NEWS AND NOTES

Ellesmere Guardian, Volume XLVI, Issue 3257, 25 September 1928, Page 6

NEWS AND NOTES

Gold crayon rubbed into the engravings of your panel gives an excellent finish. Enough should be rubbed into the scratch to make a clear marking, the remainder being rubbed off Carefully. » * # When connecting your loud speaker to the set, be sure (unless a filter circuit is used) that its red terminal is joined on to the terminal on the set, which is connected to H.T. positive. If this is not done, there is -risk of serious damage to the loud speaker. # * * If two condensers of equal value are connected in series, the total value of the arrangement will be. half that of one of the condensers. "When two condensers of equal value are connected in parallel, the total capacty of the arrangement will be twice that *bf either of the condensers. • • « It pays to test the voltage of the grid bias battery occasionally, as insufficient grid bias means a heavier than necessary drain upon the B battery. . * • • ' - A broadcast receiver cannot be used for short-wave reception unless a special adapter is used. This adapter is plugged into the detector socket of the set, thus using audio stages only. If the receiver has one or more radio frequency stages, these valves mus,t be removed, » * * * Those who have thought of buying a short-wave receiving set need not worry about the length of their aerials. The aerial used for receiving the ordinary broadcast transmission serves admirably for short-wave reception, without any shortening or other alteration. • # « • I For a small soldering job such as joining two twisted wires together,- it is advisable to heat the joint well first, as the solder will then run through the joint and make a solid connexion. * » » Very short waves —i.e., those below about 50 metres—do not travel along the surface of the earth, but are projected into space and reflected by the heaviside layer. For this reason, the signals from short-wave stations may not be so strong near to the point of origin as they are at a distance of several hundreds, or even thousands, of | miles away. It is surprising, when one looks around, to see the number of broadcast listeners who employ the careless j method of leading the aerial through the wall ventilator, or, worse still, under the window sash. If one only thinks for a moment, one must realise that the principle is wrong. It might do very well in the very dry weather, but what about the wet and damp weather? Some text-books tell us that fully 25 per cent, losses occur through j 'carelessly installed lead-in devices. j

The importance of having an aerial of thick or stranded wire is generally realised, but it must be remembered that it is just as necessary—in fact, more so—to use low-loss wire. for down-leads and earth wires. • # # If transformers of too high ratio are used, distortion will result.. If possible, transformers of the' same make should always be used when building a set, as some manufacturers wind these instruments in different directions, thus causing oscillation as soon as the audio stages are turned on by means of the rheostat. The remedy for this is to reverse the leads on one of the transformers, taking the plate lead to B plus, and vice versa.