The Denson Electronics Corp

Post Office Box 85 (203) 875-5198 Rockville, Connecticut 06066 ago just a courtesy to let you know before they sent it away. And then the absurdity of hoping not to get any mail for ten days, because if you don't get any mail it will mean that you passed Like a sort of undercover organization if you don't hear from us, everything's O.K. We amateurs are being asked to upgrade ourselves. I think the F C C. ought to upgrade itself, too, in respect to the radio amateur. We should expect and demand...

Supply

39 firtimore Aw, AjhwHIe, N.C. 28801 Available from 5 MHi. to 450 MHi, Bandwidth is approximately 3 of frequency. Voltage gain 30 to 40 DB depending on frequency. Two Dual Gate MOSFET amplifier stages with each having a tuned input and tuned output, Each Dual Gate MOSFET is actually an integrated cascode circuit thus giving you 2 cascode circuits equivalent to 4 triodes. Exceptionally low noise (2-5 DB at 175MHi.)t greatly reduced cross modulation and 10 times the dynamic range (signal handling...

Vert Sars

Fig.2, Oscilloscope patterns at audio output jack. 12 volts from the White frequency position on the Modulation function control drives the sub-carrier oscillator from 1500 Hz to 2300 Hz. In the Grey Scale position, the voltage is manually adjusted from y positive 12 volts to near 0 volts which in turn shifts the sub-carrier oscillator to any frequency between 2300 Hz and 1500 Hz (White to Black), Several fixed vertical bars are generated when the Modulation control switch is in the Bar...

H V

Unlike the usual noise clippers or limiters. the 34-NB is an advanced noise blanker which actually mutes the receiver for the duration of the noise pulse. Between noise pulses, full receiver gain is restored. (The receiver AGC is affected only by the desired signal strength, not by the noise at the antenna.) Low level signals masked by noise impulses without the noise blanker can be copied when the blanker is used. The 34-NB is a must for the mobile operator A noiseless electronic series switch...

Letters

The article VSWR-An Outmoded Parameter by VE2AXQ in the April 1969 73 Magazine may offer a new cause for you and 73 Magazine. in the article the author proposes to do away with VSWR on the ham bands where he says it doesn't belong and .relegate it to the microwave bands where it does belong, according to VE2AXQ. One can hardly argue with VE2AXQ s contention that there is no room for VSWR on the ham bands and I'm with him and in favor of banishing trouble with that dern VSWR and even plain old...

An Appliance

Hundering across the airways and reverberating from speaker cones throughout the length and breadth o haipdom has come, like the piercing wail of a cow with a stepped-on udder, yet another epithet with which to flail and degrade an ethnic group within the amateur radio fraternity, i.e., You You You Unspeakable appliance operator, you By over-simplification, an appliance operator is one who does not build his own equipment. He allegedly has the intelligence of a mentally retarded and recently...

Current Used Gear List

Central Electronics 100V xmtr S329 Drake 2B Receiver with 2BQS speaker and crystal Eico 753 Xcvr with 752 DC Supply 149 Galaxy 300 Tdband transceiver with AC power sup Globe Scout 6e0 AM CW transmitter 39 Gonset GSB-100 SSB AM CW i ransmitrer, 1 79 Hailicrafters HT40 AM CW transmitter___________ 49 HallicraftersP-150 AC Sply Speaker Consoie -S59 Hammarlund HG100 Receiver w Spoaker S119 Hammarlfund HG110C Receiver w Speaker , 139 Hammarlund HG145X General Coverage Hammartund HQ170C Receiver w...

Miniature Af Generator

Mtni-AF Generator for the laboratory or ham work bench. 10 to 100,000 Hz in four bands, sine or square wave. World's smallest. VAx 3 x 4, 2 Ibsf Built-in AC power supply stabilized to 0 1 , The output is maintained at minimuhn distortion and constant level with FET oscillator and thermistor and heavy inverse feedback. Model 6803 AF Generator - ONLY 59.95

Denver Crystals

4 NEW TUNAVERTER LINES & SQUELCH Tunable and crystal controlled RF converters for monitoring Police, F ire. Amateur. CB. CD. V H F weather, etc., on your broadcast radio economical See lining of models in Mar. tssue of 73, page 21. HERBERTSALCH & CO, Woodsboro 7, TX 78393 Placc the vtvm probe in J-401 and adjust Z-401 for maximum deflection. Then back it off untiJ it is reduced to 2 3 of its maximum value. The reading should be approximately - 3.5 volts. Next, place the probe in J-402,...

Ragio Amateur

Dept 925 Sherwood Drive Lake Bluff, III 60044 These vatuable EXTRA features include. in tioth editions, Census of Radio Amateurs throughout the world World Prefix Map International Radio Amateur Prefixes Over 283,000 QTHs in the U.S. edition See your favorite deafef or order d ru t (add 25C for mailing in U.S , Possess-oris & Canada, Eis& wbere add Radio Amateurs' Prefixes fay Countries output-to-input feedback, so this circuit won't oscillate any more readily than would a pentode stage....

The Dura Tower

Designed specifically for the Radio Amateur 60, 70, and 80 Foot Til+over Towers No guys All Models Sett Supporting All Welded Construction Using 55,000 PSI Heavy Wall Steel Tubing The Dura Tower Will Support Any Quad or Tri Band Beam and SURVIVE An 85 MPH Wind Erection Aids Will be Loaned Free of Charge For More Infermaf on on this low cost, high quality tower wrife

Out

Tion near the plate lead until no output is obtained when the two meter drive is removed. At full power, there should be .2 MA of grid current between R3 and ground. The transmitting unit is now complete and will deliver better than a watt of output power. 1 haven't attempted to modulate either stage of this converter, relying solely on the modulated two meter signal for audio. The result is a weird form of AM mostly downward modulating) but seems to be cop-iabte on any receiver. For the...

Desk Namecall Plate

Your name and call a nut grained desk plate 10 long by about 1 high. Up to 20 letters and spaces. You can have vour full name or your first name and call let ters Sorry, no available. Identify your station with a beautiful desk plate REDLINE Co. Box 431, Jaffrey NH 03452 ( ) 24 Hour clock ( ) Travel clock radio ( Digital clock radto 12 Hour digital clock Desk name plate Fig, 5. Another example of the Periscope'' antenna system, A question often asked with regard to using small transmission...

John

19 ALLERTON ST., LYNN, MASS. 01904 P. O. BOX 62, E. LYNN, MASS. 019M TELEPHONE DIALERS (2) Prestodial, Stores 36 telephone numbers and automatically dials any one at push of button. New S119. Richard IM. Jacobs, WA0AIY 4941 Tracy KCMO 64110. ELECTRONIC TEST and Communication Equipment-Bargains galore Send 25 cts for catalog. Palen Electronics, Box 1536, San Meteo, California. 04401 SELL Four-volume set of USAF books on hundreds of military, commercial surplus test sets 1,500 pages on 'scopes,...

Shack

1966 HILLVIEW STREET SARASOTA, FLORIDA 33579 TEL (813) 955-7161 ANSEL E. GRID GRIDLEY, W4GJO Geoige A Wilson, Jr , WIOLP 31 8 Fisher Street Walpoie. Massachusetts With no apology to Aldous Huxley.1 the litle of this article describes my intention and purpose quite adequately This article will up-dyte an article published in the September, 1963, issue of QST and, as in the case of Brave New World Revisited, we must report changes that have materialized seemingly before their time, I he previous...

Info

The positive horizontal sync pulse is 5 ms long. The Dot-Bar oscillator (Q7 and Q8) output frequency is manually adjustable from approximately 7 Hz to 80 Hz. This signal is amplified by Q9 and is connected to the Modulation Switch Dot-Bar position. The 1500 Hz SSTV sub-carrier oscillator (Q12 and Q13) output is amplified by Q14 and is connected to the low pass filter through the step down transformer Tl. The low pass filter rounds off the square wave output from...

Mi

Some magazine articles, are so heavily loaded by the transistors that the operating Q maybe closer to 3 than to the 15 or 20 needed for harmonic suppression. A tripler should he used as a tripler not a combined doubler tripler and quadruple since only the tripled frequency is useful. The same reasoning holds true for doubler and amplifier stages, The crystal oscillator is a type that will function with either 8 or 24 mhz crystals for output at 24 mhz. The slug tuning adjust -mcnt is more...

Compressorpreamp

30 db compression range Low-noise FET input stage 5-transfstor and 1-diode circuit Adjustable input and output levels Printed circuit construction with easy-to-follow instructions m 3-way jacks for PTT operation Easily installed in mike line Other Kits Audio Amplifiers Power Supplies Test Equipment Treasure Locators and many others FREE Date steels with circuit description diagram, and specifications tor aft kits P.O. 8ox 327 Upland. California 91766 Phone 714-985-15-40 P.O. 8ox 327 Upland....

Frequency

Fig 12, Response of discriminator as frequency is varied above and below center frequency'' for which circuit is adjusted. Output swings either positive or negative depending upon direction of frequency swing As the frequency of the incoming signal is varied around the center frequency for the circuit,output voltage will follow the S-shap-ed curve shown in Fig. 12. So long as the frequency variations are limited to the straight part of this curve, they will be translated linearly to output...

Radio Amateur

B, 925 Sherwood Orive Lake Bluff, III. 60044 S. Kelly, W6JTT 12811 Owen Street Garden Grove, California 92641 Recently there has appeared on the surplus market, and through MARS channels large quantities of a unique vhf I M transceiver called the AN VRC-19. The three versions if this set all cover the same frequency range I 52-174 mhjz , but they differ in their input power requirements. The most commonly encountered version is the AN VRC- 19 X which is the 12 volt model. The set consists...

Sstv Black And White

Louis I Hutton, K1YZZ . 2235 SE 62ND Si Bellevue Washington 98004 For a two year period 1967-1968 i was gran till permission by the FCC to conduct experimental tests with other amateurs authorized for SSTV transmissions on the Hi bands. This is a relatively new mode of communication and has only recently been made available for general amateur use. The interested amateur will soon find that he must construct his own SSTV equipment in order to enjoy this new mode of communication. The first item...

Fig

1 Possibility Ohmmeter reads approximately 200K ohms. System is OK. 2 Possibility Ohmmeter reads very high, in megohms. Twin lead is open ' a similar flat line, Steeleore, number 214559. A somewhat more expensive line by Amphenol is their number 214-022, which has two number 16 conductors and is suitable for transmitting amateurs- Other makers offer copperweld twin-lead under such names as lifeline ' If doubt should exist as to the wire's having a steel center or core, a small magnet will give...

Otsego Street

R C Primer 2nd Edition by Howard Mc-Entee, Kalmbach Publishing Co., Milwaukee, Wisconsin, copyrighted 1964. Model Airplane News R C Digest published by Air Age, Inc., 551 Fifth Ave New York, N.Y. 10017 2 . American Modeler, published monthly by Potomac Aviation Publications, Inc., 1012 Fourteenth Street, N. WM Washington, D. C 20005. Howard McEntee, Radio Control Editor. This publication includes the official publications of the AMA. Flying Models, published monthly by Rajo Publications, Inc.,...

Or Ohmite Z

Fig 1. The schematic for The six meter Tinear amplifier. Purists may frown on some of the preceding, however there are good reasons for it-The passive grid circuit will accommodate any reasonable drive level and while wasteful at high levels it should be remembered that linears are for use only when required to maintain communication. It also eliminates neutralization as well as several parts. The shunt fed tank also makes for simpler, less expensive, and easier...

Ralph J Irace Jr Productions

Box 210, Farmington, Conn. 06032 To sell instant Gourmet kits. These unique black leather kits are filled with eight individual containers of special seasonings. A good salesman should sell 1000 of these a month, and earn a very good commission. Send your credentials to Instant Gourmet Peterborough, N.H. 03458. The RCA 2N5188 power transistor is a recent type rated at 4 watts maximum dissipation and is available for 55 cents apiece. It was designed for core-driver and line driver as well...

Wqur

Tell Our Advertisers You Saw It in 73 While working with Integrated Circuits, I soon found that some means of mounting the IC s had to be devised because I I the leads on an IC are much too small to work with conveniently and 2 if I soldered directly to the IC, I would probably have destroyed it after a small amount of experimenting, because of the heat. I was fortunate because my first contact with ICs was through Kaye Engineering's integrated circuit kit which contains two Fairchild uL9l4 and...

Model

The Waters 3002 Phone Patch is so precision-perfect in operation you can actually patch without monitoring Its bu ft-in Compreamp Increases the level of weak phone signals. The Compreamp operates independently a a pre-amplif er l miter with the station mike, Has provision for connection of a tape recorder to record your QSO's. Front panel is reversible to permit vertical or horizontal mounting. Pius other features . ,

Products

The Mosley CL-36 is a three band 10-1520 six element beam. The gain on this monster is rated at 9db on 10M, and 8db on 15 and 20M, That's good This is the famous old Mosley TA-36 beam with their new balanced capacitive feed system, which resists corrosion much better than the older types. Weighs 69 pounds and costs under 175. It will handle maximum power on all three bands. Epsilon Records has just announced that they will henceforth have their code practice course available not only on good...

Am Eco Pt

Aerotron Radio And Power Supply

- 6 THRU 1G0 METERS FEEDS 2nd RECEIVER Model PT, with built-in power supply, transfer relay, connecting cables, wired and tested. A frame grid pentode provides low noise figure with ability to handle strong signals, greatly improving the sensitivity of the receiver section of a transceiver, A unique built-in transfer circuit enables the PT to by-pass itself while the transceiver is transmitting. The PT also feeds the antenna input of a 2nd receiver as well as DIVISION OF AEROTRON, INC, gt P. 0....

Intelligent Tube Substitution

Sooner or later, any ham finds himself in a situation where a vacant tube socket must be filled, and not with the same type tube, Examples would he 1 during a contest when Murphy's l aw dictates that the only tube to burn out will be the one for which there is no spare, 2 a desire to usoup up a piece of gear, or 3 it's so old it's hard to find a replacement. 1 have been at I three routes, so present herewith my advice on selecting suitable substitutes. Probably the first consideration is that...

Solid State Mini Af Generator

Fully transistorized sine and square wave generator, 10 Hz to 100 kHz in four bands. Smallest in world 7W x 3 w x 3 , 1.9 lbs. An FET oscillator with a thermistor and intensive reverse feedback maintain the output at minimum distortion and constant level less that 0.3 200 Hz-100 kHz and less than 0.8 10-200 Hz . The power supply is built in 100-120 vac 50 60 Hz and is stabilized to 0.1 against line voltage fluctuations. Square wave rise time 0.2 ps. Output impedance 600 ohms 100 ohms...

Globe Galaxy

Km 500 Xmtr S225 SB-1 75 SSB Xmir 59 755A VFO 29 Galaxy 300 Xcvt 129 PSA-300 AC Sup 39 G-300 DC Supply 69 Galaxy ill Xcvr 169 Galaxy V Xcvr 239 Galaxy VMk II 259 Galaxy V Mk 111 279 AC-35 AC Supply 6S AO400 AC Supply 75 RX-2 Special VFO 59 5035 Speaker 12 UM-1 Modulator IS F-3 300 cy.fiIter 24 Re ector 9

Miniature Signal Tracer

350 Signal Tracer

This is by far the single most valuable piece of test equipment for servicing receivers and audio equipment. Built in meter for measuring gain of each stage under test. Easy to find weak or defective stages. Output speaker built in or to VTVM or scope, No line cord since it is self powered. Model SE-350 Siynal Tracer-ON .Y 22.50 Buy DGP Miniature Test Equipment from Your Local Distributor or Order Direct Mail from REDLINE CO. JAFFREY, NH 03452 Please allow a little extra for postage charges....

Fo

Vari Loopstick

Have you ever wanted a small bfo to receive CW or SSB on one of the many multiband transistor portables which are available on the market today Many articles are available which state Ci Simply modify an old if transformer as follows, etc., etc ' Attempts to remove the built-in capacitor or simply cut the unused and unnecessary winding from a miniature transformer is enough to drive a good man to drink. By the way, that drink doesn't help a large unsteady hand cut that elusive 42 wire from a...

Uiba

Warshaw, a technical supervisor with ITT World Communications, Inc., whose address is 544 State Street, Brooklyn, N.Y 3 1217. If youVe interested, he can provide details on how to join. The major effort carried on by the AAV SO group is a continual recording of SEA and SES effects, as a part of the international Solar Flare Patrol efforts originated during the IGY in 1958. They use, for the most part, a simple transistorized receiver operation at about 21 kc which was designed by Warshaw. The...

Coax Cale

Complete operating data on the uses oi the grid-dip oscillator is contained in the revised second edition of this book by Rufus P. Turner. It tells in clearly written text with Complete operating data on the uses oi the grid-dip oscillator is contained in the revised second edition of this book by Rufus P. Turner. It tells in clearly written text with easy to follow diagrams and illustrations how to check LC circuits, linear and coaxial tanks, how to convert a signal generator or rf test...

Prestel Field Strength Meter

It Frequency Range 40 to 230 j i and 470 o 860 Megahertz. Calibrated outword from 10 io 50,000 Microvolts, Nothing ma Ices t easier to properly and speedily find the correct place to install TV, FM and Com munica ion Antennas, Yo u can measure and hear the signals with this 4 2 volt battery economically powered unit. Th ere s nothing else tike Itl WIRE, WRITE, PHONE COLLECT WE PAY FREIGHT ON ALL PURCHASES WE MAKE 548 Broadway, New York, New York 10012, Phone 212-925-6000 'Altec-Lansing P,L...

The Vibroplex

Y. 3, N.Y. the inverting output produces a negative-going output. Thus, the same value and polarity voltage applied to both inputs will produce no output. Fig. 1 shows the use of a Motorola MCI 533 operational amplifier, but almost any similar unit will suffice, A number of inexpensive 'surplus 1C operational ampli-Hers are available from such suppliers as Poly Paks, Lynnfield, Massachusetts 01940- Other units may differ in their voltage require merits and roll-off...

Seiler Oscillator

This article will describe a transistorized vfo to cover the amateur high frequency bands from 3.5 to 30 mhz it is designed to drive small transmitters such as the DX-40, which have provisions for vfo input and i 15 vac output for a tr switch. Construction details and sources for obtaining parts are given to aid the home-brewers. Fig. 1 shows the oscillator circuit. This is a Seiler oscillator using the popular MPF-1 02. This transistor lias a minimum effect on the frequency of the tuned...

Trouble Shoot Your Antenna from

Neil Johnsonf W20LU 74 Pine Tree Lane Tappan, New York 10983 W ould you like to shoot trouble on your - V or short-wave antenna without going outdoors It can be done, without the need for any complex instruments. The cost Just a few cents. Here's how it's done- Assuming your antenna feeds into a transmission line of the 300-ohm type-this applies to most installations-the trouble shooting setup becomes simplicity itself two carbon resistors, plus an ordinary ohmmeter Fig. 1 . Two composition...

Poly Paks

BOX 942 A LYNNFJELD, MASS 01940 wanted Gonset iii, 3357 VFO, Manual for 3226 VFO For sale, measurements Model 59 GDO Like new S135.00. J. Gysan, 53 Lothrop St., Beverly Mass. WANTED 100V, 200V, GSB-100, 32S-1, 32W-1, SSB-100F, HT-32 B , RV-3, T-4 X B in good to hxable condition, Jerry Matone W0MII I, 27 Maple Ave., Cambridge, Mass 02139. HAM A RAMA. The 5th Annual Wood County Ham-a-rama will be held Sunday July 6th at the Farrgrounds in Bowling Green, Ohio, Contact WB8AYY, Bradner, Ohio...