A Freeview box needs a fairly strong signal, from an aerial, before it can 'lock on' to digital transmissions.
If your portable TV was only using a built-in aerial, it will require another aerial to feed the Freeview box.
If you live close to a TV transmitter, you might be able to get a strong enough signal using an indoor aerial but, in most situations, a roof-top aerial is required. (The 'Total Control' product is just one of a number of aerials which claim that they can receive Freeview signals indoors. Like all such products, they only work in strong signal areas ).
Chris