What is delta tune on a cb radio

Explanation of Radio Features

This is where one radio stands out from the others. The features incorporated into a CB radio can vary widely from radio to radio. The more expensive CB radios are packed with features, many that you will want and use frequently. Review the features and select a radio that will best fit your needs. We have listed several features available and a brief description of each function. We will try to keep this list up to date and accurate. If you notice something missing or incorrect, just let us know!

• ANL- Automatic Noise Limiter - A noise limiter clips an audio signal to reduce the amplitude of impulse noise. It prevents the waveform from exceeding a certain level.
• Bluetooth - This feature has been added to just a couple of Cobra CB radios. It allows you to use your cell phone through the CB and/or operate the radio hands-free. The Cobra® 29LXBT will also display phone information.
• CAL - Some radios include a meter that will allow you to CAL or Calibrate the antenna during the antenna tuning process.  Remember, every CB antenna needs to be tuned to its application to optimize the performance of the system and to help ensure that radio damage does not occur from operating with high SWR.  Check out our Help Center Article How to Tune a CB Antenna.
• Channel Scan - Allows user to scan through all channels for activity (someone talking/transmitting). Some CB radio models also include the ability to scan a smaller number of channels stored in memory.
• Clarifier - If you need to tune a frequency in just a little more, the clarifier on the DX959 will adjust the frequency up or down (12 o'clock on the dial being no adjustment) up to 1 KHz.
• Delta Tune - Some CB radios have a Delta Tune feature. This feature was originally for older crystal based CB radios and would allow you to fine tune the frequency that you are receiving on. Modern CBs are more tolerant and more frequency stable so it is not as important as it used to be. For your modern CB, we recommend leaving this set on the center.
• Dimmer - If your radio has lights, this feature will allow you dim the radio lights.
• DSC - Digital Selective Calling.  A VHF radio standard for communicating among boats and sending automated distress calls.
• Dynamic/Mic Gain - This feature allows you to adjust the modulation of the radio. Essentially, it allows the user to adjust the voice output transmission for the microphone. This is a handy feature because some users who talk loud or soft can adjust it to compensate for their voice. Make sure not to adjust to off position or no transmission will come through the microphone.
• External Speaker Connection - Most CB radios include an external speaker jack on the back of the radio. This feature allows you to plug in an external CB speaker that can be mounted in vehicle to allow better reception. The internal radio speaker is dis-abled when an external speaker is used.
• FIPS - Federal Information Processing Standard.  A set of location codes roughly equivalent to your county codes.
• GPS - Global Positioning System
• Instant Emergency Channels - Back in 1969 channel 9 was designated for emergency transmissions by the Federal Communications Commission. For easy access most manufacturers have incorporated a channel 9 switch to aid users and provide instant channel access. Channel 9 is monitored by many REACT and emergency type organizations. Many Base Station operators also monitor Channel 9.
• Lights - Many CB radios have a back-lit face, lighted meters, or LED channel indicators or displays. They often have names like "Nightwatch" or "Starlight". Whatever the name, the effect is that the face of the radio, or part of it, is easier to see in the dark. Some models will have on/off switches, high/low switches, or dimmers for these lights. Many now offer multiple color faces that can be changed by user to match vehicle interior dash lights.
• NB Noise Blanker - Reduces the effect of certain kinds of radio noise on a received signal.  Can be effective at reducing noises from lighting, automotive ignition systems, and other impulse-type noises. 
• PA - Most CB radios come with a PA (public address) switch on the front of the radio and have a jack on the back of the unit which enables connection of a PA horn. This feature allows user to instantly switch from the internal CB radio speaker to a PA horn mounted on the outside of the vehicle which is usually mounted under the hood. When in the PA mode the radio transmissions will broadcast over the PA horn instead of over the air. Keep in mind that if you require an extremely loud PA system that this feature will not meet your needs (Loud PA transmissions require an amplified PA system).
• RF Gain - This is the most important feature to have on a CB radio. This function allows the user to open/close the receiver to quiet the radio without utilizing the squelch control. By utilizing the RF Gain control to quiet the radio instead of the using the squelch control a greater receive distance can be achieved. See this guide to RF gain on a CB radio for more a detailed explanation.
• Roger Beep - This feature is available on the higher end CB models. When transmitting, your radio will emit and audible beep over the air each time you release (un-key) the microphone key. The idea of this feature is to inform the receiver that you are done speaking. Most of the Galaxy CB Radios incorporate this feature.
• Sound Filters - Many CB radios include one or more noise filters. The purpose of these filters are to reduce or eliminate engine whine, static and atmosphere noise. These filters are referred to as ANL (automatic noise limiter), NB (noise blanker), SoundTracker, etc. The net effect is to enable clearer reception. For more information regarding interference, check out our Help Center Article Troubleshooting Electrical and Engine Noise
• Sound Tracker® - “Cuts noise coming in...strengthens signals going out. This Patent pending technology dramatically improves transmission and reception of CB signals. The revolutionary SoundTracker® System reconfigures the transmission signal which allows it to be transferred more efficiently through cluttered airwaves. At the same time, it significantly reduces the amount of static on all incoming CB signals. The end result is a cleaner, clearer sounding reception of signals and a more powerful transmission which dramatically improves CB communications."Cobra®
• Squelch - Every CB radio incorporates a squelch control. This function tunes out the static and weak signals. However, using the squelch to quiet the radio reduces receive distance.
• S/RF Meter - Some radios include a built-in meter with this feature that will show you the transmit power and recieve signal strength.
• SSB operation - Without getting too technical, SSB (Single Side Band) operation is a different way of transmitting over the CB frequencies. There are several advantages to operating a CB radio in Sideband mode; 1) Instead of the traditional CB radio signal riding the atmospheric wave the signal emitted on SSB is a straight carrier wave. 2) The FCC allows 12 watts of transmit output power when SSB is enabled rather than 4 watts of transmit power allowed in regular CB mode. Therefore, due to enhanced power output and a straight carrier wave signal, greater distance is achieved when operating in Sideband mode. One draw-back is that in order to communicate with other users on Sideband, they must also have radios with Sideband built-in. An SSB CB Radio will still have 40 channels, however, there are 3 different ways to talk on them: upper, lower, and AM.  
• SWR - Some CB radios come with a built in SWR (Standing Wave Ratio) meter. This feature allows you to easily check the CB antenna and radio system (SWR) to ensure they are performing properly without purchasing a separate external SWR meter. This feature is extremely handy for trucker’s or users who change vehicles often or for people that frequently hit thier antennas with tree branches or other items. Check out our Help Center Article: What is SWR and Why is it So Important?
• Talkback - When a radio with a talk-back feature is enabled, it allows user to hear their own broadcast transmissions through the speaker. This comes in handy for setting microphone volume or adjusting the Mic Gain on the radio.
• Weather - WX. CB Radio with Weather.  Radios with this feature, when enabled have the ability to pick up NOAA weather broadcast frequencies. This feature provides instant weather information 24/7. Some of these radios even have an emergency alert feature that switches on automatically when NOAA broadcasts alerts are in the area of travel.

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