 | Home > Expedition & Overland > Fitting/grounding a cb radio in a 2004 Defender |
 
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| Adam17 Member Since: 15 May 2018 Location: Within Bedfordshire Posts: 1193   
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Hi all.
I have just got myself a midland 48 plus cb radio for my defender... (all the gear and no idea) Im ok to put it together & fit it... But my question is... Where can i ground the aerial cable? Without running it all the way to the chassis. As the roof and doors etc are aluminium it wont ground (the salesman said) The chap said that it needs to go back to the steel chassis. How ever, if i can find a point on the truck that feeds back to the chassis for example a door hinge (he said) then i wouldnt need to run the ground cable 'all the way' to the chassis. I got a gutter mount with it, so will be fitting the aerial up top. Whats closest to ground the aerial on? I go fit front or back i think, so which ever has the grounding point closest. Anyinfo welcomed. Thanks in advanced Kind kind kind regards The one who knows nothing but very willing to learn... Adam Regards Adam Loving The Duchess The Defender 110 TD5 XS My Defender story - http://www.defender2.net/forum/topic64005.html |
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31st Jul 2018 2:25pm |
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| gilarion Member Since: 05 Dec 2013 Location: Wales Posts: 5110  
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I have used a CB with an aerial gutter mount for years and never needed to ground the aerial just make sure where you mount the adapter is clean of paint etc.
If its any help with fitting all CB radios come with only 4 watts of power, so you'll need to get your antenna system working as efficiently as possible to maximize your radio's transmission and reception. If you do not receive a signal then use the SWR (standing wave ratio) meter to obtain the best trim. A poor performing antenna system significantly reduces (transmit & receive) range and can damage the transceiver. you trim by either releasing the grub screw on the aerial and move it up or down in its holder, if you do not have this type of aerial then you will have to trim by cutting off a very small portion (repeat: about 1/4th inch) of the tip at a time. Make smaller adjustments on shorter antennas. The shorter the antenna, the more sensitive it is to adjustments. For example, removing two wire turns on a 4-foot antenna might move the SWR by 0.3; the same amount removed from a 2-foot antenna may move the SWR by 1.0. If any adjustments are needed, they should be made in small increments. Re-check after each adjustment. Be sure to have all the components on the antenna when testing, including the tip/cap if there is one. Either way, these are the instructions for using an SWR meter 1. Turn your CB off and disconnect the antenna coax cable from the back of your radio. 2. Connect the end of your antenna coax to the SWR meter where it indicates "antenna" or "ANT". The connector inputs could be on the back and the labels on the front of the meter. 3. Connect the short coax jumper cable coming from the transmitter position on the SWR meter to the back of the CB where you took off the coax cable in step 1. 4. Close the hood and doors on your vehicle, and make sure there are no people or other large vehicles around the vehicle area. 5. Turn on the CB. 6. Set the CB to channel 40. 7. Set the SWR meter to the FWD (forward) position. 8. Key the microphone by depressing the talk button and turn knob until the SWR meter indicates the "set" position. Unkey the microphone by letting up on the talk button. 9. Flip the SWR meter to the "REF" (reflect) position. 10. Key the microphone and look at the SWR reading on the SWR meter for channel 40. Take note of that reading. 11. Repeat steps 6 through 10, this time on channel 1. 12. The lower the reading, the better your CB radio will perform. The goal is to set the antenna to the lowest SWR readings possible, evenly across the 40 channels- for example, the reading on channel 1 and 40 at the same at 1.5. By having the SWR readings match on channel 1 and 40, your radio will perform well on any of the channels within the 40 channel bandwidth. If they do not match, adjusting the antenna is advised. 13. IMPORTANT: If the meter reading is in the red zone, indicating HIGH SWR readings, DO NOT operate the CB. You could potentially damage your radio. A good tip If you have bought what is referred to as a "pre-tuned" aerial they typically use 18 feet of coax, so I recommend that you buy 18 feet of coax, even if you don't think you need that much. This just means that you will likely have less adjusting to do when you tune your antenna. And remember even if you bought a pre-tuned aerial this was not tuned to YOUR vehicle which is why you still need to tune your antenna. The ideal range! If your SWR is under 1.5 For those who like Welsh Mountains and narrow boats have a look at my videos and photos at.. http://www.youtube.com/user/conwy1 |
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31st Jul 2018 2:49pm |
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| Greyman110 Member Since: 29 Sep 2017 Location: London Posts: 327 
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You could probably use an artificial ground plane
http://www.4x4cb.com/public/item.cfm?itemID=972[/b] |
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31st Jul 2018 3:15pm |
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| Adam17 Member Since: 15 May 2018 Location: Within Bedfordshire Posts: 1193
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Thanks Gilarian. Very helpful.
The few channels i tried on i was gettimg just over 1.5, perhaps when i have a touch more time ill go over it again and recheck all the channels. Thanks again. Regards Adam Loving The Duchess The Defender 110 TD5 XS My Defender story - http://www.defender2.net/forum/topic64005.html |
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31st Jul 2018 5:18pm |
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| gilarion Member Since: 05 Dec 2013 Location: Wales Posts: 5110
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Usually, if you are getting a reading of 1.5 on channel 40 and receive the same 1.5 reading on the channel 1 you should find the readings are pretty constant on all the channels, you may get a slight difference on one or two channels but if the difference is very minor do not worry, I know this sounds daft but even a large truck going past when you are tuning can make a difference to the reading between channels. For those who like Welsh Mountains and narrow boats have a look at my videos and photos at..
http://www.youtube.com/user/conwy1 |
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31st Jul 2018 5:39pm |
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| SonicFields Member Since: 11 Jul 2017 Location: Somewhere Else Posts: 124 |
GREENI Now you're talking 1970/80........AM SSB CB with a 100W 'burner' used to enable mobile to mobile contact from UK to South America.
 CB was killed off by legislation and the introduction of FM rigs.
If you're having problems getting the SWR down to a safe level for the transmitter output, then try installing a small composite ATU/SWR/Power meter. We wouldn't think of running amateur radio transceivers without one, (modern amateur radio transceivers often have them built in) as apart from providing a match for the antenna impedance, they also provide a good visual safety check, as water ingress, corrosion, vibration causing loose connections etc. can drastically change the SWR, and many of the modern CB rigs do not have robust output protection against even the smallest of mismatches. And yes, I'm a reformed 1970s CBer, now with a Class 'A' Amateur Radio License  |
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31st Jul 2018 9:01pm |
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| Adam17 Member Since: 15 May 2018 Location: Within Bedfordshire Posts: 1193
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Hello again..
So i had another play, checked over multiple channels and am getting a reading now just under 1.5, so am happy now. Just doesnt seem to be anyone local enough to me to check with... Perhaps tomorrow after work ill drive to dunstable downs (highest part of Dunstable on some hills) and near a motorway so may get to talk with someone... At the moment i am surrounded by houses, so unlikely to get anyone let alone there is even someone else here using a cb radio... Haha. Ps is there a way i can boost my signal to get more distance? Thanks guys. Regards Adam Loving The Duchess The Defender 110 TD5 XS My Defender story - http://www.defender2.net/forum/topic64005.html |
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31st Jul 2018 9:49pm |
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| GREENI Member Since: 22 Aug 2010 Location: staffs Posts: 10381
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You can boost your signal, but you can't boost your receive, without bigger antennas etc. Leave as is for now, do you have a local off-road club? Ask someone get out on the CB!
I never went the full Amateur licence route, I did decide to start but my nearest club was full of 'undesirables' and a bit depressing. I stuck to 11m and SWL the rest of the bands, though I find the whole pile up for one guy and contest stuff a bit boring anyway. I do have a brand new yagi in my garage still. |
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1st Aug 2018 6:13am |
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| Adam17 Member Since: 15 May 2018 Location: Within Bedfordshire Posts: 1193
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I think devils pit is pretty close to me and thats full of offroaders, but i dont know of any clubs, ill have to scout the net today and find out.
Thanks for the info.. Ps whats this 11m and swl you speak of?  And whats a yagi? 
Thanks again. Regards Adam Loving The Duchess The Defender 110 TD5 XS My Defender story - http://www.defender2.net/forum/topic64005.html |
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1st Aug 2018 7:36am |
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| L110CDL Member Since: 31 Oct 2015 Location: Devon Posts: 10742
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Thanks for the memories GREENI, cant beat the old AM days
1996 Golf Blue 300Tdi 110 Pick up.
Keeper. Clayton. |
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2nd Aug 2018 9:23pm |
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| GREENI Member Since: 22 Aug 2010 Location: staffs Posts: 10381
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Sorry, for my hijack, 11metres is a 'pirate' frequency, around 26-27mhz A yagi is an antenna that's directional, think of a TV antenna and how it points a certain way to get reception. Some people put loads on their properties for different bands (frequencies) and they have motors on the mast to turn them around. Or have certain antennas pointing to certain countries.  Click image to enlarge SWL is short wave listener. Radio is very complicated, interesting and often labelled 'nerdy'. |
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2nd Aug 2018 10:46pm |
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| custom90 Member Since: 21 Jan 2010 Location: South West, England. Posts: 20348
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Masts / very long aerials are very good Lightning conductors too so worth bearing that in mind or anything else Electrical overhead for that matter.
$W33T $0U7H3RN $UG4R
🇬🇧🏴🏴🏴🇮🇪🇺🇸⛽️🛢️⚙️🧰💪 |
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2nd Aug 2018 10:51pm |
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| Adam17 Member Since: 15 May 2018 Location: Within Bedfordshire Posts: 1193
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Wow, thanks for the info. Regards
Adam Loving The Duchess The Defender 110 TD5 XS My Defender story - http://www.defender2.net/forum/topic64005.html |
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3rd Aug 2018 3:38pm |
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| gilarion Member Since: 05 Dec 2013 Location: Wales Posts: 5110
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For those who like Welsh Mountains and narrow boats have a look at my videos and photos at..
http://www.youtube.com/user/conwy1 |
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3rd Aug 2018 5:02pm |
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