cb radio problems

[REBELARMY]

Recently purchased http://www.thunderpole.co.uk/off-roader_mirror.htm and got it fitted today on the rails on me Freelander 3 Door.

First turned it on and could hear some people talking but was very faint, this was just to test it worked etc.

Anyway got the swr metre out and proceeded to try and tune it, well followed all the instructons but the thing didnt even move :(

Whats have i done wrong?

[REBELARMY]

am i right to believe that the mount being on the roof rails are not a good ground plane/earth? tad confused lol

[Rex Hunt]

am i right to believe that the mount being on the roof rails are not a good ground plane/earth? tad confused lol

Are they plastic coated? anodised?

They need to be making good electrical contact back to the chassis.

See thread

cb radio questions

on here

Rex

[REBELARMY]

the rails are black metal thats the best can describe it lol so im guessing trhere anodised?

[REBELARMY]

http://www.desperateseller.co.uk/DespSellPhotos/667790703600.jpg

thats the rails the aerial is mounted on, if there no good how do i make a earth from them to the chassis? i.e what part of the mount do i connet the wire too?

BTW thats not my car just the best pic i could find to show the rails.

[REBELARMY]

ok we have wired a wire from the bottom of the mirror mount to a part of the chassis in the car.

This has helped as i can actually hear people talking and mmm singing lol

But when i plug in the swr metre i get nothing, tried 2 swr metre's same thing, once again the needle on the metres is in the black dont even move, well unless i shake it lol

Any ideas?

[REBELARMY]

Ok heres some pics, first one the antenna, then the wires coming into the car (earth and antenna wire) and third and final pic is where ive got the cb set up :)

[educationalist]

Sounds as though this could be a co-axial lead problem with the lead not making a good contact between the Antenna and unit. Antennas transform radio frequency based electrical currents into electromagnetic waves and the power of these signals rely in the end on your coax cable. Try attaching a peice of wire temporary to the antenna holder and a good known earth, if there is no difference in signal strength it could be your co-ax.
Also if your aerial has a way of moving the aerial shaft up and down from its base holder usually with a grub screw, try lengthening or shorenting the antenna known as triming.

[Rex Hunt]

Connect the SWR meter in line,
make sure it is the right way round.
Tx goes towards the radio,
Load or Ant connects to the aerial socket. BUT disconnect this side for now!
If your radio has a low/high power setting....set it to low for this next test.
Unscrew the aerial from the mount, leaving the coax connected, one end to the swr meter and hence to the radio.....the other end is still conected to the now aerial-less mounting.
BRIEFLY key the microphone and watch the swr needle for movement.(couple of seconds should be more than ample for this test!)
The meter should now give a high reading as you have a 'mismatch'.
If you have still not got a reading...you will need to check the connections/coax from the radio to the swr meter.
Now repeat the above you want a reading on that meter!

If the reading is high, we are making progress!

connect the coax from the antenna mount to the swr meter.

repeat the above short test. What happened.

high reading? Good reconnect aerial to mount and check swr meter reading again.....this should with a bit of luck be lower than the reading that you just had with no antenna. If the reading was less than 2:1 rejoice turn the high/low back to high,and go singing towards the pub as the radio is now usable!
In an ideal world you want to get as near as possible to a 1.2:1 for a good set up. But 2:1 is not too likely to cause any aggro.

When checking coax disconnect both ends from the sockets.
Use a multimeter set on the ohms or resistance range.
Check from the plug centre pin at one end to the centre pin at the other.......you should have a very low reading.......about 0.01ohms.
If this reading is high......one of the centre wires is adrift from the centre pins at one end or 'tother and needs sorting before we go any further!

Now do the same with both the outer shells of the plugs i.e. outer to outer should be low resistance.....with the same conclusions as above!

Next check....we are going to connect one outer to the meter and one inner to the meter................we are now looking for a high resistance, you will probably have to change the meter range to Megohms to get a reading!
IF you get a low reading.....gloom decends upon us and we put poff going to the pub until tomorrow!
The low reading (inner to outer) means trhat we have a 'short circuit' in one of the plugs! Don't ask me which one 'cos I can't tell you.....but you can almost guarantee that whichever end you check first.....the fault will be at the other end!

Connecting all back up....wth the aerial connected we are looking for low resistance readings from centre pin of the radio plug to the whip antenna.
we need a low reading from the outer shell of the radio coax plug TO THE VEHICLE CHASSIS EARTH via the mount. (if this is high then having done all the above.....you need to double check the bonding of the aerial mount to the car body.

Hope this tome is of more help than hindrance!

Good luck
73

Rex

[REBELARMY]

im afraid i lost the manual for the radio and dont know how to change it from LO to HI :(

also i dont have access to a multimetre and have already spent £84 on auto electrician bills lol

But i will off course try and give what youve said a try thank you :)

[Rex Hunt]

Have a look around your local area for a house with extra aerials,
The occupant is probably the nearest radio ham, smile sweetly approaching the door with a pack of Carlsburg's greatest, and ask him, as 'an expert', if he can help you!

He may even be able to check your swr meter out.

If you were nearer to Norwich I would offer my services.

Hope you get it sorted.

Rex

[REBELARMY]

indeed :) if all else fails when i test it again tomorrow im gonna take the hour's drive up to thunderpole in Northampton next week.

Cheers for all ya help will report back tomorrow

[REBELARMY]

ok tried what ya said Rex and nothing :( but decided to change the wires and guess what? ITS WORKS :)

was all down to dodgy wires so now its working. At the mo only got a range of 1 mile which seems a bit poor seeing as when testing it was on fields, my mate who i was testing with it has the same range but different radio!

Any ideas to boost the range?

[Rex Hunt]

Apart from the fact that it works.....Good!
Have you checked the swr?
Your transmitter should legally be putting out a maximum 4 Watts. With a good matching aerial (low swr) most of this will go out into 'the ether'.
The higher the swr reading, the more power that is being 'reflected' by the mismatched aerial. This relected power is not carrying your valuable signal to wherever it is intended.......but is feeding it back towards the power amplifier stages of your transmitter.
Result
1) poor comms
2) possibly 'piff paff puff' the smoke escapes from its little black box leaving an acrid smell and a hole in the pocket when you buy a replacement!

First stage now then is ti check the swr and make sure it is low.
Second.....make sure the radio is not set to 'low' power.(often a switch hidden underneath or round the back , sneaky these oriental types!)

And before anyone asks....NO you cannot put the smoke back into the box!
Once it is out....it is out!

Rex

[REBELARMY]

its a Team MC-8 and ive no idea how to change it from LO to HI looked in the manual dont say yet i know its there

and did the swr i got:
2.0 on channel 20
1.5 on channnel 1
2.1 on channel 40

that bad or good?

[timbott]

and did the swr i got:
2.0 on channel 20
1.5 on channnel 1
2.1 on channel 40

that bad or good?

Not bad, you shouldn't be chasing after your smoke with those readings:D Remember the 3 L's, if you have Low swr on the Low channels the aerial needs Lengthening. A bit of an over simplification of the art of aerial tuning maybe but handy for CB stuff and at least it gives you a clue which way to adjust the aerial for best SWR:)

cheers, Tim

[Rex Hunt]

Near enough to get away with it Rebel..........personally I would like to see it lowest about Channel 20 but I guess I am a bit fussy when it comes to radio.

Sounds like you are in business.

73 and good dx!

Rex

[REBELARMY]

now im worried lol gonna try and get it a tad lower, going up to thunderpole next week hopefully see if they can do anything :)

[uk_guy_1971]

hi REBELARMY & hi all,

this is becoming a bit of a proplem when our new motors don`t have any kind of guttering so useing a gutter mount is out of the question,

i would personaly think about other solutions like hatchback mounts also side mounts but hatchback mounts are good if your back door of your motor lifts upwards then maybe a hatchback mount would be good to use but here are other mounts i would like to share with you all,

http://www.thunderpole.co.uk/cb_radio_hatch+boot_mounts.htm

kind regards,

stuart.

[uk_guy_1971]

and i have also found this link with more mounts maybe looking through these might give you some more options and also other people and good luck with it all buddy and all the best,

http://www.thunderpole.co.uk/cb_radio_fixed_body_mounts.htm

[REBELARMY]

sorry didnt update this lol

anyway in the end i got it fitted to the roof rails and fed a earth down the hardtops rubber seals into the car and onto the chassis.

Now works like a dream and i even hit up to 6 miles the other day ofc its was very clear and sunny

[jcat4short]

hi all.bring back the days of am cb.you could even talk to america on 4 watts if you were lucky.i sat in a car park in tiverton devon and went in on the side of 2 american truckers in alabama.they were as suprised as i was.and if you went up to haytor as i often did with a little bit of heat you could chat to australia with np.then came 1981 and legality and all the muppets bought cb's.that spoit it a bit unfortunately.bring back the old days and auntie mary.:D:D:D
cheers maurice (aka outcast leader)

ps gonne get one fitted though handy green lanining.

[timbott]

hi all.bring back the days of am cb.you could even talk to america on 4 watts if you were lucky.i sat in a car park in tiverton devon and went in on the side of 2 american truckers in alabama.they were as suprised as i was.and if you went up to haytor as i often did with a little bit of heat you could chat to australia with np.then came 1981 and legality and all the muppets bought cb's.that spoit it a bit unfortunately.bring back the old days and auntie mary.:D:D:D
cheers maurice (aka outcast leader)

ps gonne get one fitted though handy green lanining.

Nothing to do with the fact that modulation was by varying the amplitide of the carrier wave (AM), but that they were really good active sunspot years and happened to coincide with the importation of loads of USA CB's into Britain. There is no reason why UK Frequency Modulated CB's shouldn't be capable of the same given similar excellent sunspot conditions and radios on the other side of the pond being UK spec:)

To be honest 11 metres is a silly wavelength for CB, which is intended for local communication. Around 2 metres/150MHz would be far more sensible really:rolleyes:

cheers, Tim

[Marc Lurie]

To be honest 11 metres is a silly wavelength for CB, which is intended for local communication.

I quite agree. Also, vehicle antennas at that frequency are inherently inefficient, and hand held units are not feasible.

Tim, theoretically FM would actually be better than AM for DX work due to the integrity of the FM modulation being less affected by "tumbling" in the ionosphere, where the polarity of the radiated signal starts to scatter and becomes unstable (which is the reason why horizontally polarised antennas can talk to vertically polarised antennas, but only after one ionoshpheric hop).

I used to do a fair amount of DX through the 10m repeater system in the US during the last solar maximum.

At the moment, solar activity is the lowest I've ever seen. It's practically dead on HF.