There are some CB's with very few features, and some with a huge number of them!
This is what they do...
Squelch This allows you to cut the background hiss heard between transmissions.
It sets a signal strength threshold below which the sound is cut.
It's a rotary control, and the further clockwise the squelch is turned, the stronger a signal needs to be to break through and be heard.
The trick is to set the squelch so it's high enough to stop the background noise (which is usually at a low signal level) but not have it set too high so that its cuts out the people you want to hear (hopefully they are at a higher signal level).
Every CB has a "normal" quelch control that you adjust manually, but some also have variations on this which are designed to do the work for you or at least help you somehwat :
Automatic Squelch This can be a useful feature but be wary if you are wanting to hear people who are at low or fluctuating signal levels - the automatic squelch is usually set a bit higher than would normally "squelch out" the background noise - this is so that theres little chance of hearing any background noise but this is sometimes at the expense of hearing weak signals.
Auto Q Squelch A function on the Maycom EM27 that allows a limited amount of sound out when the signal is under the squelch. This can be handy as normally if someone is below the squelch threshold you will not hear them at all, whereas with Auto Q, you can hear a bit - enough for you to perhaps recognise your pal's voice and be able to readjust the squelch while still keeping the annoying background noise to a minimum.
ESP Squelch A feature on many Midland sets which actually works very similarly to the Auto Q facility described above. Sound is muted to about 50% and treble is reduced when listening to below-squelch-threshold signals, to further reduce the nasty background noise you might hear otherwise.
Signal meter The signal meter gives an indication of the strength you are receiving signals at.
When transmitting, the meter will usually go up to the top to give an indication of power output, although it's rare for this to acurately reflect the output power being transmitted - it's probably fairer to think of it as a "transmit indicator" rather than a power meter!
In the "old days" of CB, every cb had a signal meter, even the very cheapest, but nowadays it's quite common for the more basic sets to not have one.
Most CB's that have a signal meter show it on their LCD displays as a "graph" - the more segments that appear, the stronger the signal is... there are still a couple of sets (namely the Midland 248 Excel and the President Walker) that use a needle moving up & down a scale - this is how the older sets used to do it, and is generally considered better as there may only be 9-12 segments to the LCD graph types, but the needle types can show differences down to a "needles width"!
Having a signal meter does have a couple of advantages :
- You can visibly see the signal level of any background noise there is on the band so you can find a clear channel.
- Being able to give someone a signal report is also very useful and can be a good conversation starter on the calling channel.
Mic Gain & RF Gain These are rotary controls found on some sets... i've got to be honest and say that i do actually wonder why they are included on CB' nowadays, as their potential to be used incorrectly and cause problems far outweighs their slight advantages.
It's important to remember that in normal use the controls should be turned up fully clockwise for best performance
Microphone Gain Is basically a volume control for your transmitted audio, so if you fancy transmitting silence and annoying people or getting ignored, then turn this down... otherwise TURN IT UP!
Having said this, if you have a lot of background noise in your vdub, and this is being transmitted - it may help to turn the Mic Gain down a little, and speak closer to the mic.
RF Gain Adjusts the receivers' sensitivity - the idea being that very strong signals from someone right next to you don't overload the receiver or if you are getting interference from a nearby cb user on another channel (an effect called "bleedover"), then you can turn the RF gain down to lessen the breakthrough, however with the fewer users on cb nowadays and the better filtering of modern cb sets which largely avoids bleedover anyway, this facility is of limited use. If you fancy not being able to hear anyone, then turn this down... otherwise TURN IT UP!
Last Channel Recall (LCR) Pressing LCR will normally take you back to the last channel you transmitted on - ideal if you've had the rig on scan as you are driving along and last transmitted on the mobile calling channel and wish to get back there.
If a group of you are having a conversation on one channel, you can "flick" around the other channels & get back to where you were with one button push.
Some sets have this feature set up slightly differently as they will count the last channel you spent more than a minute on as the channel to take you to when you press LCR.
If this is important to you, get in touch and we can explain how the different sets do it.
Dual Watch (DW) This function allows you to set a priority channel which the rig will check once every three seconds or so, as you listen to another channel or move around the band.
This function only works with the squelch set to quieten background noise - the rig will switch over to your priority channel when a signal strong enough to open the squelch appears.
As with many of the "digital" facilities on modern CB sets, the different manufacturers have implemented the various facilities slightly differently. Get in touch if you wish to know how a particular sets' DW works.
Scan Like LCR, scan performs slightly differently depending on the radio make/model.
The idea is to set the squelch to quieten background noise, press Scan and the radio will search through the channels looking for a busy one.
When one is found, the scan will stop for a short while, (a couple of seconds), then resume scanning.
Many Midland sets will do a "sweep" scan of all forty channels of the band you are on and then stop, whereas some sets like the Maycom EM-27 will scan continuously until stopped manually.
Other differences are that most sets will stop scanning as soon as a channel change control is used (either on the front of the set or on the microphone), but the Maycom will allow you to change the direction of the scan, up or down via the channel change.
Channel change/Band change buttons on the microphone Having channel and band change buttons on the microphone can be very useful as you can perform these functions while driving, without having to touch the set itself.
The only disadvantage is that you risk changing channel when you don't want to, especially if you've grabbed the mic in a hurry.
Nearly all the CB's available now have the buttons on the top of the mic, so this is not so much of a problem, and quite a few now feature a LOCK button, to prevent any accidental channel changes.
Public Address facility (PA) This can be a very handy (and fun) facility - although there are currently only a few sets that have it.
You can mount a water resistant speaker under your bonnet or around the vehicle, and switching over to PA allows you to broadcast your voice through this speaker at high volume!
Shout at your mates / passers by / the idiot who's just pulled out in front of you, or perfect your "police siren" whistle... all good fun!
Channel 9/19 button This can be pretty handy... the idea is that it gives you instant access to either channel 9 (the emergency channel) or channel 19 (the calling channel) without having to use the normal channel change control, and then having to use it again to get back to the channel you were on.
For example, imagine you're on channel 36 chatting to your mates but want to check channel 19 for a traffic report... press the CH9/19 button once and you're on channel 9, press it again and you're on channel 19, press it again and you're back on channel 36.
Programmable memories Some sets allow you to program your most commonly used channels into instant-access memory locations that can usually be brought up with one button push.