Latest Howtobuild Data

The new 18th Edition of the famous Editors & Engineers RADIO HANDBOOK presents complete design data on the latest transmitters, receivers, transceivers, amplifiers, and test equipment. Covers SSB design and equipment, RTTY circuits, and latest semiconductor- circuits, as well as IC* Also includes coverage of r-f amplifiers, special circuits, and computers. All equipment described is of modern design, free of TVI problems,

COMPLETELY UPDATED—INVALUABLE

Provides a complete understanding of the theory and construction of all modern circuitry, semiconductors, antennas, power supplies; fuJ 1 data on workshop practice, test equipment, radio math and calculations. Includes aspects of the industrial and military electronics fields of special interest to the engineer and advanced amateur. The 1.8th Edition of the RADIO HANDBOOK provides the broadest coverage in the field—complete information on building and operating a comprehensive variety of highperformance equipment, All data is clearly indexed. Over 800 pages; 6*4 x hardbound.

CAUC I Special Pre-Pubiication Price!

%Ji\w L > ORDER NOW FOR 5PECIAL SAVINGS

No. 65168, New 18th Ed. RADIO HANDBOOK.

Special price until Dec. 31, 1969, only $11.95

(After Jan. 1, J97D, regular price will be $l3.50j

Order from your electronic parts distributor or bookstore, or send coupon below:

J Howard W. Sams & Co., Inc,t Dept. 73-10 f

4300 W. 62nd St., Indianapolis, In a. 46268 |

I □ Sendmethe new 18th Edition RADfO HANDBOOK I | at the special pre-publication price of $11.95. 1

Name

Address

I City State Zip

Chuck Hines K6QKL 861S Idlewood Drive SW Tacoma, WA 98498

Chirper

The Chirper is an automatically keyed, crystal controlled, signal source which may be used to optimize the signal-to-noise ratio of a receiving converter Homebrew or commercial, converters are a common thing around an amateur station. And, most of the VHF Tribe have read thru a jungle of esoterica dealing with low noise front ends, the velvet beauty of FET s on Two, noise generators and eternal truth, and how to copy 20 db below the noise by the selective use of liquid helium. With a kind of relentless evolution converters have been getting better and better, noise figures become lower, and the prices of suitable front end devices are dropping by the hour. But when it comes to aligning these converters the scene is one of wretchedness, A black art at best, the job is taken up with an enduring combination of blunt instrument and myth. The latter have a certain charm. Are you convinced your converter is in top notch condition because you can "hear noise" when you attach the antenna — or better yet, when you place a 50 ohm resistor across the input? Try putting a complete short across that same input Shorts aren't much good as noise sources. You U find the short gives about the same change in noise level as the 50 ohm termination. What has changed is the impedance the front end "sees". The same is partially true of the noise from the antenna. Neither is indicative of the performance of the converter Peaking the system up for maximum on either a weak signal or on noise gets you nowhere. The diode noise generator which every VHF book of substance describes is a good and useful tool when used properly. The assumption is that everyone already knows full well how to use it and does so. Few in fact do.

Fm sure you've read of it before in many places, but a little redundancy is in order. The noise with which you are concerned is the noise generated internally by the first tube, transistor, or other active device the signal encounters upon its arrival at your converter. By fiddling with the external

reactances, adjusting the voltage and current and otherwise manipulating the things soldered to the device, one may minimize the internally generated noise. At the same time the reason the front end exists is to amplify the signal. One usually desires as much amplification possible, short of smoke and oscillation, Minimum noise and maximum amplification is the game. Though the two are not quite mutually exclusive a certain amount of compromise takes place. Thus, the signal to noise ratio. When aligning a converter's first stage every adjustment effects both signal and noise. Given a constant signal source coupled into the converter thru an appropriate impedance, the job is finished when the Tont end has been adjusted for the greatest difference between signal and noise of which it is capable.

The Chirper is designed to help you do all this by letting you see what effect each adjustment has on both signal and noise. The TIS34 oscillates at a frequency controlled by the crystal. With the constants shown, that can be anywhere between 8.2 and 36 MHz. The variable capacitor must be adjusted for resonance- It isn't particularity critical but its setting peaks the rf output at either the fundamental or some harmonic. For 6 meters an 8.35 MHz crystal is used. A 9.01 MHz rock will pin the meter when the Chirper is connected into a 2 meter converter, The Amidon1 toroid is wound with No. 30 enameled, 40 turns for the primary and 5 turns for the secondary. After it is

1. 12033 Otsego St., N. Hollywood, CA 91607

The Monitor Archives 1969
NRCI's compact new happening puts you on the air with comp/ete SSB, CW, and AM coverage of the 80 through 10 meter bands. There's a lot in it for you, including built-in AC power supply and monitor speaker. Check these features, and you'll see this is the rig to stay with!

1000 Watts PEP on SSB, 1000 Watts CW, 500 Watts FSK, 500 Watts AM.

All-solid-state except for driver and PA.

Built-in RF speech clipper.

Wide-range fast attack/slow decay AGC.

Receive Vernier with separate on/off control.

Suggested amateur net price, $995.

For complete (and impressive) specifications and details, write:

'// NATIONAL RADIO COMPANY, INC.

37 Washington St., Melrose, Mass. 02176

37 Washington St., Melrose, Mass. 02176

International Marketing through: Ad Auriema. Inc., 85 Broad St., New York, N.Y. 10004

Converter J97d

AMlDOK T-5Q [Q CORE

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