A Corner for Beginners

Radio Record, Volume II, Issue 29, 1 February 1929, Page 11

A Corner for Beginners

By

Observer

A Washing Copper as Earth. Somp time ago you were good enough to advise me in regard to the use of an old copper as an earth, at the same time expressing a wish to know the result. I am now able to advise you that it is a complete success and I am

Pm reueee Tis eee ieeae foe to Tho) getting wonderful results. The volume has greatly increased and the tone is much clearer, I can now hear every word of a speaker quite distinctly 7ft. away from the small loudspeaker operating direct off the erystal without any amplification. I have had four headphones and a bar amplifier working the one loudspeaker simultaneously, and the speaker volume appeared little less than when working alone off the set when earthed to the water pipe. TR

A few particulars of the installation may be of interest to you. The aerial is a single 1/14 wire 186ft. effective length, about 16ft. above the instrument where it is fixed to the house and about 2 to 8ft. higher, where it is carried by a tall’ gum tree. To get over the difficulty of sudden gusts of wind snap-

ping the aerial-which happened twice -I have fitted strong springs at each end, as well as a counter-weight at the tree, and now find that there is no whipping of the aerial. I should have mentioned that the ground falls rapidly towards the tree which is about 5Oft. high to the aerial pulley. My leadin is 7/20 soldered in a special copper clip which I made 0 serve as a connection between the 1/14, 7/20, and lightning arrester. My earth wire is about 11ft. long from instrument to old copper, and is 7/16 cable. The detector is a permanent crystal, When cutting holes:in the old copper I cut three rows staggered around it, each containing seven V cuts about 14in. on the side. The top and bottom rows are bent out at right angles and the centre row bent in. The copper is filled with coke layers and fine earth alternately and a space of about 4 to 6in, around the outside is similarly treated. The amount of water absorbed by this filling surprised me. As wireless is ho longer a luxury, in. my opinion, I have wired an outlet to every bedroom, the breakfast room and living room, and a set of ’phones hangs at the head of each bed, so my household makes good use of 2YA and gets a good 30s. worth. Thanking you for | }

your advice-JOHN T. MUIR (Khandallah). Mr. Muir’s Earth. R. MUIR’S earth was described in our special issue of December 14, The salient points in the installation are as follow :- An old washing copper was taken and perforated with holes as described in the recent letter above. To the copper was soldered seven strands of 7/18 cable. This was sunk several feet in the ground, the copper being first filled with clinkers, and kept upright in the ground. Leading to this is a down pipe by which the copper and its contents ean be continually moist. The earth has no doubt proved very effective ,and as in certain places in Khandallah it is particularly difficult to get a good earth, this system shoud prove admirable for anyone who has such a difficulty, and should be worth while installing by those who have facilities to do so.

Important Notice Regarding Enquiries S our service is now being fully availed of and as almost every mail brings in a large number of enquiries on various topics, it has become necessary to adopt some system of uniformity. Correspondents are therefore requested to observe carefully the following points. Failure to observe these may mean delay in answering and even the loss of the letter. 1. Addresses.-All technical correspondence, whether inviting reply or not, must, in future, be addressed: "The Technical Editor," ""N.Z, Radio Record," Box 1032, Wellington. This includes letters to "Pentode," "Galena," and "Observer," as well as those that have in the past been erroneously addressed the Editor. 2. Each letter to bear (inside) the department to which it re-fers:-Construction, Crystal Corner, Questions and Answers, or General. 3. Letters inviting reply must be accompanied by a stamped and addressed envelope, but the right to answer any letter through the columns is reserved. Correspondents should watch the columns carefully as one letter may be answered in more than one section. 4. Advice requiring discrimination between factory-made sets or between makes of components cannot be given. 5. All letters to be signed, but a nom-de-plume may be added. avevevacete ner MURRA TAA HHA TOA NHAHMHEOTMON RB ig