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Old 01-20-2008, 05:23 PM
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Seldom Seen Seldom Seen is offline
Hard Core 4+
Join Date: Aug 2005
Location: Highlands Ranch
Posts: 564
Default T5

Notes on the T5 section - Station Setup and Operation

Station equipment

Microphone - connected to the transmitter

- converts sound to electrical signals (an audio signal)

Speaker - converts electrical signals to sound

- if the speaker is too close to the microphone, feedback can result

- if it's too noisy for speakers, use headphones

Regulated power supply - supplies electrical power without equipment-damaging voltage fluctuations

Filter - used to block "spurious emissions," signals your radio should not be putting out on top of the desired signals

- connected to the transmitter output

- high-pass filter: lets higher frequencies through, blocks lower ones

- low-pass filter: lets lower frequencies through, blocks higher ones

- band-pass filter: blocks signals above and below a certain frequency

- notch filter: blocks signals of a certain frequency, lets all others through

- if your 2 meter band signal is coming through your neighbor's TV ("receiver overload"), use a notch filter

Terminal Node Contoller (TNC) - connects the radio to a computer of you are using packet radio

- no microphone needed for packet; your radio sends computer data, not your voice

- some computers' sound cards can also be used to connect a computer to the radio

Operating controls

Microphone gain - the "volume" of the voice signal you're sending out

- if the microphone gain is set too high, it can distort your signal

Memory - a lot of radios have memories (like a computer)

- memory can be used to save operating frequencies, CTCSS tones, power levels, etc.

Variable frequency oscillator (VFO) - controls what frequency the radio is on

- usually a knob you turn on the radio

- on some radios, you can also use a keypad to enter the frequency

Squelch - used to quiet noise when no signal is being received

Noise blanker - blocks electrical noise, like static produced by your car when you start it

Up/Down microphone buttons - used to change frequency easily

Shift control - used to adjust the offset between the transmitting and receiving frequencies

Receiver Incremental Tuning (RIT) - used to change what frequency you're listening to without changing the

frequency you're transmitting on

Step button – used to change how much the frequency changes when you tune

Function button – used when one button has to do more than one thing (like the 2nd button on calculators)


- used to extend the range of mobile or other low-power stations

- a courtesy tone is a beep the repeater makes after each transmission

- you must know the repeater’s input and output frequencies to use it

- usually, on the 2 meter band, the input and outputs are 0.6 MHz apart in frequency (the “offset”)

- pause between transmissions in case someone wants to break in

- on the 70 cm band, the offset is usually 5 MHz

- simplex: not using a repeater, just receiving and transmitting on the same frequency

- use simplex if possible to avoid tying up the repeater

- to see if you can use simplex, check to see if you can hear the other station on a repeater’s input

- linked repeaters can be used to send signals over longer distances

- to avoid interference, check with your local repeater coordinator before putting a new repeater on the air

- not all repeaters are open; some have owners who restrict access to certain users (“closed”)

Radio Problems

- three basic types: fundamental overload, spurious emissions, and harmonics

- fundamental overload: interference from a strong, close radio

- spurious emissions: putting out undesired radio signals with the regular signal

- harmonics: putting out undesired signals on a multiple of your frequency

- telephones are usually not equipped with interference protection, and its acts like a radio sometimes; install an RF

filter at the telephone

- if someone complains about TV interference: check to make sure your radio is okay; see if your own TV is

affected; chokes or filters may be needed

- if your neighbor’s Part 15 device causes interference with your radio, work with your neighbor on the problem;

politely tell him the problem and tell him the rules require he stop using the device; check your station to see if it

working okay

- whine on your mobile radio signal? Check for noise from the car’s electrical system (“alternator whine”)

- SSB garbled and breaking up? Feedback in the microphone

- signal through repeater distorted or weak? Transmitter off frequency, or low batteries, or bad location

- digital communications systems can often eliminate noise or interference

Half way there !!!!
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