Homebase CB Radio - The Citizens Band - 27 MHz 11 Meters Open Channel Radio

HOMEBASE CITIZENS BAND RADIO

BigCat says: Don't hog the One Nine! - Channel 19 is not for general conversations.
Move off channel 19 a.s.a.p. & keep the calling channel clear for other breakers !

How to set up your Homebase CB Radio

Wouldn't it be great would it be to have a CB radio permanently available in your home? Yes, really great! It's really easy too.

In it's simplest form all you need is a CB radio, Power Supply and Antenna with suitable 50 Ohm coaxial aerial connecting cable:

.	Plus		Plus
Power Supply Unit		A CB Radio ("Rig")		CB Antenna

Additionally you will need a few extra small items - a suitable power connector, an "SWR" meter and a short PL259 to PL259 50 ohm "patch lead" and preferably a 'low pass' (TVI) filter. See SWR & Antennas & CB Accessories

When choosing a new CB rig be sure to visit one of the highly valued specialist CB retailers that can be found on the CB Links Page.

HOMEBASE CB RADIOS ("Rigs")

Mobile CB radios are compact and ideal for mounting in confined spaces in cars, vans and trucks. Mobile CB radios also run off a 12 volt DC power supply that is usually available in vehicles. For use at home manufacturers made special HomeBase CB radios that had built in mains transformers to enable them to work off standard 230 volt AC household mains power.

Homebase rigs had the same facilities and controls as mobile CB radios except they were often larger and had a built in mains transformer, however there are currently no homebase CB's in production. This no great matter since they were often quite expensive, maybe costing over £150, and exactly the same job can be done with a mobile CB transceiver connected to a special Power Supply Unit - for less money.

A good mid-range CB may cost between £65 and £80 and a Power Supply for £25 to £30. That's only £90 to £110 and much less than a dedicated homebase radio..

The choice of new CB radios is very large and prices vary from about £50 to well over £100. It is well worth bearing in mind that no matter what the price of a new radio they all have a transmitter power of 4 watts. 4 watts is the legal maximum, so an expensive rig will transmit no further than a cheaper one!

To gain greater range it is wise to spend more on a larger and better antenna than a more expensive radio. More expensive CB radios do tend to have more comprehensive facilities and are usually better finished with a higher build quality.

When buying a radio it is very important to ensure that it covers both to 40 UK (27/81) channels AND the 40 EU (CEPT) channels. That's essentially 80 channels. The latest CB radios are extremely clever and are specially programmed to be able to be set for use in individual European countries where different regulations apply - this takes account of differing channel sets, transmissions modes and output powers, this is called 'multi-region' capability, so look out for Multi-Region capable radios.

Look out for brands such as Midland Alan, President, Intek, Team, tti, and Danita for example. See our Links page.

There are always a number of CB radios on the second hand market, particularly the auction sites such as e-bay, but many of these have only half the number of channels that you need - namely the 40 UK channels. Personally I would NEVER buy a second hand CB radio - EVER! Many CB radio enthusiasts often like to make all sorts modifications to the internal electronic circuits, and you will never be sure that a second hand CB will be working properly.

Only the day before writing this page, I was talking on the CB to a breaker who proudly announced that he had just bought a second hand CB. He then connected it to his antenna and power supply and keyed the microphone. I heard him talk for about 20 seconds before his voice disappeared and the rig appeared to be permanently keyed up on the channel with no modulation. He then had to disconnect the CB and returned to the air with the original rig. Apparently some of the circuitry had been tampered with inside, so now he has the problem of trying to fix the problem himself or pay for a repair. That's just one of many examples so be warned!

CONTROLS & FACILITIES:

A CB radio needs only a minimal number of controls to be fully functional, although some rigs include many more. The basic and essential controls are On/Off, Volume, Channel Change, Band Change and Squelch. A basic CB radio will probably be more than adequate for most newcomers, though there's no reason why one should not choose a more complex radio, but bear in mind that it is more important to concentrate on buying the biggest and best antenna possible than the most complex radio.

The more expensive radios might include a number of other controls which may or may not be of particular importance to individual users. These may include adjustable microphone gain, adjustable RF gain, memories, channel scan, dual watch, last channel recall, noise limiter or processor, PA, key lock, frequency display, quick up & down buttons. See the table below for more details:

On/Off Vol: Switches radio on and off and adjusts audio volume

Band Change: Switches between UK and EU bands

Mic Gain: Adjusts to volume of the transmitted audio. If your transmitted audio is too high it will cause 'over-deviation' of the signal causing distortion which will make it difficult for other to understand what you are saying. This control allows you to make adjustments.

Memories: Some radios have several memories to store often used channels.

Channel Scan: Can be set to continually scan through all the channels until a transmission is found.

LCR: Last Channel Recall is used to return to the last channel transmitted on.

PA: Allows a "Public Address" function to be used through an external loudspeaker.

Key Lock: Allows keypad buttons to be locked so that channels cannot accidentally be changed.

Quick Up Down Buttons: Jumps 10 channels up or down at a time.

Channel Change: A rotary knob or up down buttons select channels 1 to 40

Squelch: A noise gate that cuts out the hiss & noise present when there is no signal. Adjustable for varying signal strengths - to receive weaker signals it needs to be set as low as possible, at the point when the noise and hiss just stops.

RF Gain: This control adjusts the amount of amplification in the receiver (RX) circuits. Normally set at maximum for best sensitivity, but can be reduced to prevent close by transmissions causing receiver overloading (noise and splatter).

Dual Watch (DW): Used to monitor two channels simultaneously.

Noise Limiter/Reduction: Can help reduce noise or increase intelligibility of weak signals - with varying degrees off success.

Frequency Display: Allows display to show the transmitted frequency in addition to, or instead of the channel number.

Mic Channel Change Buttons: Channel change buttons located on microphone for convenient channel changes.

Signal Meters

Most CB radios will also include a Signal Meter that will give an indication of the received signal strength - referred to in CB parlance as 'Poundage'. Bear in mind that not even the signal meters on the most expensive radios are accurate or properly calibrated, and can only give a visual representation of relative signal strengths. Most modern CB's have a signal meter in the form of an LED bar-graph (like a mobile phone) but others have a more traditional 'swinging needle' analogue meter that many CB operators prefer since it looks like rigs of old and can show infinite movements in signal strength.


LCD Bargraph S Meter	Analogue 'swinging needle' S Meter

Signal meters have scales marked S1 - S9. S1 being the weakest signal and S9 being strong signals. S9 represents a received signal of, (arguably), 50 microvolts. There are additional markings above S9, usually marked +30 on CB radios, which means a voltage of 30 decibels above 50 microvolts which is 1580 microvolts. Many S meters also double as a very rudimentary power meter to provide an indication of the power output when transmitting (TX).

See more about "S" Meters Here >

When choosing a new radio be sure to visit one of the highly valued specialist CB retailers that can be found on the CB Links Page.

POWER SUPPLY UNITS ("PSU" / "Power Pack")

Mobile CB radios are designed to run from around 13.2 volts, but anything between 12 and 14.5 volts is acceptable. Since it is necessary to use a mobile CB radio for use at home it will need to be supplied with the correct voltage. Special power supply units, designed for powering radio equipment from the 230 volt mains supply is readily available.

Never use a 12 volt car battery to power your CB radio! This is a very dangerous practice due to the hazardous and corrosive chemicals that are contained in car batteries and the risks of dangerous fumes being released. A car battery is definitely NOT something that you want in a home environment.

For a normal CB radio a power supply capable of supplying a current of 3 amps at 13.8 volts is ideal. These are widely available and relatively inexpensive.

If you think that you may want to power additional equipment and accessories in the future, then more expensive power supplies are available that are capable of providing greater current that may be necessary. For example 13.8 volt PSU's that are capable of providing 7 amps, 10 amps or 20 amps will also be perfect for this application.

The Power Supply shown in the photograph above is a Sharman's 10 amp unit. Shaman's is a well regarded brand name in this field and is a name to look out for.

HOME BASE CB ANTENNAS (Aerials / "Twigs")

The antenna really is the most important part of any CB station. Any extra investment should be directed to the antenna system rather than the radio. In the world of CB radio bigger really is better! The longer the antenna the better the reception will be and the further your signal will carry, however the length of any antenna must also be of an electrically correct length - tuned to be resonant at the frequency being used. In simplest terms, the idea is to get an antenna as near to the size of the wavelength of the radio wave that is possible. This will provide the best signals. However bear in mind that bigger antennas are heavier and also present a much greater wind loading so this should be borne in mind when choosing suitable mounting brackets. Also install the antenna as high as is safe and practical. Height above ground is everything. The base of the antenna really should be at a minimum of 20 feet (6 or 7 m) above the ground - more if possible as every extra foot of height counts. CB uses radio frequencies of around 27 MHz which have wavelengths of around 11 meters (300 divided by 27 = 11.1m) An antenna that is 11 meters long might be considered somewhat unwieldy. However the most basic and practical antenna is the "half wave dipole" and is also one of easiest to construct being made from a 1/4 wave top section and a 1/4 wave bottom section, which makes it just 5.5 meters long. The feed point, where the coaxial cable connects to the antenna, in in the centre. The dipole has 0dB (zero) gain and is also a reference antenna by which all other types of antenna are judged.	Sirio 827
The quarter wave ground-plane antenna is reasonably small; it has one vertical driven element that is 2.75 meters long, fed against 3 or four horizontal radial elements that form the ground plane. Like the dipole antenna, mentioned above, the quarter wave ground-plane also has zero gain, however the angle of radiation is higher than the dipole which might be beneficial for short skip conditions. The dipole, however, has a lower angle of radiation which will probably be more beneficial for local contacts. The height and size of a ground plane antenna may be further reduced by adding a base loading coil at the bottom of the vertical radiator which might make the antenna less than 2 meters tall - this is a "reduced quarter wave antenna". This would be at the expense of efficiency and the antenna would effectively have negative gain, but for local contacts this may still be perfectly acceptable. This type of antenna, at 1.5 meters long, was actually a legal requirement under the terms of the CB licence when citizens band radio was legalised in 1981. One of the most popular and cost-effective antennas used for 'Home Base' operation is the 1/2 wave "silver rod" antenna which is about 5.5 meters long - the same as a dipole - but the difference being that the feed point is at the base of the antenna rather than in the centre as is the case of the dipole. Because of this the end-fed 1/2 wave antenna has to have a matching coil fitted at its base to match the higher impedance of the end fed antenna to the 50 ohms impedance required by the radio. The 1/2 wave Silver Rod type antenna has 0dB gain compared to a dipole, usually expressed as 0dBd. It weighs about 2.5 kg with a wind resistance of about 156 N @ 150 km/h. The popular Solarcon A99 / Antron 99 antenna can be considered as a 1/2 wave end fed antenna, although its electrical arrangement is slightly different to a standard 1/2 wave silver rod. It is much more expensive than a silver rod, but has no significant gain over a dipole or the silver rod. However its real advantage is that it is made of fibreglass with the wire conductor contained within, making it very resilient to bad weather conditions. It is also extremely easy to assemble, making it ideal for constructing or dismantling in a hurry. A note about antenna gain figures > The next step up from a 1/2 wave Silver rod is the 5/8th wave. It's slightly longer than the 1/2 wave antenna at about 6.5 meters long and is therefore more effective. The gain being about 1 dBd (3.15 dBi). Weight is about 2.5 kg with wind loading of 188 N @ 150 km/h. The angle of radiation is also lower than the half wave 'silver rod' which would make it a better choice for long distance skip, though its large size must be taken into consideration. Larger still would be something like a 5/8th wave ground plane antenna such as the Sirio 827 which has 1.5 dBd gain (3.65 dBi) or the even larger 7/8th wave Sirio Vector 4000 which has 2.0 dBd gain (4.15 dBi). These are heavy and large antennas with substantial wind resistance; 6.0 kg / 264 N @ 150 km/h and 4.6 kg / 356 N @ 150 km/h respectively. There are many choices of antenna available for home base installations so check out a specialist CB retailer for the availability of all current models.	Silver Rod
Here are some examples of ground-plane and dipole antennas:


SIRIO Starduster 1/4λ ground plane Frequency range: tunable from 26.5 to 30 MHz Impedance: 50Ω unbalanced Gain: 0 dBd, 2.15 dBi Bandwidth @ SWR ≤ 2: ;≥ 2000 KHz @ 26.5 MHz SWR @ res. freq.: ≤ 1.5 Max. power: 1000 Watts (CW) continuous 3000 Watts (CW) short time Wind load / resistance: 75 N at 150 Km/h / 130 Km/h Wind surface: 0.07 m² Height (approx.): 5040 mm Weight (approx.): 1230 gr Radial length (approx.): 2690 mm Mounting mast: Ø 35-40 mm	SIRIO Signal Keeper Reduced - base loaded - 1/4 wave ground plane antenna Frequency range: 26-28 MHz Impedance: 50Ω unbalanced Gain: < 0 dBd, 2.15 dBi Bandwidth at S.W.R. 2:1: 850 KHz S.W.R. at res. freq.: ≤ 1.2:1 Max. power: 100 Watts (CW) continuous 300 Watts (CW) short time Wind load / resistance: 36 N at 150 Km/h / 130 Km/h Wind surface: 0.03 m² Height (approx.): 2370 mm Weight (approx.): 640 gr Radial length (approx.): 640 mm Mounting mast: Ø 35-40 mm	SIRIO SD 27 Dipole Frequency range: 26-28 MHz Impedance: 50Ω unbalanced Gain: 0 dBd, 2.15 dBi Bandwidth at S.W.R. 2:1: 3750 KHz S.W.R. at res. freq.: ≤ 1.1:1 Max. power: 1000 Watts (CW) continuous 3000 Watts (CW) short time Feed system / position: Gamma match / center Wind load / resistance: 80 N at 150 Km/h / 130 Km/h Wind surface: 0.07 m² Length (approx.): 5420 mm Weight (approx.): 2560 gr Mounting mast: Ø 35-50 mm

Mounting The Antenna

Apart from the antenna itself, the greatest influence on the effectiveness and efficiency of an antenna system is the height above ground level. The higher the better: The minimum height above ground level should be about 20 feet (6 to 7 metres). If possible get all or the greater proportion of the length of the antenna above the height of the roof-line since buildings will screen and reduce the signals from the antenna.

One of the most popular and easiest methods of mounting an antenna is onto a sturdy 1.5" or 2.0" aluminium pole with strong 1.6mm or 1.8mm walls, fixed to the side of the building or house with sturdy galvanised "T and K" brackets. These brackets need to be fixed to the wall with equally strong Rawplug anchors or Rawbolts.

Galvanised T & K brackets

Another method is to mount the antenna at the top of a 20 foot or 30 foot aluminium mast mounted in the garden, a few meters away from the building. A mast of this height would need to be made of 1.75" or 2.0" diameter aluminium masting with 1.6mm or 1.8mm walls and firmly guyed for safety.

The photograph on the right shows how a standard Silver Rod (this one sold by Thunderpole) is easily fixed to the top of an aluminium mast with U bolts.

Thunderpole 1/2 wave
'Silver Rod' antenna - an
effective, inexpensive
& popular CB antenna

Always observe the strictest safety precautions when working at height and when climbing ladders.

Cable and Plugs

Good quality 50 ohm coaxial cable should be used to connect the antenna to the radio. Higher quality cable has denser more effective braid screening which minimizes signal losses and reduces the possibility of interference being caused. The best quality RG58 C/U should be sufficient for cable lengths of up to 30 meters. RG58 C/U is 6mm thick and will need matching PL259 plugs with 6mm cable entry. The next step up is RG8 Mini which is higher quality and has lower loss. RG8 Mini is 7mm in diameter and will need matching PL259 plugs with 7mm cable entry. Another alternative is RG213 which is the highest quality, lowest loss but at 10mm diameter it is very inflexible and difficult to work with and will need matching PL259 plugs with 10mm cable entry. RG213 is probably overkill for this sort of work.

Well known CB expert Lou Franklin of CBC International recommends that coaxial cable should be cut in odd 1/4 wave (9 foot or 2.75 metre) lengths. e.g. if the distance from the antenna to the radio required an 11m length of cable, then the length of cable that you would actually use would be 2.75 X 5 = 13.75 metres.

It will be necessary to solder a PL259 plug onto each end of the cable and it is important to use good quality plugs and ensure that the solder joints are of good quality.