Tagged Feedlines

Some repeater operators were a bit piqued at the FCC requirement that remote transmitter feedlines and antennas be tagged. They felt that this would help those who might be bent on mischief to cut the right coaxial or control cables at repeater sites. They were also put out that amateurs should have to do this when business repeaters have no such mandate. The complainers were quieted by others with the argument that, after all, this isn't a serious problem - and since so many other of the new...

M Fm Transceiver Srca

Solid state, 2 watt, 5 channel hand held transceiver. NEW SOLID STATE 2M REPEATER SC-ARPT-1 DIGIPET 160 Frequency Counter 1000 Hz - 160 MHz 05 microvolt sensitivity 349.95 ppd USA NEW SOLID STATE 2M REPEATER SC-ARPT-1 Complete packaged repeater designed for today's popular 2M FM band. I2vdc. Ideal for new system or emergency portable operation. . Complete G-10 epoxy board wired and EMPORIUM SOUNDS OF POMPANO 1 ycar warran,y 51 NORTH FEDERAL HIGHWAY 19.95 ppd USA Install in just a few minutes...

Fransistorized

A perfect project for the newly liberated novice. The circuit is assembled on a printed circuit board for ease in construction. . The problems encountered in the design of a variable oscillator for use in amateur transmitter frequency control are manifold. The circuit must be stable electrically and the mechanical design must be such that the oscillator frequency-determining components are mounted in a rigid fashion. The design to be presented satisfies both requirements and utilizes a rather...

Single Conversion Two Meter Fm Receiver

Block Diagram Receiver

The following is a description of a build-it-yoursetf two meter FM receiver using two new components to achieve a single conversion job for narrow-band FM amateur use. Ft produces plenty of good, clean af from a total transmitter deviation of 10 kHz. Once again the broadcast industry has created a component of considerable interest and utility to amateurs. This is the RCA 3089E chip, in a plastic 14 pin case, x Vn x 1 8 in., containing some 63 transistors, 30 resistors, and 14 diodes. The major...

Tone Burst Decoder

Certainly many articles on repeater control have appeared in the pages of 73 Magazine. Actually, more so than in any other journal both amateur or professional. One thing that you may find interesting, however, is that these unique applications do not necessarily have to apply to FM. All sorts of applications can be devised using small signal activated timers which are accurate, reset themselves, use somewhat standard voltages, and are able to withstand continuous service at very low power...

Fet Preamplifier

Here is a simple experiment used to familiarize yourself with FET circuitry. Described is a simple forty meter pre-amp which can be used to soup up a transistor shortwave receiver or add sensitivity to an inexpensive 80 or 40 meter receiver. On several vacation trips 1 used 60 feet of wire wound on a dowel 3 8 in. in diameter, and then clamped to the car window. Without the pre-amp no signals could be heard even though a loading coil was tried, and several antenna tuning coils. Running coax...

American Amateurs May Exchange Satellite Data With German Amateurs

The FCC issued a Public Notice on the above on October 5, 1972. The text follows Information has been received by the Commission that the Bundes Post of the Federal Republic of Germany has no objection to the exchange of third party traffic with German ama teurs relating to an exchange of technical data in connection with the launch of OSCAR 6 amateur satellite and throughout its orbit period. Such third party traffic may be directed to other amateur operators in Germany only concerning the...

Vere

1.Fisk, Coaxial Transmission Line Handbook, 73, July 1966. 2. Rand,. Television Interference Handbook, The Nelson Publishing Company. Stephen J. Barns WA3CXG 126 East ffainut Park Drive Philadelphia PA 1 9120 The thought of optical astronomy conjures images not only of Mount Wilson and Palomar but also of the many thousands of amateur observers throughout the coun-tiy. On the other hand, radio astronomy brings to mind visions solely of huge installations such as Arecibo and Jodrell Bank this is...

Cxa

Specifications SENSITIVITY Better than tOdb signal-plus-noise-to-ratio for .25 microvolts at 28 MHZ. SELECTIVITY 2.4 KHZ -6db. 1.8 1 lt 6 60db shape factor. 16 pole crystal lattice Filters optional CW-300 and 400 HZ. FS K 1200 HZ. CARRIER and unwanted sideband suppression. Minimum 60db. IMAGE and IF REJECTION more than 60db. POWER LEVEL 300 to 500 watts p.e.p. continuous duty cycle. POWER AMPLIFIER 8072 final completely broad-banded driver and final, 150 watts continuous dissipation rating....

And Many Thanks

to all of you for making 1972 our biggest and best year yet We must be doing something right . . . - a San Francisco ham writes after several orders You have the best-stocked ham store in the San Francisco Bay area - a QWCA member from Dallas says So far I have received better service and what I think is better equipment than from any previous dealer. - an Iowa customer had trouble and returned his 2-meter rig for service and wrote You received it on 5-23-72, and it arrived back at my home...

Wbdbb

Upton on Severn, Worcestershire England Years ago when one modulated an 813, pair of TZ40's or whatever, it was nice when testing seemed called for to get a hearing of one's own transmission. This needed nothing more than a diode, pick-up loop of a few turns, and a minimum of other items, Fig. 1. At first 1 used to put audio into the TX mike circuit from another af source. Later, 1 used to put the diode output into a tape recorder, and afterwards listen for a minute or two to this reception of...

Or Panoramic Receiver

Panoramic Receiver

The key considerations of good receivers are high selectivity and image rejection high overload low cross modulation and low noise factor. If you built your own receiver, it also has to be rather easy to put it together and align it. The described i-f amplifier uses two crystal filters in order to give 500 Hz and 5000 Hz bandwidth. It requires no alignment work, is uncritical to assemble and provides a high image rejection in standard receiver systems due to the operation at 9 MHz. The gain is...

The Mostone Encoder

This tone burst encoder for 2-meter FM repeater access is literally built around an MOS quad NOR gate RCA CD4001 D or CD4001E , and boasts the following features Miniature size volume less than 0.5 cu. in, Very low current consumption less than 3 mA with average operating conditions during tone generation Excellent temperature stability Simplicity a dozen readily available components Versatility can be easily adapted for multiple tone operation The photographs tell the story about the...

Vernier Dial

Details of rigid capacitor mount. was a slow thermal drift each time the oscillator was turned on during a QSO. This sort of short term frequency variation is common with tube circuitry and high levels of oscillation. Drift with the semiconductor vfo is practically non-existent on both a short and long term basis. In normal operation the vfo is allowed to run continuously and a subsequent stage in the transmitter is keyed. This does not allow break-in operation aithough the vfo has been...

More Letters

It was very gratifying to see my latest article on SSTV equipment in print in the September issue of 73 Magazine. I am already receiving many compliments on it and that 73 is publishing timely articles on SSTV. From the correspondence and conversations with chaps who are building this camera I have been getting several questions in regard to the Plumbicon deflection coils. In the diagram the horizontal sync pulse drawn near Q4 is 5 m 7 seconds, not 5 microseconds. The vertical sync pulse drawn...

Nonsquirrely Two Meter Preamp

During my years of experimenting with 2 and 6 meters, I have built a number of things such as preamps and converters using tubes, nuvistors, transistors and FET's, including the well-known 3N128 Mosfet. I recently tried a circuit using an MPF-107 FET in a common source configuration. The circuit herein described, if followed closely, will produce a non-critical two meter preamp second to none. Nor is there any neutralization required. This preamp can be built on a home brew printed circuit...

Fm Inoue

. . .you are going First Cabin . . . with the trend setter for 2 meter FM A look at the IC-20 for just S269.50 Try to match these features with any 12 channels, 10 xtais supplied, individual tweaking on all 12 T amp R channels battery saving high or low power- 1 or -plug-in, shteided. modual construction, -hot revr . - less than A uV 20 db built in linaf protection circuit built in alternator whine filter helicalized cavity resonators noise canceling mike amp mbl mount inc. each rig thoroughly...