Our loft conversion is almost complete but we have discovered the builder has left our TV aerial amp/booster under the floor boards in the insulation. We are having a new TV aerial fiited and the guy will need access to the booster box to change the wiring. The builder said they will just get some type of electrical join and move the booster out as they ae not sure it will reach far enough to fit on a wall. Is this possible? I'm worried they will educe our signal or make a mess of it etc
The walls have all been skimmed now and we have 2 TV points downstairs that need to be connected.
Builders and sparks shouldn't be let loose on anything to do with TV aerials. If they don't bugger it up by wiring the stuff wrong e.g. daisy-chaining aerial points like they're wiring electrical sockets, Oh FFS
, then they'll botch it with the cheapest coax, half-arsed plug fitting, and bending the coax in ways that gives me nightmares.
If your TV aerial guy is any good then for a start he'll be using all-copper coax (e.g. Webro WF100, Triax TX100, Labgear PF100) which loses just 1.5dB per 10m (approx). It's very unlikely you'll need runs of 10m, so your system losses will be less. Also, they should be using compression plugs for any connections where they're going to end up concealed from sight. There are a couple of reasons for this.
First, the way the plug attaches to the cable provides a tremendous amount of grip for a minimal amount of cable compression; far more than you'd get with screw-on type plugs and a much kinder bond than with crimp. You'll need around 40lb of pull force to remove a properly fitted compression plug. Incidentally, this is based on good coax with a quality outer sheath. Cheaper RG6, the stuff with a copper coated steel core, is often found to have a loose fitting outer sheath that's prone to stretching. The result is a bit like a tortoise pulling its head back in to its shell. The centre core of the coax can come out of the plug end and break the electrical contact. That's not good at any time, but when the joint is hidden from sight...
The other reason is that the compression plugs often include a moisture seal gasket. It's a minor point - particularly for all-copper cable which is very tolerant of moisture (steel core/aluminium braid cable isn't) but it provides a little more friction to keep the joint secure.
The joint will be formed by two compression F-type plugs fitting to an F-type threaded barrel back-to-back connector. If you wanted to go belt-n-braces then an outer layer of clear heat-shrink tubing would finish the job, but I only do that on rare occasions.
The total system gains and losses can be both predicted and measured. The nett effect can then be compensated for if required. Passive joints like this won't change the signal Quality measure. They'll only impact on the strength and that's no so critical. As long as your TVs get a minimum of 50dB signal strength for the weakest mux(es) then they'll be very happy. Your aerial guy should know when he's on-site what he needs to do with the aerial choice and any signal management to hit this target.
