Radio mirror (Jan-Oct 1923)

May 19, 1923 RADIO DIGEST How to Make One Condenser Flivver Super Set Part III — Circuit Diagram and List of Parts Ovn lust talk on the onr condenser Plawelling circuit dlsoussed the tubing arul tickler coils for tliis sot. Those were of the varloooupler type In contrast to honeycomb coils, and the question lias arisen as to why the change was made. It really is a matter of personal choice. All Radio sets may be constructed In various ways according to the needs or fancies of the builders, and the set which we are now describing is merely another method of arriving at the successful operation of the Flewelling circuit. The circuits and sets that have been previously described have worked out very well indeed, but one never stands still and the present set, we believe, will be accepted as another step ahead. The advantage is in the circuit used and it will be seen at once that it might just as well be constructed with honeycomb coils as not, according to the builder's desires. The next step for us to consider after the inductances is what parts are to be used, and it is perhaps best to give here the complete list of parts that will be necessary to use to construct the set. The list is as follows: The inductance unit described last Issue. One bakelite panel about 9 by 9 inches and one sheet of copper foil of same size to be used to shield the instruments. One tube socket. One 11-plate variable condenser .00025 mfd. vernier type recommended. One tube rheostat, vernier type if pos-. sible. Two dials, one for the variable condenser and one for the tickler. Eight binding posts. One switch lever with 7 points. One switch lever with 2 points. One suitable wooden board to mount panel, etc., on. This board should be % inch shorter than panel to allow for mounting set in cabinet if it is desired and about 8% by 5 by % inch thick will be right for the panel size given. One variable grid leak, panel mounting type preferable. One grid condenser .00025 mfd. capacity, with mica dielectric. One mica dielectric fixed condenser of .006 mfd. capacity. Suitable screws for mounting parts, wire and clips for connections, A battery, B battery, phones and a tube. Many fans will ask just what particular parts to use, and to this question we must answer, just the best. No fear need be entertained as to whether the receiver will operate and one will be far better satisfied in the end if only good reliable apparatus is used. Critical Apparatus The only critical pieces to consider are the following, and we might offer a few suggestions regarding them: The variable grid leak is very important and should be one that has a large range of adjustment. Try to get one that is guaranteed and that may be exchanged if it does not operate properly. The best that you can buy will be the surest way to success that we know of. The gTid condenser should be of a well constructed type, that uses mica for its dielectric and one that will be easy to mount with the grid leak. In this connection let me advise the use of a combination grid leak and grid condenser that may be mounted directly upon the panel so that all adjustments of the leak may easily be made. The large fixed condenser of .006 mfd. capacity should also follow the scheme of things. This should be of good solid construction and it is important that this condenser also uses mica for its dielectric. Tube for Best Results Regarding the tube to be used with the set, the following is suggested: A hard tube such as the UV201, TJV201A, WD11 or WD12 is recommended and note also that if you wish to, you may use a soft tube such as the TJV200. In other words, use the tube that you have on hand or is easiest to obtain. A great many will ask at once which WE REPAIR WD-11, $3.50 and OTHER VACUUM TUBES Excepting VT-I and VT-II MAIL ORDERS Solicited and Promptly Attended To [ & H RADIO GO. 616 Clinton Avenue NEWARK, K. J. By E. T. Fleivelling tube is the best? There is no direct answer to this question because no two tubes are alike in their operating characteristics even though they may bear the same labels. The advantage lies with the hard tube of the UV201 and UV201A this wiring diagram of the set. Connections for the Set It will be seen at once that the variable condenser has been changed from a parallel or shunt connection with the inductance to a point where it ds in In the circuit above, I— 1 (stator) and L-2 (rotor) combined are the inductance described previously; S-l, tap switch on stator of inductance; C-l, ll-plate variable condenser, vernier preferred; C-2, .00025 mfd. mica fixed condenser; R-l, variable grid leak; C-3, .006 mfd. mica fixed condenser; S-2, single pole double throw switch when thrown to X makes set a Flewelling Super, when thrown to Y, converts set to straight regenerative; A and B, terminals for either aerial or ground, or one of these alone, interchangeable type because of the greater volume that these tubes give. If a soft tube is used, it will be found very critical when used in the set, especially if it is operating as a Flewelling set. The volume is not as great as may be wished for. This tube however is perhaps our best tube for use as a plain detector tube, it is at all times best at a critical plate voltage. Summing the tube question up gives us the answer that any good vacuum tube will work in the circuit and that the difference in various tubes lies in the volume that they deliver and in how critical they are to handle. Departure from Original Layout It will be seen by now that this receiver is going to depart a bit from the usual Flewelling layout. The reason for this is that it will enable the greatest number of fans to join the circle and also because we are finding it possible to further simplify the circuit. We all are anxious to reduce our sets to the simplest possible form and the writer believes that the set that we are describing is a real step in the right direction. For instance you are asked to study very carefully Vernier Var. Condensers COMPLETE WITH KNOB AND 3 IN. RUBBER DIAL $5.00 "Value 11 plate with 3 plate Vernier $2.00 5.50 Value 19 plate with 3 plate Vernier 2.15 6.50 Value 41 plate with 3 plate Vernier 2.50 Plain — | Plain— 3 Plate $0.75 23 Plate $1.25 11 Plate ., 98 I 43 Plate 1.50 Include 5c per item for parcel post. CHI -CITYRADIO CO. 945 CRESCENT PLACE, CHICAGO, ILL. PONT PASS THIS-BUYf I Every World ■ User Is a K ». Booster ^^V Because you deal direct with a manufacturer who is responsible for the performance and quality of the Battery. VorldRadio Batteries SAVEY0U 50% wmiKK 2YRCUAR WRITTEN 2 YEAR GUARANTEE series with the antenna, or ground, whichever is being used. That is, one' side of the variable tuning condenser is connected to the side of the inductance that is connected to the grid condenser and leak and whatever type of energy collector that is used, is connected to the other side of the variable condenser. The incoming signal goes from the energy collector, through the variable PATENT ATTORNEYS PATENTS. Booklet free. Highest references. Best results. WATSON E. COLEMAN. Patent Lawyer, 624 F Street, Washington, D. C. tuning condenser, touches on one side of the tuning inductance, goes through the fcrid leak and its condenser directly to the grid of the tube. If this variable tuning condenser were to be connected to the side of the inductance that is connected to the filament of the tube It would be useless and this is why the above emphasis is made. Used as a Super When the circuit is used as a super there will be no connection whatever to the point B on the diagram. This point is only to be used when the set is operating as a plain regenerative circuit. As a super any connection of the set to ground or antenna should be made to the point marked A. Here is a point to remember, although we will speak of it when referring to the operation of the set in order to secure any effect from the tuning condenser when using no antenna or ground it will be necessary to arbitrate and use a short antenna consisting of from 3 to 6 feet of wire or a convenient coal hod or bed spring or auto frame connected as stated to the point A. This completes the list of parts and materials needed and we will pass on to the panel layout, because we are going to try to show that there is a best position for the various pieces. Panel layout will be the next article. r (TO BE CONTINUED.) •~a RADIO "BUGS" GET INTO BUSINESS FOR YOURSELF Why not turn your hobby into money? Tou can easily make $15.00 a day, or as much more as you like, hy our wonderful plan of selling Kadio direct to the millions of people just waiting for our better parts or sets. We furnish everything you need at lowest factory prices and tell you how to build a profitable business of your own. 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