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CB radios and scanners

Discussion in 'VA/DC/MD- Capital Land Cruiser Club' started by topherbecker, Mar 6, 2011.

  1. topherbecker

    topherbecker

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    Can the CB be mounted in a tuffy? or does that mess with it's ability to transmit?
     
  2. Devilmans Hand

    Devilmans Hand TLCA #19517

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    Ed, what do you think of the cobra 19dx IV? seems to be some easy mods available too. It seems to have everything that i'd need in a cb, if it works. Run it with an external speaker and PA system when needed. Maybe the uniden 520xl too.Uniden Pro 520 XL CB Radio Information

    Some other 40 owners have a lot of issues with electrical interference. Is there a somewhat simple way to isolate/shield the receiver better than the stock case?
    in the electronics secion of the forum they've just run ground straps from the alternator, exhaust, and used different kinds of spark plugs. My ignition coil had a rf absorber or something attached to it too, before it broke anyway. What other necessary mods to the vehicle are fj40 owners looking at?

    I'm thinking about mounting a fiberglass antenna for the woods and TLCA events, then a 102"whip for everywhere else. I'd then switch between the two as necessary, and not run them as dual antanea. Thinking both mounted in the rear of the 40 somewhere. maybe one off the spare tire and the other off a bracket from the rear ambulance door top right hinge.

    I plan to get into amateur radio soon too. I'd rather save my money for some of that decent gear later on.
     
    Last edited: Mar 7, 2011
  3. John Smith

    John Smith In the garage

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    Mounting it in a Tuffy will only limit the speaker output, not transmission. The tuning of your antenna and the size of the ground plane are going to affect your receive and transmit more than anything.
     
    Last edited: Mar 7, 2011
  4. emorth

    emorth

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    Wow! This thread has exploded since I last checked in.

    John Smith is correct. The ideal CB antenna is a 108 inch whip (1/4 wavelength at 27 MHz). The ideal place to put an antenna (any mobile antenna) is the middle of the roof. Highest elevation and a good ground plane. Ground plane???? Mobile antennas are actually only half of the required (dipole) antenna. The other half is the "reflection" of the antenna in the ground plane. When the antenna "looks down" it sees its reflection in the ground plane and thinks it is the other half of the antenna. The ground plane essentially fakes out the antenna. Trust me on this one, its a physics thing. When the antenna is mounted in a location that does not have a ground plane, the antenna looks down and doesn't see its other half and gets upset. So what happens? The SWR or reflected power can go up and the way the antenna radiates gets distorted. Ideally the antenna should radiate equally in all directions. Imagine a donut shaped radiation pattern around your antenna. With less than an ideal ground plane the "donut" radiation pattern will be distorted. Now, back to the real world, a 108 whip in the middle of the roof is a little impractical. Do the best you can. The CB antennas on truckers mirrors don't have a good ground plane and they seem to do OK. Mount the antenna in a physically good location, as high as possible, with as much of a ground plane as possible. Maryland State Police cars have whip antennas mounted on the rear fender. Not the ideal location, but the best practical location.

    Devilman, YES!!! 40s have lots of radiated electrical noise. Ask me how I know. Mine is terrible. I have installed braided ground straps, filtering and other tricks and I still have noise. Tough problem to solve. A work in progress. Stay tuned for updates.

    Regarding switching antennas, take a look at my antenna mount. It is a spring loaded ball mount with a quick disconnect for the whip so I can take if off or replace it with another antenna quickly. Link to one source for the quick disconnect: Hustler QD2 Quick Disconnect Check around other places may be cheaper.

    I will have test equipment to tune antennas at IPOR on the 19th. We can have an informal CB tech day and talk about antennas, antenna mounting locations, coax cable and connectors, wiring, electrical noise, and other stuff if anyone is interested. Let me know what you want to do so I know what test equip to bring.

    Anyone besides Devilmans Hand and Von Hayek intereste in amateur "ham" radio?

    Ed
     
  5. hakalugi

    hakalugi

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    I wanted something small so i got a Cobra 75WXST

    [​IMG]

    the cool part is, it's all in the grip/hand unit. so nothing large to mount. if you have > 1 car, then you get extra of these, AC 701:

    [​IMG]

    so you wire in that smaller unit, so you can take the transeiver between cars.

    it lacks the external speaker, but for limited use, it's fine - since you mount it high, so the unit and speaker are closer to your ears, vs. a full single DIN unit which is usually lower under the dash or between the seat and the center console.

    I had a small magnet mounted antenna for the roof, wasn't great on the highway with truckers, but worked for caravan'ing. but the '80's arb bumper has an antenna mount location, so i got a 4' Firestick for it. no feedback yet on the Firestick.
     
  6. hakalugi

    hakalugi

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    yes. i took advantage over the winter holidays to begin reading on eham.net and arrl - the basics. haven't take a course or bought exam books, but i'm interested in learning more.
     
  7. Luthier

    Luthier

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    CB & HAM equipment

    I wrote up a CB selection page for CLCC.ORG a long time ago: the URL is CLCC: CB Equipment and Selection

    With CB you really do want an "RF Gain" control if you intend to use the radio for close-distance vehicle to vehicle communication; without the RF Gain control the receiver will be overwhelmed (hard to understand) if the transmitting antenna is less than 100 yards away.

    If you have a 40 series, the fiberglass roof is not a very robust surface to mount to nor does it offer a very good ground plane (which improves signal radiation). Additionally if you have a 40-Series you will want to use good quality coaxial (antenna) cable to maximize the shielding (this costs only a few dollars more) because 40's (all 8 of the 40-Series I have owned) generate a tremendous amount of electrical noise.

    I agree the center-roof mounting antenna creates a more even radiation patern (the pattern is less diectional anf more omni-directional). However there is a big problem with doing this. A roof mounted antenna is a clearance problem in parking garages; so you have to remove the antenna indoors. If it is centrally mounted on the roof it is harder to reach than if it is offset.

    Unless you are using the radio to communicate all the time I think that a magnetic mount antenna is a good way to go. They require no drilling to mount, they can be easily removed, and if a low branch smacks it the antenna will simply come loose but will not damage the vehicle much. Magnetic mounts in my experience stay put at highway speeds so you can use them on the interstate. If you have 40-Series a magnetic mount will not stick the roof so you will put it on the hood or a front fender.

    I got a HAM radio license and if anyone has interest in getting one I would be glad to discuss the process of getting a license. The morse code requirement has been eliminated so if you lack an aptitude for code that is no longer a barrier.

    If you are interested in getting a HAM license contact me via email (I only get on this Forum about 12 times per year). There is no cost for a HAM license by the way.

    A good basic 2 meter HAM transciever like the Icom IC-2200 is curently $160 brand new (Ham Radio Outlet | ICOM IC-2200H | 2M 65W (DSTAR option IC-UT118)) and that includes free shipping. This radios transmitter will go as low as 5 watts for line of sight communication and has 65 watts output for when you need more range.

    If you are interested in getting a HAM license contact me via email (I only get on this Forum about 12 times per year).

    Most mobile CB's use 1/4 wave antenna's, however a 5/8 wave antenna will give you more range. A good 5/8 wave mobile CB antennas is sold under the "Firestick" brand name among others. Not all Firesticks are 5/8 wave so you need to read the fine-print.

    Regards
    -- Eugene (@) FJ45.com
     
  8. Luthier

    Luthier

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    Magnetic mounts / Firestick 5/8 wave antennas


    The Firestick uses a standard 3/8" x 24 thread so if you want to use it with a magnetic mount you will need that type of magnetic mount.

    Additionally the Firestick 5/8 wave CB antenna is a coil around a fiberglass core so it has more wind resistance which means that you might be better off using a 5 inch diameter magnetic mount instead of the little 3 inch diameter mag-base. The MFJ-335BT(Ham Radio Outlet | MFJ MFJ-335BT | 5 INCH MAG MT WITH 3/8 X 24) is a fairly reputable 5 inch 3/8" x 24 magnetic base.

    -- Eugene
     
  9. Blue77FJ40

    Blue77FJ40 SILVER Star

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    Mine's about 8 yrs old, it's been a good radio. My Wilson antenna is mounted on the spare tire carrier, and required only a tiny bit of adjustment. Guess I'm lucky, as I've not experienced any difficulties with electrical noise. Bill of Bill's 2 Way picked out a nice coaxial, antenna, and stainless quick detach mount for me.
     
  10. Devilmans Hand

    Devilmans Hand TLCA #19517

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    i'm just about to purchase a Uniden Pro 520xl
    $47.24+amazon shipping
    Amazon.com: Uniden PRO520XL 40-Channel CB Radio: Electronics

    Compact Size
    Rugged Microphone
    Instant Ch. 9
    S/RF Meter
    TX LE;D
    Channel Display
    Mounting Bracket
    Channel Selector
    RF Gain
    Squelch Control
    Volume Control
    PA Switch
    ANL Switch






    Now to just decide how to hook everything up.
     
  11. 76FJ40

    76FJ40 Old Fart SILVER Star

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    The only point I can add is NOT to leave any excess coax in a coil - Ed can explain why this is bad.
     
  12. hakalugi

    hakalugi

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    about the 5/8 wave antenna's - all the firesticks shorter than 7' meet that spec: CATALOG Main Page (Frame Setup)

    Model: KW2-? 2 Ft (61cm) 5/8 wave Rated @ 100 watts $19.99 (MSRP*)
    Model: KW3-? 3 Ft (92cm) 5/8 wave Rated @ 300 watts $21.99 (MSRP*)
    Model: KW4-? 4 Ft (122cm) 5/8 wave Rated @ 400 watts $23.99 (MSRP*)
    Model: KW5-? 5 Ft (152cm) 5/8 wave Rated @ 500 watts $25.99 (MSRP*)
    Model: KW6-? 6 Ft (183cm) 5/8 wave Rated @ 600 watts $27.99 (MSRP*)
    Model: KW7-? 7 Ft (213cm) 3/4 wave Rated @ 700 watts $29.99 (MSRP*)

    As Eugene noted, they're rather thick, so at highway speeds, they would develop more push/tip than an equal length standard thickness antenna.
     
  13. hakalugi

    hakalugi

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    hmmm, the long coax from my bumper has about 5' extra length - the PO seemd to need the length to run to the back of the center console - i'm going dash mount. is there a method to coil that doesn't produce the interference you're alluding to?
     
  14. 76FJ40

    76FJ40 Old Fart SILVER Star

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    Just don't coil the coax - use a rat's nest or just run the extra around your cab.
     
  15. emorth

    emorth

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    Just keep it as far away as possible from the ignition coil, distributor, spark plug wires, alternator, voltage regulator, wiper motor, and heater blower motor. All of these things are sources of radio interference.

    If you want to be totally fanatical, and be dangerously close to becoming a technogeek, the coax should be a length that is an odd multiple of a 1/4 wavelength or 108 inches for the CB band. 1 x 108 = 108, 3 x 108 = 324, etc. If not, don't sweat it.

    Ed
     
  16. emorth

    emorth

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    700 Watts! The legal limit for transit power on the CB frequencies is 4 Watts.
     
  17. Von Hayek

    Von Hayek

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  18. Devilmans Hand

    Devilmans Hand TLCA #19517

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    Ill be buying mine today. Trying to figure out What antenna I want. A firestik 4' tunable I think. Wondering if I can install the antenna in the stock radio antenna spot on the 40 with good results. Dunno what coax and connections are best. Found a cool dial switch to change between antennas too.
     
  19. Von Hayek

    Von Hayek

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    That's the antenna I ordered too :)
     
  20. Devilmans Hand

    Devilmans Hand TLCA #19517

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    Picked up the groundless plane 4' firestik firefly kit for $36 and a spring.