S

Compact, high performance, all solid-state receiver for amateur applications featuring FIELD-EFFECT TRANSISTORS Developed especially for the sophisticated amateur who knows enough to demand (he finest. The DAVCO BR-30 is amateur designed and professionally engineered to provide exceptional performance under extreme environmental conditions and combines advanced design with simplicity of opera* tion. It provides all the latest state-of-the-art techniques in an ultra-compact unit (just 4h x...

Company

Woodchuck Hill, Harvard, Mass., 01451 Don Smith W3UZN 1 126 Outer Drive Hagerstown, Md. Heres an inexpensive general coverage receiver for the ham or SWL. 'Get a 150 SWL Receiver for 84.95, the ad read, Well, they'll have to show me * 1 thought as I sent ofl a check for the receiver. An ad can and often does say anything, but knowing Heath's reputation I figured I'd get more than 85 worth anyway. After building the receiver, IVe found that they're right. The GR-54 covers 2 to 30 MHz in three...

Auto Match

, , . which is to say he wants an antenna engineered to polish off the job of getting all the RF power generated in today's peppier 3SB tranceivers out , . . way out And Waters AUTOMATCH - does just that It excels on any band with only a coif change , structurally it's built to outlast rig after rig , . , car after car. Santa is pretty well stocked with the Auto-Match right now but play it safe and get an order in early.

L

LZ l 01A+1ZllLG 32T.P+L L3 - 12 TURNS ON COLO END OF L2 LA - II TURNS, 1 2 DA*. 6 T.P.I. L5 - 2 T RNS. LOOSELY COUPLED Tt> 14 First conversion section of the ideal transit puts out a stable signal on 22.5 to 23.5 First conversion section of the ideal transit puts out a stable signal on 22.5 to 23.5 (he corresponding points of course. The bulb should almost burn out, A brown head .y watt or a blue bead 1.5 watt bulb can also be used. The second conversion is shown in Fig. 5, 1 used a 60.75 MHz...

Vanguard Labs

Hollis, NX 11423 Honeywell humidify sensor used rn the Humidivo* One of the penalties we pay for switchless SSB operation is that we sometimes forget to turn the switch when it should be turned i.e., when we get up from the rig to do something else. All too often the VOX is left on and any noise made by an unwary or unwitting occupant of the room goes over the air. While it is only embarrassing to have others listening to family arguments, it can become downright illegal if...

Dhq

TWO BEAUTIFUL SYNCHRONOUS 24 HOUR ELECTRIC CLOCKS ONE FOR LOCAL AND ONE FOR ZULU OR TIME Viltr lien iOOllNO l-lll ** WDOO CAIlMtT CONTAIN* TWO t N INCH HATCHED CLOCK* WI N CH t O MC IHM tJNQl ITTUhO TO INHANCI ANT 0ON, MO HCONC HAND . lUiMINS 10 U , Ajiembfed & rented, comp to whh > iit cosTj, aar phone *nd battefy.

Bssb Transceiver

Provides Superb, High Efficiency Performance On SSB, 'THE COMF1 ET BIG STATION IN ONE LITTLE BOX Includes all power supplies & crystals. 3.5 to 30 MHz full amateur band coverage n 500 kHz segments. 500 watts pep on SSB, selectable upper & tower sideband, all bands* 250 watts d-c input CLASS C final amplifier op Hi Uvel FCA* T UnflS ISs C finG on AM (use optional B-500-AM solid-state plugin 500 watt peak class 8 modulator for gbsa- MftflMiMt ft OF AM MODULATION AT FULL RATED POWER - two...

Vfo

The pentode plate is conversion is gjven in Fig, 4, the second conversion in Fig. 5, ond the final in Fig. 6. tuned to 20 plus 24 MHz and there you are on 144 MHz. With a single 300 volt supply from an old radio you can burn out that number 48 bulb 120 mW on two meters, but when I put it on the air, I met the Gremlins Everything looked fine Plenty of drive to the final, tuned fine, image 24 MHz away, couldn't even find it , modulation great, first contacts fine. But, as...

Hrc

This figure graphically illustrates the gains and losses in a hypothetical microwave system operating on 1215 MHz, With a 30 mile path, 6 ft, parabolas at each end, a 100 milliwatt trans mitter and using RG-8 U transmission line. On the left graph scole, 0 dBm should be shown as 1 mW, not 100 mW,

5763 Doubler

Fig 3, Block diagram of the perfect two meter, superhet, double conversion transmitter. The first 144 to 146, but had less than 100 mW output. The circuit is shown- in Fig, I. It is really quite clear if you simply follow through one tube at a time The 6AF1I is actually just three complete tubes in one glass bottle, so il isii'l hard. You can dimly light a number 48 bulb on the output terminals with about 280 to 300 volts B plus. However, while the two meter output was enough to operate a 5763...

Sideband

Ideal TV transmission characteristics, modulation, the cathode must be grounded well for rf but not for video, 1 se good button bypasses of 10-40 pF. Fig. 2 shows a block diagram of the K3ADS television exciter. Two things are evident. First the transmitter is a combination of units that have appeared in print. The low level exciters are the 220 units appearing in the older editions of the ARRL Handbook.1 The visual exciter was moved to 144 MHz, In the visual transmitter, the last 6360...

Vfo Transistorschaltungen

Transistor 2n707

Transistor VFO for 5-6 MHz for SSB mixing service. - 4pF TftV fl calibration Fig. 2. Transistor VFO for 5-6 MHz for SSB mixing service. Construction of VFO using parts from a command set transmitter dial, Construction of VFO using parts from a command set transmitter dial, the VFO box and a calibration chart was made. With 22 turns, the capacitor has about 9 pF of travel, or from 8.0-8.3 MHz on the VFO. This resulted in a very stable VFO which could be tuned to...

VHF Antennas

Some hints gained from years of roof scrambling About 12 years ago, the writer built a lii meter parabolic beam antenna on the roof of an engineering building at college and has been climbing roofs ever since that time. There is a great fascination in building and testing VHF antennas and I suppose, or hope it will continue for a few more years, Nowadays it always means a sore back and legs for a week after each antenna test and pole raising effort, plus some scolding by my wife. At the moment...

Gzd

During the Christmas Season, we're offering a special for Santas 21 good back issues of 73 our choice from before 1965 for only 5. All back issues of 73 are stiil available except January 1961. They cost 50 lt f apiece except October, November and December I960, which are 1 each. Order now for fast delivery. Include postage on orders for one binders- Two or more binders and all magazines shipped postpaid in U.S.A. and Canada. Please include postage on other orders. meetings are nut a social...

If Centeh Frequency

In A, the RTTY FSK signaf is correctly tuned in a receiver with the ideal tf passbond and the BFO is properly set. In B, the BFO is improperly set with the mark signal in the if passband and the space signal out of it. The distance from the BFO to the if center should be 2550 instead of 2250 Hz. trum. Obviously, the tuning is most critical for this bandwidth. Note that the BFO should be set 2550 Hz away from the center of the if passband. It doesn't make am...

Transmitters

B amp W 5100 Collins 30L-1 near new Collins 30S-1 Collins 32V-1 anti-trip Central Elect. 100V Globe Champion 300W Gonset 500 W, Linear Gonset G5B-100 Gonset GSB-201 Heath Apache Heath DX-35 Heath DX-40 Heath HG-10 VFO Heath DX-100 Halicraf lers HT-40 Hammarlund HX-50 Johnson Viking 500 like new Johnson Viking II Johnson Ranger Johnson Valiant SI 09.00 189.00 89,00 129.00 7 79.00 169.00 249,00 229.00 229.00 95.00 159.00 39,00 99.00 179,00 35.00 29,00 59,00 119.00 369.00 99.00 129.00 199,00...

Audio Amp And Spkr Driver

Block diagram of a typical small superhet receiver without an rf stage. Most five-dollar transistor superhets closely follow this scheme, These receivers are commonly supplied with a schematic diagram. In a typical model most of them are about the same avoid reflex circuits the first transistor serves as a common-emitter mixer and a collector-feedback tunable local oscillator The next two transistors are if amplifiers at the usual near-455 kHz frequency. There is even an AGO circuit A...

Info

Here s the two meter version of Bills very popular 50 watts on 50 MHz for 50 in the June 73. We all know superhet receivers well, here's a super let transmitter, in fact three of them. Two work poorly, but one works very well. 1 uses a rock-bound YFO It's easy to build and low in cost. You too can build it, but just pay attention to all the little details. The problems facing the superhet transmitter designer are much the same as those that bedevil the multi-conversion superhet receiver man,...

Tca

Steve Stephens W9SLM RR No. 2 Sheldon, Illinois I am sure that most hams who like to build equipment are familiar with decals, Decals give that commercial look to home constructed equipment. Many times in the past, I have needed a special title or design that was not in my commercial package 1 imagine other do-it-yourselfers have also been faced with this problem. Perhaps your projects only require standard titles such as KVA, Gauss, De-emphasis, Hot Water, Tilt, etc., whereby a commercial...

Dsr

Usually unlike power transformers cannot be connected in series to obtain higher dc output voltages because no center tap is then available. This circuit illustrates a method of accomplishing this. The transformer on the positive side must have sufficient insulation to withstand the combined voltages. I he primaries of course must be correctK polarized if little or no output is obtained reverse the connections to either primary.

Streamlined Modulators for Transistor Transmitters

Presented here are two unusual methods of modulating transistor transmitters that rival the commonly used transformer coupled collector modulation technique in performance. While neither circuit is really new they both have basic vacuum tube histories , the implementation to transistor circuitry is unique Both of ihe techniques discussed streamline the modulator by eliminating the bulky modulation transformer and its attendant matching problems. Hence, the primary advantages of reduced size,...

Valu

Can search the world over, but you won't find a better value than the SB-34 and the SB-2LA. The SB-34 four band transceiver is entirely solid state, including a transformer type power supply which provides both 12 volt DC and 117 volt AC operation built-in. One look at the SB-34's specifications will prove that only 395.00 will return the biggest possible value for every dollar expended. A perfect match is the SB-2LA linear amplifier. This compact package will boost the gain of the SB-34 or any...

Bam High Power Plate

50O watt peak power, solid-state high-level plug-in plate modulator for use with the B-500-SSB and the B-33T transmitter for those who desire absolutely superb, high efficiency AM performance from our new, top-Quality SSB equipment line. Integral Power Supply Included. Not required for SSB or CW modes. Spoce is provided inside B-500-SSB o d B-33T for the B-500-AM. The B-500-SS8 simply plugs into the mount allows all wiring for mobile operation to be permanently installed in vehicle, B 2500L 2...