Eico Transceiver

Eico Transmitter


What Ham wants to be limited to one mode of transmission when he can have all three? Or limited to PTT when he can have both PTT and VOX? Or limited to spot frequency operation when he can have 10-Kc, offset tuning each way from the transmitter frequency? These features, plus many more, make the Eico 753 a very satisfactory package for the Ham who wants the best, and at roll-your-own prices.

Although the modern sideband transceiver is a very complicated piece of equipment, it is not difficult to assemble the Eico 753. The engineering of this transceiver leaves little to be desired, and the step-by-step instructions are clear and easy to follow. At a time when so much amateur equipment is being bought factory wired, the Ham who constructs this set can feel well satisfied for he will be one of a relatively small group of operators who really know what is inside of their rigs,

The full-band coverage of the 753 actu-

Eico Model 753 Transceiver

Eico Model 751 Solid State

AC Supply/Speaker Console

Eico Model 752 Solid State DC Mobile Supply ally goes beyond the band edges; 34904010 Kcs., 6990-7310 Kcs. and 1389014410 Kcs., with LSB on 80 and 40, and USB on 20. The VFO is solid state, voltage stable on fixed or mobile operation. VOX is built in, with VOX threshold, VOX delay, VOX sensitivity and Anti-VOX sensitivity controls on the rear of the set.

The power output, 120 watts PEP, is ample to drive any linear amplifier, and when used barefoot will give an excellent account of itself. ALC is high level dynamic, and will control splattering and flat-topping as well as linear amplifier loading. The 6; ratio dial makes it easy to go from one end of the band to the other, and the 30:1 ratio is available for vernier tuning anywhere in the band.

The power supplies are very easy to assemble. If you have both the AC and DC, they can be permanently installed in house and car, and the 753 used in either location simply by attaching the cables.

Write or phone us. Here is a value it will be hard to beat.

Kit $189.95


Adirondack Radio

Ward J. Hinkle, W2FEU, Owner 185-191 W. Main St., Amsterdam, N.Y. 12011, 518-842-8350 J

Eico Ham Radio Kits

Jim Fisk W1DTY RFD 1, Box 138 Rindge, N.H. 03461

Heathkit SB-610 Monitor Scope

Are you interested in what your transmitted signal really sounds like at the other end? Is your new linear amplifier really linear or is it generating a raucous racket that is interfering with other stations on the band? And if it is nonlinear, what is the cause, improper grid bias, incorrect loading, regeneration or parasitica? Well, there is no one magic black box that will give you all these answers, but the correct interpretation of the patterns produced by the Heathkit SB-610 Monitor Scope come very close to it.

The SB-610 has proven to be extremely

SB-610 Specifications

Vertical Ymplifier Input resistance: 100 kilnhms Sensitivity ( for 1 Incli deflection): Untuned: HTTW i volt nominal

20 kHz—455 kHz, less than 500 mv Tuned: 455 kHz, 70 mv nominal

1600-2500 kHz, less than 200 mv 3000-8400 khz, less than 500 mv 5000-6000 kHz, less tltfrn 700 mv

Horizontal AmpIifier

In put resistance: 1 megohm

Sensitivity {for 1 inch deflection): 800 mv

Tone Oscillators

Frequencies: Approximately 1500 am! 1950 Hz Output voltage: 50 mv


Frequency coverages? 1.8 MHz through 51 MHz, 50-75

ulim coaxial input Signal power limits: 15 watts to I kilowatt Power requirements; 120 Vac 50/60 Fi/_, watU Dimensions: 6 H \ 10 W x I),

valuable around mv shack and its versatility w •

appears to be limited only by the ingenuity of lhe user. The engineers at Heath planned way ahead when tiiey had this iilile jewel on the draw in ¡Li board. Besides monitoring the behavior of your favorite linear, it will give you some insight to almost anv tvpe of transmitted signal, he it AM, C\\\ RTTY, or SSB. You can also check the other fellow's signal by connecting the Monitor Scope to your station receiver Additional parts are included in the kit sn that the vertical amplifier section of the scope may be tailor made to fil your own particular requirements.»

For monitoring RTTY signals and with receiver i/s up to 150 kHz, the vertical amplifier is an untuned arrangement with a resistor as the plate oad. For ifs of 455 kHz and above, the necessary if transformers and tuning capacitors are included in the kit. By changing tiiese componentsj the Monitor Scope may be used with just about any if from 455 kHz up to 6 MHz,

In addition to monitoring duties, when the vertical amplifier is wired for use to 150 kHz, the Monitor Scope may be used as a conventional oscilloscope- Its vertical sensitivity is Somewhat limited in this applicaton, but for many purposes it is perfectly suitable. Here again the design engineers have come through with flying colors, providing much of the circuitry found in many bench-type oscilloscopes, including adjustable sweep and synchronization.

The Monitor Scope is easy to build and a snap to use. With the excellent guidance pro-

vitled in the instruction manual, even the inveterate novice can make some pretty sound deductions about signal quality. The manual is liberally illustrated with typical scope patterns; each is discussed in detail and if it is indicative of poor signal quality, some ol the probable causes are listed* For monitoring with the station receiver, a series of patterns in the manual show the ell'« c I of receiver handpass and avc action on the received signal. These should be considered when making on the air checks.

Although designed for use on the ham frequencies from 1-8 MHz to 54 MHz, excellent results may be obtained up to 100 MHz. The Monitor Scope can be used on two meters, but there mav be some distortion of the pattern. The unit will safely take a full kilowatt and will operate properly down to about 15 watts. A step attenuator on the rear panel provides up to 2-1 dB attenuation when adjusting the scope with a particular transmitter or linear amplifier.

For testing single sideband transmitters, a two tone test generator is built in. The frequencies of this generator, approximately 1500 kHz and 1950 kHz. have been chosen so that their second harmonics fall outside the normal audio passband of modern ssb transmitters- It is the attention to small details such as these that really make the difference when making qualitative measurements.

One of the problems with many monitoring scopes is that during receive periods the scope trace remains stationary in the center of the CRT. If the trace is not turned off to one side of the face of the CRT it will eventually burn a hole in the phosphorus. In the Monitor Scope however* the Heath engineers have come up wTith a neat solution to this problem. In their circuit a clamp tube is used to move the trace over to one side of the i ^KT. his clamp tube mav be controlled manuallv, or ifi u t C3 m t~i (r' _ ^

when the scope is operated in either the RTTY or RF Trapezoid mode. In the automatic position, a sample of the transmitter rf power is rectified and used to turn the clamp tube off, thereby restoring the trace to the center of the CRT. Usually about 100 watts is necessary to provide enough rf for this purpose; for lower input power levels it is necessary to use the manual mode.

For monitoring or checking any type of amateur transmitter, it is hard to beat the SB-810 in performance and cost. Whether it is used at the bench in testing equipment or in your shack for on the air checks, you wi find it to be a very useful and worthwhile addition to your station. - * . W1DTY

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