Maroondestroyer

Maroondestroyer

Active Member
just fitted a C.B. today, it has a central loaded antenna. C.B. turns on, all buttons work. Coax plugged in and wired up to antenna. Auto squelch.
When I click search function, it literally picks nothing up. So I drove around a five mile radius to see if it’d pick anything up (only thing I picked up, was a cold, because I forgot my coat). Is it that quiet now on the C.B., that there is a good chance that nobody was broadcasting at the time. Or does it sound like an issue? I have read to check antenna earth to body and ‘link an extra wire to a close by earth on a light or something. Does this make sense to anyone ‘in the know’? Obviously no response when I tried a comms check.

Thanks.
 
Thanks. I did read something along those lines, but that is as simple as it gets.

I thought a ‘tuned antenna’ may work 7 mile but an un-tuned one about 3. This says it will dramatically affect the transceiver if it’s wrong. Will try tuning. Thanks.
 
Maroondestroyer said:
Thanks. I did read something along those lines, but that is as simple as it gets.

I thought a ‘tuned antenna’ may work 7 mile but an un-tuned one about 3. This says it will dramatically affect the transceiver if it’s wrong. Will try tuning. Thanks.
Click to expand...
You really need to tune it first before you think it's broke ;)
 
As the others have said, check the tuning of the aerial. It not only shows you how the transmitter is behaving, but if the aerial works properly on transmit then it will work properly on receive.
But to be honest, yes the CB frequencies are very quiet these days. Often CB is only used by arrangement such as when out laning in a group.
 
brian47 said:
As the others have said, check the tuning of the aerial. It not only shows you how the transmitter is behaving, but if the aerial works properly on transmit then it will work properly on receive.
But to be honest, yes the CB frequencies are very quiet these days. Often CB is only used by arrangement such as when out laning in a group.
Click to expand...

SWR has nothing to do with recpetion it is only relevant for transmission!

If your antenna is badly tuned it will still recieve exactly the same (providing it is the correct size antenna for the band of course)

SWR (Standing Wave Ratio) hence it is expressed as a ratio.
Standing-wave ratio (SWR) is a mathematical expression of the non-uniformity of an electromagnetic field on a transmission line. The SWR can also be defined as the ratio of the maximum RF to the minimum RF current on the line.

OK so now in plain english!! ( or how It was explained to me many moons ago)
On the UK CB 11m band / 27 Mhz when transmitting you should be reading less than 1 to 1.5 accross all channels. You will have some deviation between your highest and lowest channels, that is normal. In simple terms its the amount of transmitted signal that does not 'leave the antenna'.
By adjusting (AKA tuning) the length of the antenna you adjusting the impedance which iin turn affects the amount of 'reflected' power coming back down the antenna.

Reception problems are normally associated with poor ground (AKA ground plane) or bad connection at antenna end or your PL plug (CB end)

An easy way to test your antenna's ground is check continuity between the CB antenna mount and your vehicle ground, because if the antenna mount is well grounded, so is your antenna.

Either that or your auto squelch is set wrong or is malfunctioning. (hate auto squlech!!) need to hear the hiss to hear the deviation,
So if you can turn it off and hear a steady hiss with absolutly no change ( listen very carefully) in tone your antenna is not connected! remove the cable and check again if the hiss does not change as you plug in the antenna its a connection problem ( perfectly safe to do this just do not try to trasnmit without your aantenna plugged in your will fry your output trannys!

Or ( and most likley ) no one is out there!!,

Go to top of a large hill, (one where you can see down accross the lanscape) try recieving from there.

PS you should not need to run an extra earth wire, but if you do make a fresh earth point, do not use one that is for somthing else........ not good!
 
Last edited:
KISSMYAURA said:
SWR has nothing to do with recpetion it is only relevant for transmission!

If your antenna is badly tuned it will still recieve exactly the same (providing it is the correct size antenna for the band of course)

SWR (Standing Wave Ratio) hence it is expressed as a ratio.
Standing-wave ratio (SWR) is a mathematical expression of the non-uniformity of an electromagnetic field on a transmission line. The SWR can also be defined as the ratio of the maximum RF to the minimum RF current on the line.

OK so now in plain english!! ( or how It was explained to me many moons ago)
On the UK CB 11m band / 27 Mhz when transmitting you should be reading less than 1 to 1.5 accross all channels. You will have some deviation between your highest and lowest channels, that is normal. In simple terms its the amount of transmitted signal that does not 'leave the antenna'.
By adjusting (AKA tuning) the length of the antenna you adjusting the impedance which iin turn affects the amount of 'reflected' power coming back down the antenna.

Reception problems are normally associated with poor ground (AKA ground plane) or bad connection at antenna end or your PL plug (CB end)

An easy way to test your antenna's ground is check continuity between the CB antenna mount and your vehicle ground, because if the antenna mount is well grounded, so is your antenna.

Either that or your auto squelch is set wrong or is malfunctioning. (hate auto squlech!!) need to hear the hiss to hear the deviation,
So if you can turn it off and hear a steady hiss with absolutly no change ( listen very carefully) in tone your antenna is not connected! remove the cable and check again if the hiss does not change as you plug in the antenna its a connection problem ( perfectly safe to do this just do not try to trasnmit without your aantenna plugged in your will fry your output trannys!

Or ( and most likley ) no one is out there!!,

Go to top of a large hill, (one where you can see down accross the lanscape) try recieving from there.

PS you should not need to run an extra earth wire, but if you do make a fresh earth point, do not use one that is for somthing else........ not good!
Click to expand...

As an ex-radio engineer of about 40 years, I dispute some of that.
If there is a fault on the aerial line such as an open or short circuit, both of which can very easily occur in a new installation then a VSWR check will show up as a fault in almost all cases. If such a fault exists on the line then the installation will neither transmit nor receive. I say "almost all cases" there because I have come across faulty aerial feeders which returned a perfect 1:1 VSWR but the station failed to work, transmit or receive. Those times the feeder was faulty at a critical distance from the transmitter. VSWR works in most cases but it isn't the "be all and end all" of RF transmission lines.
Once the condition of the transmission line and the radiating element has been established as tuned for the transmitter then it will work for the receiver.
If however the radiating element is out of tune, often stated as a VSWR worse than 3:1 then the transmitter probably won't work as expected but the receiver probably will work. A VSWR above about 3:1 could in some cases result in the transmitter shutting down as a safety feature or in the worst case, the high reflected power could result in a failure of the final stage, more likely to happen in a semiconductor power amplifier than a valve stage.

On the subject of an earth hard wired to the base of the aerial, that would sometimes depend on the type of aerial but not always. Think about how a mag-mount works. There is no body connection at the base of the aerial but it still works as it should, even if the radiating element is a single quarter wave in length. It does it by capacitive coupling and a system of parasitic mirroring of the radiating element on the ground plane.
 
SWR (antenna system matching) does affect reception, in the case of a CB in your Landy it will have minimal impact on near by signals. The truth of the matter is that hardly anyone uses CB anymore and that the few that do tend to have community contacts on particular channels. Many folk now ignore the legalised EU and UK channels and use the 27.555 MHz calling channel which your rig is inlikely to be fitted with.

What you need is a friend to talk to, arrange something near by... or just accept the CB as another useless thing hanging off a Land Rover, like ladders that don’t go anywhere, running boards that collect rusty mud and snorkels for cars that will never wade.
 
Last edited:
Magicgrotto said:
Also is it a 40 channel Or a 80 channel CB good buddy ?
Click to expand...
images

whats your 10,10 good buddy
 
Dartmoor Navigator said:
SWR (antenna system matching) does affect reception, in the case of a CB in your Landy it will have minimal impact on near by signals. The truth of the matter is that hardly anyone uses CB anymore and that the few that do tend to have community contacts on particular channels. Many folk now ignore the legalised EU and UK channels and use the 27.555 MHz calling channel which your rig is inlikely to be fitted with.

What you need is a friend to talk to, arrange something near by... or just accept the CB as another useless thing hanging off a Land Rover, like ladders that don’t go anywhere, running boards that collect rusty mud and snorkels for cars that will never wade.
Click to expand...
if your coax cable is to short or rolled into a coil you can have serious issue
 
Thor1950 said:
if your coax cable is to short or rolled into a coil you can have serious issue
Click to expand...

It is about matching the impedance of the rig (50 ohms) to the final impedance of the antenna system (including the coax). Coaxial cable creates resistance, capacitance and inductance and consequently the length of it and how it is laid affects this ‘impedance’. It will be relatively unrelated to the OPs problem as nobody really uses CB anymore and that is the most likely reason he can’t hear anything... in its hay day (1980s) he could have shoved a bent coat hanger in the socket and he would have picked up transmissions.

To the OP - for CB related guff try a forum called transmission1.net - there might be some folk on there near to you.
 
CBs have gone quiet round here. But you should be able to pick someone chatting.
As said above make sure Conections,swr,Ariel etc are all correct.

Now for the naughty bit...
If you get bored get a BIG burner & arial to suit. Used to make rally recovery days fun chatting with weirdos.
 
There's hardly any fecka on these days , just the odd trucker ! Got a cobra 148 with mid band and even Chanel 19 is empty at the mo in the north east ! Just flicked mine on. I've got a fook off
thunder pole in the back garden too.
You always had a 19 to Roger or Mike Check every 5 mins!

Turn your squelch off for now! As mr Aura said. It will make a racket! But you will here all the faint signals !!

19 to Roger!!!!!!!!!
 
Rodger Rodger @Weldy

80 channels of silence.
(Bit like the TV some days)

Wait for the sun to warm up & green lanes to open,normally get some nutters on as they are stuck and no phone signal.
 
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