Use this page to explain what various functions of a transceiver are and how to use them.
Buttons and knobs
Ham radio has usually zillions of buttons and knobs and dials on its front panel. To the neophyte, those just look very confusing and unhelpful. This script aims to clarify some of this jargon for you.
“Audio Frequency Gain”. Simply the volume control – like the one at your everyday BC radio.
“Radio Frequency Gain”. Controls the amount of pre-amplification in the RX before the first if the stage is reached. In some radios, if this is zero, almost no signal will reach the speakers and you will not able to hear anything. The idea here is that the signals you receive on your antenna can be very weak and must be hugely amplified to hear far away stations.
It is very useful in QRN (natural interference) and other noisy conditions where otherwise SSB stations become unreadable. Take the RF gain back and have a QSO (conversation) that would be impossible with full gain.
Some rigs have also a switchable additional RF gain button, which sometimes has also an attenuation function. This in effect just widens the margin of the overall RF gain.
Squelch is used to silence the loudspeaker when no signal is present in the frequency of operation. In ham radio, this will suppress the general static that remains present on most bands and is heard during breaks in the distant station’s transmission.
Squelch will not remove noise received simultaneously with the valid signal; that may only be done with directional antennas (to block interference from other directions) or filters (to block specific frequencies).
At its most basic level, squelch opens the loudspeaker when any signal is present. Another one of the several forms of squelch used in ham radios, CTCSS, requires that a specific tone be present in a received signal – reducing the probability of a repeater system being triggered by random noise, by adjacent-channel interference or by co-channel interference from DX stations intending to access another repeater on the same frequency in another city.
Passband tuning manipulates the tuning circuitry of the receiver.
- If the filter is made narrower, it allows “close together” signals to be separated – one is rejected by the filter, one is allowed to pass through. This is kind of like the equalizer on a music stereo system—you can turn the bass and treble down to hear the mids more clearly. Narrowing the passband is the best way to pick out narrowband signals (like CW and narrowband digimodes) from a noisy band.
- If the filter is set to be wider, the listener can hear signals further away from the center frequency. Imagine listening to broadcast radio on AM 790. If you have a tuning circuit that has a wide passband, you could simultaneously listen to AM 760, AM 830, etc. This can be useful when you are scanning around looking for a station.
It is similar to the IF shift (Intermediate Frequency shift), where the IF of the transceiver is shifted slightly to tune in slightly off-frequency signals.
RIT: Receiver Incremental Tuning is the ability to shift the receive frequency of a transceiver away from the transmit frequency by a small amount. Used in SSB transmissions, it was very useful in older rigs that had frequency stability problems and in current systems using some homebrew transceivers or separate transmitters and receivers.
RIT can also be used to deliberately transmit and receive on different frequencies. This is known as “working split”, with the difference in frequencies usually 3 kHz to 10 kHz.
A roofing filter is used in an HF receiver and is usually found after the first receiver mixer. Its purpose is to reduce the passband of the first IF (first intermediate frequency) to between 6 kHz and 20 kHz. This in turn reduces distortion in any amplifier and mixer circuits.
Roofing filters are usually crystal types because of the steeper filtering curve that they produce.
Roofing filters can be much narrower than 20 kHz when listening to very weak CW signals. In this case, the filter may have a bandpass of as low as 250 Hz. This also requires that the first IF in the receiver is below VHF, perhaps as low as 9 MHz.
XIT: Xmitter Incremental Tuning is the ability to shift the transmit frequency of a transceiver away from the receive frequency by a small amount. Used in SSB transmissions, it was very useful in older rigs that had frequency stability problems and in current systems using some homebrew transceivers or separate transmitters and receivers.
XIT can also be used to deliberately transmit and receive on different frequencies. This is known as “working split”, with the difference in frequencies usually 3 kHz to 10 kHz.
On top of all those knobs and buttons, you need to tune your station to your antenna, if that’s not already done. For this, you want to configure your station to send the minimum amount of power (<10W) and make sure you have an SWR ratio lower than or equal to 2.
On the air procedures
Once you have tuned your station, you can start trying to make contact, that is transmitting.
Before making your first contact
This will be routine for regular ham operators, but it should prove useful for newcomers.
- Study the band plans and propagation conditions again that allow you (or not) to operate on which frequencies.
- Review the jargon (e.g. Q signals and phonetic alphabet) to understand what can be said or how to say it!
Here’s a quick reminder of the basic steps to take to make contact:
- Tune your station to that frequency. That may mean adjusting your antenna switcher/tuner, tuning your radio to the desired frequency, etc. See above.
- Listen for a little to see if the frequency is in use.
- Start transmitting
Those procedures are the basics. “Transmitting” can vary a lot according to what band you’re on, so we have detailed explicit procedures for those two broad categories.
Channelized (VHF/UHF) operation
- Tune your radio to the channel you agreed on
- Turn off the offset (unless you are operating on a repeater for which specific procedures exist)
- Listen to see if the frequency is in use
- Key the microphone and announce your call sign and the call sign of the person you’re trying to reach:
N7TOV this is VA2ANK
- The receiving party would answer:
Congratulations, you have made contact! You can now talk on the channel, according to local regulations of course. For example, Canadian regulations require you to announce your call sign every thirty minutes and at the beginning and end of every contact.
If you can’t make contact, you can wait on the channel and announce it as such:
… or listening.
Once you are done, you can wrap up with this:
Okay Hugo, talk to you later. N7TOV, VA2ANK clear.
While VHF and UHF have the luxury of channelized operation and repeaters, the HF band is much wilder: you will need much more practice to tune your receiver to understand the other correctly. So while HF gives you a much longer range (worldwide instead of citywide), it comes at the price of convenience. But you gain incredible freedom and power.
Here, you are not limited to specific channels and can tune your frequency on the kilohertz, depending on the radio capabilities of course.
Interference is common: natural, man-made are the usual occurrence, and in fact, an interfering station may not even be able to hear you sometimes.
We distinguish between two main modes on HF: phone or CW modes.
“Phone” or voice operations
You can perform phone operations on any band except 30 meters in most places, but you should be careful to respect the informal agreements of band allocations. See the bands page for more information there. For popular DX frequencies, you should look into 3.775 to 3.800 MHz, 7.075 to 7.100 MHz and 14.175 to 14.225 MHz.
- Tune your radio to the desired frequency
- Listen in on the frequency before transmitting
- Ask if the frequency is in use, by saying:
Is this frequency in use VA2ANK
- If the frequency is not in use, make a CQ call:
CQ CQ CQ This is VA2ANK VA2ANK VA2ANK over
- If you are heard, your contact may respond with:
VA2ANK this is N7TOV N7TOV N7TOV over
- If you hear that, you can start your conversation, usually with technical (RST) details about the quality of the signal, your location, the weather, etc.
N7TOV this is VA2ANK thanks for the call. You are 5-by-9 here in Montreal and it's a beautiful, sunny day outside. The name is Antoine, how do you copy? N7TOV this is VA2ANK. Over.
Then you can have your conversation. If the contact is barely audible, you should fall back on the use of phonetics. Example:
N7TOV, this is Victor Alpha Two Alpha November Kilo, I say again Victor Alpha Two Alpha November Kilo. Name here is Antoine, I spell Alpha November Tango Oscar India November Echo. So how do you copy? Back to you. N7TOV this is VA2ANK. Over.
- USB on 20, 15 and 10m bands
- LSB on 160, 80 and 40m bands
- No phone on 30m (because of the 1 kHz bandwidth limit)
2 thoughts on “What Various Functions of a Transceiver Are?”
I need a description of all the functions of the switches and settings of the control knobs on the radio, ie. drive, plate, mic gain, carrier control and load. i am working with a TS 520 and a FT 707
I need a description of all the functions of the switches and settings of the control knobs on the radio, ie. drive, plate, mic gain, carrier control and load. i am working with Yaesu FT 707