be higher.
You will not be able to get better than 100% quality. What are you attempting to achieve by your question?
If you increase the signal strength by too much the quality still won't be better than 100% and with too much signal you could face a noticeable drop in quality and some channels could become unwatchable.
Regarding the difference in strength there are a few reasons but you would need to obtain for yourself additional information concerning your metre readings and then armed with that look at what Winter Hill is broadcasting and look for a pattern, e.g. find out which 2 muxes are giving the 30% strength and which 6 are giving the 50% strength and see if with that information you can see if it is accountable by what Winter hill is broadcasting, plus see if it really is Winter Hill that you are receiving from. That why you can start to identify if it is a possibility that the 2 muxes are weaker because they are out of range of your aerial's frequency group, or because the broadcast power is lower for some frequencies, or something is up with the aerial or the state of its cabling. If you can't physically examine the entire length of the cable itself take into account what 20 years could do to a cable that hasn't been attached too well as that can (apparently!) introduce loss at selective frequencies.
Also consider what you already know about the aerial especially its likely channel range. Also look at the aerial and try to narrow down what type it is and whether all elements are still in place.
If you are still wondering about the level of signal strength despite being 100% quality then like what prpr said you should look into how the aerial and how the aerial is connected to the HDR-FOX T2. Find out if it is just a cable or if there is anything else the signal is going through on its way from the aerial to your Humax. One example is an attenuator because at one time it was getting so much signal it was damaging the quality. Depending on the aerial some times they don't really need that accurate alignment. Find out where and how the aerial is mounted, (horizontal or vertical or not really either), and if it too has line of site or is hampered by being in the loft with roof materials that are helping to shield reception of RF signals. Also check the state of the aerial and cable as well as anything else involved.
... 30% strength on a couple of others.
Does this sound right or should I be getting better strengths?
A "couple" may be appropriate or it could indicate an issue, or an issue heading your way for 2020.
If one of them is ARQ B and then you'll probably need to adjust your installation by 2020. As your aerial is 20 years old it was porbably fitted to receive the frequencies of Winter Hill as they were back then. If its 30% for ARQ B now, then it is probably going to be lower than 30% for the next Winter Hill muxes that are going to be moved even further away from the old Winter Hill frequencies in the first half of 2020.
