I’m going to lump several sections into this one post. Several questions were added and several updated, but nothing really major was changed….Dan
Once they get their licenses, most Technicians purchase a VHF/UHF FM transceiver. This type of radio allows them to use repeaters and participate in public-service events.
To use repeaters, you need to know how to set up your radio. Repeaters receive on one frequency and transmit on another. You program your radio so that it receives on the repeater’s transmit frequency and transmits on the repeater’s receive frequency.
The difference between the transmit frequency and receive frequency is called the repeater frequency offset. Plus or minus 600 kHz is the most common repeater frequency offset in the 2 meter band. (T2A01) Plus or minus 5 MHz is a common repeater frequency offset in the 70 cm band. (T2A03)
Repeater operation is called duplex operation because you’re transmitting and receiving on two different frequencies. When the stations can communicate directly without using a repeater, you should consider communicating via simplex rather than a repeater. (T2B12) Simplex communication is the term used to describe an amateur station that is transmitting and receiving on the same frequency. (T2B01)
To help amateurs operating simplex finding one another, frequencies on each band have been set aside as “national calling frequencies.” 446.000 MHz is the national calling frequency for FM simplex operations in the 70 cm band. (T2A02) 146.52 MHz is the national calling frequency for FM simplex operation in the 2 m band.
Because repeaters often operate in environments where there is a lot of interference they are programmed not to operate unless the station they are receiving is also transmitting a sub- audible tone of a specific frequency. These tones are sometimes called PL (short for “private line”) tones or CTCSS tones. CTCSS is the term used to describe the use of a sub-audible tone transmitted with normal voice audio to open the squelch of a receiver. (T2B02) If your radio has not been programmed to transmit the proper sub-audible tone when you transmit, the repeater will not repeat your transmission.
All of these choices are correct when talking about common problems that might cause you to be able to hear but not access a repeater even when transmitting with the proper offset: (T2B04)
• The repeater receiver requires audio tone burst for access
• The repeater receiver requires a CTCSS tone for access
• The repeater receiver may require a DCS tone sequence for access
One of the controls on a VHF/UHF transceiver is the squelch control. Carrier squelch is the term that describes the muting of receiver audio controlled solely by the presence or absence of an RF signal. (T2B03) You can set this control so that you only get an audio output when receiving a signal.
Microphone gain is also an important control. The reason for this is that the amplitude of the modulating signal determines the amount of deviation of an FM signal. (T2B05) When the deviation of an FM transmitter is increased, its signal occupies more bandwidth. (T2B06) One thing that could cause your FM signal to interfere with stations on nearby frequencies is that you have set your microphone gain too high, causing over-deviation. (T2B07)
In addition to knowing how to set the controls of your radio, you need to know the protocol for making contacts. First, when using a repeater, it is rare to hear stations calling CQ. In place of “CQ,” say your call sign to indicate that you are listening on a repeater. (T2A09) An appropriate way to call another station on a repeater if you know the other station’s call sign is to say the station’s call sign then identify with your call sign. (T2A04)
On the HF bands, when you want to contact another station, you “call CQ.” That is to say, you would say something like, “CQ CQ CQ. This is KB6NU.” The meaning of the procedural signal “CQ” is calling any station. (T2A08) All of these choices are correct when choosing an operating frequency for calling CQ (T2A12):
- Listen first to be sure that no one else is using the frequency
- Ask if the frequency is in use
- Make sure you are in your assigned band
When responding to a call of CQ, you should transmit the other station’s call sign followed by your call sign. (T2A05) For example, if W8JNZ heard my call and wanted to talk to me, he would reply, “KB6NU this is W8JNZ. Over.” Then, I would return the call, and our contact would begin.
It’s important to always identify your station, even when only performing tests. An amateur operator must properly identify the transmitting station when making on-air transmissions to test equipment or antennas. (T2A06) When making a test transmission, station identification is required at least every ten minutes during the test and at the end. (T2A07)
As a technician, you will be able to operate Morse Code on certain portions of the 80 m, 40 m, 15 m, and 10 m bands. To shorten the number of characters sent during a CW contact, amateurs often use three-letter combinations called Q-signals. QRM is the “Q” signal used to indicate that you are receiving interference from other stations. (T2B10) The “Q” signal used to indicate that you are changing frequency is QSY. (T2B11)
FCC rules specify broadly where amateur radio operators have operating privileges, but are not very detailed. Band plans take this one step further, suggesting where amateurs should use certain modes. While consulting a band plan before operating is a good idea, realize that a band plan is a voluntary guideline for using different modes or activities within an amateur band. (T2A10)
Regarding power levels used in the amateur bands under normal, non-distress circumstances, the FCC rules state that, while not exceeding the maximum power permitted on a given band, use the minimum power necessary to carry out the desired communication. (T2A11) So, while you are authorized to use up to 1,500 W output power on VHF and above (200W on HF), you really should only use that much power when you really need it.
The basics of good operation include keeping your signals clean and avoid interference to other stations. When two stations transmitting on the same frequency interfere with each other, common courtesy should prevail, but no one has absolute right to an amateur frequency. (T2B08)
When identifying your station when using phone, use of a phonetic alphabet is encouraged by the FCC. (T2B09) Most hams around the world understand and use the NATO, or ITU phonetic alphabet. Learn it and use it.