MF-HF Equip. and Comms:
MF-HF Equipment Faults and Testing:
Which of the following conditions would be a symptom of malfunction in a 2182 kHz radiotelephone system which must be reported to the Master?
When no one speaks, then the carrier wave (made by special module in the transmitter) has nothing to module (creating radio waves), so there is nothing to broadcast, and thus no power output is indicated.
Last edited by markadlerdallas. Register to edit
Tags: none
Which would indicate a malfunction in a 2182 kHz radiotelephone system?
The distress frequency 2182 kHz has a range of 50 to 100 nautical miles during day, and approximately 150 to 300 nautical miles at night, when E and D atmospheric layers do not exist.
Atmospheric conditions may affect estimated ranges.
For more info on 2182 kHz, please see Wikipedia article 2182 kHz
Last edited by markadlerdallas. Register to edit
Tags: none
Which would indicate proper operation of a SSB transmitter rated at 60 Watt PEP output in J3E mode?
J3E is a HF SSB radio frequency. Normally, you have the carrier, and Upper Side and the mirror Lower Side.
But SSB eliminates the carrier (the frequency which voice modulates to produce USB and LSB), and also eliminates the Lower Side Band. So, you are left with only USB, called Single Side Band.
Because all you have is a SSB, then the all the radion power goes to it, and it broadcasts further.
When no one speaks, then the carrier wave (made by special module in the transmitter) has nothing to module (creating LSB and USB), so the Upper Side Band, called the SSB has nothing to broadcast, and thus no power output is indicated.
Last edited by markadlerdallas. Register to edit
Tags: none
Which would be an indication of proper operation of a SSB transmitter rated at 60 watt PEP output?
FCC defined the uses for various radio frequency ranges. It is important NOT to cross boundaries of frequencies or output power.
When power fluctuates from 0 to 60, and NOT over, then it works properly.
Last edited by markadlerdallas. Register to edit
Tags: none
Your antenna tuner becomes totally inoperative. What would you do to obtain operation on 2 HF bands?
HF.. 3,000 kHz - 30,000 kHz or 3 MHz - 30 MHz
If the antenna tuner is inoperable, it won't match impedance (in Ohms) between transmitter and the antenna, causing reflected power back to the transmitter, or other malfunctions.
In salt water environment, the whip antenna, or vertical polarization is better is the waves bounce well off the water. But horizontal wire may also work, though not as well.
Antennas may be in 1/4, 1/2, 5/8, 3/4, or full wavelengths.
ASSUMING HF frequencies of 22 MHz and 8 MHz
The 22MHz has a wavelength of approximately 13.6 meters and 8 MHz is approximately 37.5 meters. Radio waves travel close to speed of light, so 300,000 km per second/8,000 kHz, or 300/8=37.5 meters. 300/22=13.6 meters.
Since the answer is in feet, meters have to be converted to feet, and then the right fraction applied.
An antenna of 30 ft is about 1/4 wave on 8 MHz and 3/4 waves on 22 MHz.
For 8 MHz, the 37.5 meters is about 123 feet, so 1/4 is about 30 feet.
For 22 MHz, the 13.6 meters is about 44.6 feet, so 3/4 is about 30 feet.
This 30 feet is the common length for both frequencies.
Last edited by markadlerdallas. Register to edit
Tags: none
Your MF-HF whip antenna breaks off and is carried away in a storm. What would you do to regain operation on MF-HF frequencies?
MF ... 300 kHz - 3,000 kHz or 0.3 MHz - 3 MHz
HF.. 3,000 kHz - 30,000 kHz or 3 MHz - 30 MHz
35 feet is about 11 meters
40 feet is about 12 meters
300 (speed of light) / 25 MHz = 12 meters
300 (speed of light) / 27 MHz = 11 meters
Speed of light is 300,000 meters per second, but it is trimmed to 300 for the MHz calculation.
Both, 25 and 27 MHz are within the MF/HF range.
Last edited by markadlerdallas. Register to edit
Tags: none