FROM “USELESS” – IN THE RIGHT

Want to lead a conversation about “retraining” relatively useless or obsolete electronic devices in the useful and necessary. A lot of stuff gathering dust “in the bins” radio Amateur may get a second life. This is especially true in economically crisis periods, and not only the world but also a family. For example, a portable radio (transceiver) citizen’s band (CB), shown in the photo, are unlikely to even be interested in Amateur radio.

The transceiver consists of a generator and amplifier of low frequency (LF), as well as sender and receiver node with carrier frequency 26, 9 MHz. In different variants of this type of transceivers installed quartz can vary in frequency, and the transistors have the names С9013. The high-pass part is performed on the transistor VT1, two-stage ULF — VT2 and VT3; this amplifier is the most important element of the design discharge the battery.

 

When placed close to the transmitter and receiver of one set is impossible to determine the frequency; in some instances the care of the operating frequency from the nominal value up to 2 MHz. On the setting of the frequency — tuned coil core circuit. However, when adjusting the contour of a conventional metal screwdriver inevitable additional error due to the changed terminal screwdriver field in the circuit. The adjustment process required a set of non-conductive material. Therefore, in such a relatively simple design, which is similar to many radio stations walkie-talkie, in my opinion, it makes no sense to achieve the maximum matching frequency between the transmitter and receiver. I guess it meant and manufacturers of the device. Given the low power transceiver, with a precise setting of the carrier frequencies will be able to increase the range of communication for a couple of hundred meters, and in urban areas — and less.

For effective practical application of the “toys” in the home of Amateur radio I have a number of ideas. For example, to change the transceiver in the beacon, a remote alarm on the radio on the alarm is triggered (door open outbuildings, bath, wells, barn, garage).

 

 

Appearance radio station ST NS-881

 

 

A view of the transceiver after completion

 

The second option is similar to the use of the alarm button, which is constantly in the pocket of the driver-trucker — after all, they often use communication in civil band. It does not require any special skills, permits the’nadzora, and is only necessary registrations directly to the radio output power of more than 1W. If necessary, the truck driver can notify a colleague about a disturbing situation.

 

There are all sorts of other practical applications NS-881; it’s better than just “dusting” it in the bins. For myself, I did just beacon associated with the motion sensor, which by means of contacts of the actuating relay supplies power to the transceiver. But in the process, there were two difficulties, which, however, easily disposable.

 

The first difficulty: the selection of the frequency channel.

 

First, the TRX is “programmed” to transmit a signal at a frequency of 26.9 MHz. Neither the European grid frequency in the citizen band (frequency channel ends at 5), neither domestic not correspond to this frequency. The nearest channel 1C on the European grid (26,965 MHz). European channels C2—C45, D1—D40 approved for use in Russia.

 

Even if you close the switch “to transfer” and set the jumper on the button of the Morse code (that worked constantly sound generator), a signal of this beacon can only take the same “toy” transceiver. And if not, or you want the alert to the more common frequency? Have desoldering a quartz resonator and instead set a different, based on the information in the table.

 

Since the vast majority of users have transceivers with the European grid of frequencies (since it produces even domestic transceivers TAIS), it is reasonable to set such a quartz crystal resonator, which is better suited to your “professional” transceiver, if one is available (for example, other models of portable radio: “the Veda of the world Cup” — 27,1875 MHz, “Ural-R” — 27,175 MHz Pilot — channels C38 and D5 corresponding to the frequencies and 27,465 27,385 MHz). Can be other options.

After installing a new quartz resonator and fixing mode switch “reception — transmission”, as well as installing a permanent jumper on the button of the sound generating a modified transceiver NS-881 looks like photo 2.