Positive Feedback

Frequency-sensitive NEGATIVE FEEDBACK L-C tuned circuit oscillator). C ircuits which ure based on this principle include the Wein bridge oscillator, the Twin-1 oscillator, and the Bridged-T oscillator. Unfortunately, while the principle remains valid at radio frequencies, the feedback is much more difficult to control properly at high frequencies and so these oscillators have a typical upper-frequency limit of about 200 khz. Not all oscillators produce sine waves, and most oscillators which...

Sstv

A Taped Lecture delivered at the Congres International de T l vision d'Amateurt Armenti res, France, 1969, I am very pleased to have the opportunity to inform the participants of the international amateur television congress at Armentieres about the slow-scan television activity In Sweden and slow-scan TV in general. We are today four amateurs in this country who have complete slow-scan TV equipment, namely SM3BCV, SM5CMM, SM5DAJ, and myself, The possibility of being able also to see the fellow...

Squelch For Your Tunaverter

Noise free monitoring with adj electronic sciuelch No wires to Radio or Converter* Just coJ * For ail '500 kc outputs. 9 Or 1 . S17.50ppd Mobile Battery Eliminator, 12Vto9V S4.95ppcL Crystal Controlled models available- 1 & 2 channels with or without Squelch -26 250mcs - 12 voft neg. grd. 19.95 to 44 95. Write for details Coupling Loop & Ext. Antenna for use wuh home and Transistor Radios 3.95ppd Crystals S tate E *act L isien ing F req 5,1 Oppd Order from AIR M Al L add S.85 ea

Bti Amateur Division

SSB, CW, RTTY. Price 79500 If we had been getting the 10 volts out when the input signal was removed, then we would hold steady at 10 volts output, because 1 volt would be fed back and this would keep output constant. In fact, no matter what output we were getting when the input signal disappeared, we would hold steady at that level, because the feedback factor is just right to give the amplifier an artificial input signal developed from its own output signal-...

Your Call

Please check your address label and make sure that it is correct. In tases where no call letters have been furnished we have had to make one up. If you find that your label has an EE3*& * on it that means we don't know your call and would appreciate having it. MODEL 508 VFO SWAN 500C TRANSCEIVER 117XC POWER SUPPLY MARK II LINEAR For several years Swan Electronics has been specializing in value engineering of single sideband transceivers to give radio amateurs the best possible equipment at...

Rtty

Box 19, Boston MA 02101. X iine converters, tunable, 9v., 33. Can be crystal controlled also. Squelch unit 18 exira. Models cover 150-164, 33-48. 118-128, 144-148. 50-54, and 26.9-30 mhz. See ad on page 21, March 1969 issue of 73. Vanguard Labs. 196-23 Jamaica Avenue. Hollis.NY 11423. Teletype equipment, printers perforators, reperforators, polar relays. distributors, accessories, and converters. Aquadyne, Box 175. East Falmouth MA 02536. RTY3 converter. 850 425 175 hz...

To Modulator

Tube provided the slight increase in drive that was needed, and good results were finally obtained. All the original bias resistors were retained, and it is assumed that they are of proper value- The tank coil was rewound with five turns of number 18 wire, Vi in diameter 1 he plate blocking capacitor and the rf choke as well as the pi net capacitors were left as they were originally, and they work well. Both sections of the tube were connected to the B+, and the cathodes were grounded by a...

Let Us Try To Kelp You With Your Eng Problems

The information romp Hod herein is as accurate as can be expected, considering thai it was compiled by the editor daring the short lulls between meals, coffee breaks, staff uprisings, ham tests, and hunting trips. The prices listed may or may not be accurate, probably. Possibly not. Ditto product specifications. Uc hope you wilt find the luting helpful somewhat* Amidon Associates, 12033 Otsego, North Hollywood CA 91607 Toroid balun kit. either 4 1 or 1 1 ratio, for matching balanced to...

Dual Gate Mosfet

To 175 MHz, 19.95 ppd. to 300 MHz. 23.95 ppd. to 400 MHz, 27.95 japd. to 450 MHz. 31.95 ppd. Available from 5 MHi. to 450 MHz. Bandwidth is approximately 3 of frequency. Voltage gain 30 to 40 D8 depending on frequency. Two Dual Gate MOSFET amplifier stages with each having a tuned Input and tuned output. Each Dual Gate MOSFET U actually an integrated cascode circuit thus giving you 2 cascode circuit equivalent to 4 triodes. Exceptionally ow none 2.5 DB at l75MHz, t greatly reduced cross...

Fm

Galaxy Electronics, 10 South 34th St., Council Bluffs IA 51501, Solid state FM transceiver, 12 channels, 5 watts, 300, 10 watts, 335, both for twro meters. Two-Way Radio Engineers, Inc., 1100 Tremont St., Boston MA 02120. Motorola FM schematic digest S3,95 pp. Schematics, crystal information, alignment instructions, service hints. v nguard E1 ectronic Labs, 196-23 Jamaica Ave., Mollis NY 11423. FMT-1 two meter FM transceiver, all solid state, 13.5 vdc, six channels, 289.95, Digi-Key, Box...

Om

Dusina, W4NVK 571 Orange Avenue West Melbourne, Fiorida In Listening to some hams on the air, it appears there is still some confusion about how to tell if you have excessive carrier leakage on an SSB rig. Quite frequently I hear some ham being ribbed about his carrier leakage by listeners close to his QTH, while his signal sounds fine to me. Before going further, though, let me say there are some unreasonably critical hams on the bands, judging from a purely technical standpoint This...

To

This article is a report on a recent project that was undertaken to determine the feasibility of converting a typical eleven-meter citizen's band transceiver to the six meter amateur band. The conversion was done on a Knight C-22 that was obtained in a trade with a local CB'er. The conversion involved considerably more effort than was expected, and is not recommended for the beginner. However, the results were very successful, and this was a very rewarding project. The transceiver as it was...

Nylon

Soldering lug for the dc connection is used under one of these, and a three mil three thousandth of an inch thick sheet of fiberglass cut out to fit, larger than the plate. This helps to keep metal particles from lodging inside the tiny crack that might be there if the fiberglass sheet did not extend out beyond the plate all the way around. You can begin to see some of the detail needed at X-Band, The rf probe, input and output connectors Further reasons for the rectangular cross-section now...

Supply For C Transceiver

Model 14-117, designed for mounting under hood. Includes cables, plugs and fuses. Can operate from 117 volt AC by detaching DC module and plugging in 117 volt line cord. 130 Latest addition to the Swan-Line. High quality, high performance antennas for the teur bands. Best known are the famous Hornet banders, made in 2, 3 and 4 element models. The TB-1000 series is rated at 2000 watts, the slightly smaller TB-750 at 1500 watts. TB-1000-3 3 element. TB 750 2 2 element TB-750-3 3 element,.

Pa

Calendar clock, available in 24 hour or 12 hour movements, sell starting, indicates day or month and day of week, brushed aluminum, S40 pp. Digital clock, available in 24 or 12 hour movements, cases in charcoal gray, coral red, light blue, white, brown, or clear plastic which shows mechanism clearly, 25 pp. Ameco, Box 6527, Raleigh NC 27608. ode records for all license grades, code practice oscillators, books on learning code. 8-18 wpm record. S3,95, number...

Info

Boulder CO 80302. Ouement Electronics, Box 6000, San Jose CA 95150. Radio Shop, 48 Elm St., New Canaan CT 06840. Redline Company. Box 431. Jafl'rey NH 03452. Mini-lab, ten test instruments in one. VOM, rf lt 02 gen, at sig gen, resistor and capacity substitution, rf tieid strength, sell powered, 25 pp. Signal tracer model SI 350. signal strength meter, output speaker, rf and af amplifiers, measure gain of any rf or af stage, self' powered, Miniature AF signal...

Jsov T

Send perfect morse code from 5 to 50 words per minute. Excellent to build up your code speed Self-completing characters with automatic character spacing. Precision kit includes all parts, such as metal case and printed c fcuit boards, and detailed, illustrated instructions Pre-assembted keyboard with standard type writer key arrangement and spacing, Special characters included, such as AR SK, BT, period, comma, question markr slant bar. Self-contained battery operated two standard D cells. Alt...

Amidon Associates

12033 Otsego Street North Hollywood, Calif. 91607 1 he abundance of portables is one of the strongest points for FM, In time of emergency, you need not be connected with commercial power in any way, thus giving operation in the most extreme conditions. If you have access to a repeater, one unit could be your portable, mobile, and base station. If the repeater is out of commission during the emergency, you had better be able to go direct for maximum reliability, The usual FM portable is quite...

Ikv

NOTE INSULATE BOTH 2N174'5 FROM CHASSIS Fig. 1, Mobile power supply schematic with an RC network establishing feedback. This unit is capable of 40 watts output, 525v at 125 ma. The first unit is capable of better than 40' watts output, 325 volts at 125 Ma. It will be noted in Fig. 1. that feedback for oscillation is established by an RC network. The second unit is capable of 90 watts output, 300 volts at 300 Ma. It will be noted in Fig. 2. that a feedback winding has been added to the...

Swam

HIGHEST TRADES NO ONE ANYWHERE will beat our deal We will TOP any advertised or written offer from any other dealer. We trade on both new and used equipment and we service what we sell. Instant credit on both new and used equipment. General Electric revolving charge and Master Card Credit. L international Electronk Systems lav. 280-ARAGON AVENUE, CORAL GABLES, FLORIDA 33134 Cable INTEL 305-444-6207 Export orders our specialty as video, a sync frequency of 1200 hz is employed. A horizontal sync...

Miniature Test Laboratory

Mini-AF Generator for the laboratory or ham work bench, 10 to 100,000 hz in four bands, sine or square wave. World's smallest. IV x 3 x 4, 2 lbs Built-in AC power supply stabilized to 0,1 The output is maintained at minimum distortion and constant levei with FET oscillator and thermistor and heavy inverse feedback. Model 6803 AF Generator ONLY 59.95 RF Signal Generator AF Signal Generator Resistance Substitution Capacitance Substitution Self Powered 7W x 3 x 3 , 1941b . Thanks to transistors...