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Need Help Setting Up Radio

Discussion in 'CB and Export Equipment and Accessories' started by Neuro, Jun 2, 2009.

  1. Neuro

    Neuro Member

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    First off I am new here! Glad to meet you all!

    I am working very hard to get a radio installed into my vehicle and it's been a real nightmare. I want to get as much range and performance as possible using the equipment I currently have but no one ever seems to give me a strait answer on anything related to CB.

    I currently own the following gear:

    Radio:
    Cobra 29 LTD NW

    Linear:
    Texas Star DX 250HDV

    SWR Meter:
    Dosy TR-1000



    Antenna:
    Cobra HG-A2000

    Could someone please detail the process of getting the following hardware to play well together and generally perform the way I want it to? No one will help me install it or answer even a simple question like where do I play my SWR meter. Before or after the Linear? Also what do I do about the SWR Cal on my radio? Do they both need to be used? How do I avoid jacking my radio up while trying to figure this out?

    Any help would be much appreciated!

    -Neuro
    #1
  2. Robb

    Robb Yup

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    First of all, I would hook up the radio and the antenna alone - w/o the linear and the SWR meter. Get the location of the radio taken care and mounted. Then put the antenna on the vehicle. The SWR meter buit into your radio might not be as good as the dedicated SWR meter you have, but it will get it close enough to know that the antenna doesn't have any issues.

    Before I go any farther - do you know how to use the SWR meter that is built into the radio? If you do, you are almost done.

    Check the SWR with just the radio and the antenna with the doors and trunk closed - and far enough away from any buildings or other cars that might affect the reading. Adjust/check the antenna SWR on ch 1, 20, and 40. I would try to get the SWR as low as possible on ch 20 - that is a happy medium.

    If you have adjusted and rechecked the SWR on the antenna to a satisfactory 1.5 to 1 - or less - then it is time to put the linear in. A 250 watt linear is going to need some sturdy guage wire to supply the amperage in order to operate correctly. Run a 8 guage wire from the +/battery to the +/red wire on the linear. Run a -/ground 8 guage wire to the frame and from the frame to the -/black wire of the linear. Don't operate the linear unless everything has checked out OK and the engine is running. Running the linear with the engine off will drain you battery down before too long.

    Use a 3 ft or 6 ft coasx cable/jumper between the linear and the radio. Re-check the SWR from the radio SWR meter. If the SWR is 1.5 to 1 or less - you are ready to go.

    BTW- I am not responsible if you don't assmble and adjust everything correctly. I urge you to find some local radio operator that can make sure that the job is all done correctly. Once he has done the job right, you will have learned how it is done and what to do if something becomes a problem.
    #2
  3. Neuro

    Neuro Member

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    First off thank you for replying! So a stand alone SWR Meter serves no purpose? Also the local radio techs are really expensive and tend to not know what they are doing. I had one of them tell me to use an orange extension cord to wire my amp into my car....
    #3
  4. Robb

    Robb Yup

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    I don't know much about the Cobra antennas. I've never owned one or used one. I'm not sure it will be satisfactory for decent receive and transmit. It may/may not be the 'weak link' in your system. Maybe someone else can chime in here and say something either way.
    #4
  5. Moleculo

    Moleculo Administrator Staff Member

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    The stand alone SWR/power meter is a good idea for testing. The meter built into the radio is good to get you close, but they're not all that great. If you have a 3' coax jumper, you can put the external meter inline to help you adjust the antenna more precisely. This is really what you should do first, as Rob suggested. After you get the antenna adjusted the way you want, then you can take it out of line and put the amp in it's place. If you have an extra jumper, you can put the meter in after the amp to measure the output of the amp. Whether or not you leave the meter inline is a matter of space/convenience, etc. Personally, I always take it out after I have everything set up. Oh yeah make sure that Cobra antenna can handle the power output of the amp.

    So to repeat: start the install with radio mounted, antenna mounted, coax run between them. Put the meter inline to adjust the antenna until the SWR is low. Don't even think about installing the amp until the antenna is good. THEN put the amp inline. Don't use extension cord wire for the amp...use about 8ga or so.
    #5
  6. loosecannon

    loosecannon break on through

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    I i may repeat some things that Rob said, but this should walk you through it.

    a couple of things first:

    1. im assuming that your equipment all works properly.
    if you bought it used, there is a chance that it does not.

    2. your radio might have too high of a deadkey for your amp.
    (the deadkey is the amount of power ((watts)) that your 29LTD puts out when you key the microphone but do not speak into it. a "dead" key)

    if it does, then you will have to modify the radio to work with the amp.
    the mod needed is called a "swing mod" and is pretty easy to do.
    we will deal with how to do it in another thread.

    lets get started.

    mount the 29LTD where you want it, and run the positive power wire right to the positive terminal of the battery. (MAKE SURE to fuse the positive lead right at the battery to prevent fires)

    find the closest spot to where your radio is mounted that is part of the chassis of the vehicle. (make sure its not just a small metal panel somewhere but actually is attached to the body and frame of the vehicle. a good determiner is if you see other things grounded to that same metal.)
    attach the negative wire from the radio to this metal keeping the wire as short as possible. around a foot is great, try not to make it over 2 feet or so.

    now you want to mount your antenna.
    i dont know of that cobra antenna you have is a magnet mount or not, but if it is, just stick it in the center of the roof of the vehicle. if you stick it on the trunk or some other low spot, you will not get out as far and might have SWR problems.

    if its not a magnet mount antenna, then hard mount it, but you might want to start another thread with all the specifics of your particular installation and get some help mounting it properly.

    ok, now connect the coax from the antenna to your external SWR meter using the connector on the back that is labled ANT (ANTENNA).
    you need to have a couple of coax jumpers for your install.
    dont buy them at radio shack.
    buy a couple on ebay that are either 3 foot or 6 foot, whatever works for your install. they should be made of RG-8x (also called RG-8 mini) coaxial cable.
    make sure whoever you buy from actually solders the connectors on.

    using one of your jumpers, connect one end to the SWR meter using the connector on the back that is labeled RADIO, or, INPUT, or whatever.
    connect the other end of the jumper to the back of the radio.

    now, turn the radio on, and set it to channel 20. make sure the CB/PA switch is in the CB position.
    turn the DYNAMIKE (microphone gain) all the way down. (counterclockwise)

    SWR SETTING PROCEDURE:
    now set the knob on the TR-1000 meter to "SWR SET".
    look at the meter on the TR-1000. you will see three different scales of measurement. the one that goes from 0 to 1000 is for measuring wattage.
    the middle one is for measuring SWR (Standing Wave Ratio, which we are working with now), and the bottom one is for measuring modulation.

    key the microphone and using the knob on the TR-1000 labeled "SET ADJUST" turn the knob until the needle goes all the way over to the right and aligns with the mark on the middle scale labeled "SWR SET".
    unkey the mic and be sure not to bump the SET ADJUST knob during these next few steps.

    turn the switch on the TR-1000 to the "SWR" position, key the mic, and make a note of the reading on the meter. (write it down!!!)
    ideally, the meter would not move to the right at all, that would be a perfect 1 to 1 ratio. (almost unattainable in the real world.)
    anything over 2 means you might have an antenna problem, but we'll get there later.

    now, set the radio on channel 1, and go through this whole SWR SETTING procedure again.
    make a note of the reading.

    set the radio on channel 40 and go through the whole SWR SETTING procedure again.
    make a note of the reading.

    now, if your reading is higher on channel 1 then your antenna needs to be adjusted to be a bit longer.
    if its higher on channel 40, the antenna needs to be a bit shorter.

    adjust the antenna in 1/4" increments. you will have to re-calibrate the meter each time you make any change, whether it be changing the channel on the radio or adjusting the length of the antenna.

    try to get the SWR to be about the same on both channel 1 and 40 and it should be below 1.5.
    if you cant get it below this, then you either have a mounting issue or need a new antenna. ( i highly recommend the wilson 1000 or 5000)


    i have to go now, but will continue with this tomorrow evening.

    good luck and please post your results if you try this before i continue.


    later,
    LC
    #6
  7. Neuro

    Neuro Member

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    WOW, man yeah thanks, I am awaiting the next part of this. This is what I am looking for! Thank You

    Edit: What do I do about the SWR Knob on my radio when using an external meter?

    My Antenna Specs:

    Cobra HG A2000 High Gear CB Antenna
    Power Handling Capability: 6000 watt
    Construction: 24/8 PowerCoil with 24 carat gold-plated 8-gauge copper coil
    Frequency Range: 26-30 MHz
    Connector: SO-239
    Type: Matched braided coaxial cable
    Part Number: HG A2000

    [​IMG]
    [​IMG]
    Last edited: Jun 2, 2009
    #7
  8. loosecannon

    loosecannon break on through

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    the SWR CAL knob on your radio works exactly the same as the "SET ADJUST" knob on your TR-1000.
    its job is to calibrate the SWR meter so that the reading will be accurate.
    you ALWAYS re-calibrate an SWR meter any time you check your SWR.

    your 29LTD has a built in SWR meter, and yes, we could have done the whole antenna tuning thing by connecting the antenna directly to the radio and using its SWR meter.

    the reason an external meter is better is because they are more accurate, and much easier to notice small changes on.

    if you want to do a quick test of the radio's built in meter, to see if it matches what the external meter is telling you, just do an SWR reading on the external meter just like i showed you in the last post.

    now, without changing anything else, set the switch on the radio to CAL, key the mic, and adjust the SWR CAL knob on the radio so the needle aligns with the mark on the meter labeled CAL.

    unkey the mic, switch the switch on the radio to SWR, key the mic, and compare the readings on the radios meter to the reading on the external meter.

    the SWR CAL knob on the radio is only for the meter on the radio and will not do anything to the external meter.


    ok, before i continue; that antenna looks to be ok for what you want to do.

    ive never used one, and dont know how well they are built, but if it works the way its supposed to, it should be fine.

    dont forget to give the antenna the 90mph test!
    you have to find out if that magnet mount will stay on at high speeds.
    you dont want it falling off and hitting another car.

    also, the location you have chosen to mount your antenna will result in a radiation pattern that favors the front of the vehicle.
    what i mean by that, is that you will get out further in the direction your vehicle is facing, and wont get out as well towards the back of the vehicle.

    if you put the antenna in the center of the roof, you will get out well in both directions.

    now to pick up where we left off:

    you have just set the SWR of your antenna, and still have the meter hooked up in line between the radio and the antenna.

    turn the switch on the TR-1000 to the position marked "30".
    this is the 30 watt scale on the meter. if you look just under the numbers going from .3 to 1000, you will see another set of numbers going up to 30.
    use this scale when reading the output of just a radio, and use the position marked "1000" when reading the output of a linear amp.

    that makes sense doesnt it?

    now, key the microphone and note the wattage reading.
    most likely it will be somewhere around three to four watts.

    turn the DYNAMIKE (mic gain) all the way up. (BTW, unless your radio has been modified, you should always leave the DYNAMIKE all the way up. it doesnt really increase your talk power, it just decreases it if you need to for some reason, like checking your SWR)
    now key the mic, and, with your mouth about 1" away from the mic, say, "TEEEEEEESSSSSST" for long enough to get a reading on how far the needle on the TR-1000 swings to the right while you are speaking.
    (FYI, you should always talk with your mouth about an inch away from the mic for best audio)

    what you have just measured are your "deadkey" wattage, and the "swing" of the audio.
    write these numbers down and tell me what they are, phrasing it this way:
    "my deadkey was X watts, and the swing was XX watts."


    now for the amp hookup.

    there are way too many variables involved in setting up a linear amp in a car for me to go over in one thread. the amp may have a high SWR for some reason, it might mess with the vehicle's computer, etc...
    RF is a finicky beast to say the least.

    i will tell you how to hook it up, and if problems arise, you might have lots of reading and learning to do to get it to work right. ok?, ok.

    so, first pick where you want to mount the amp.
    my suggestion is to mount it within a few feet of the radio, in a place that will allow air to pass over the heatsink fins.

    run the positive wire from the amp directly to the positive terminal on the battery, and be sure to adequately fuse the wire right at the battery to prevent fires.

    if the wire length is 10 feet or less, you can use 8ga. wire.
    if the length gets over 12 feet or so, you should step up to 4ga. wire.
    car stereo places have the right stuff, and will also have the correct fuse holder.

    keep the ground wire on the amp close to a foot in length, and really try not to go much over that.

    you need to find a REALLY good ground to mount the ground wire to.

    sometimes a seat bolt will work, but many times these bolts have glue or adhesive on them, and dont make a very good connection with the chassis of the vehicle.
    you may have to drill a hole to get a good ground connection.
    just be careful not to drill into your gas tank, transmission, etc... LOL

    whatever location you choose, you will have to sand off some paint and make the connection all bright and shiny metal to metal.

    try to find some pics on the net of how others have done theirs.

    now to connect the amp inline with your radio and antenna.

    disconnect all cables from the radio and the meter and start from scratch.

    connect a coax jumper from the back of the radio to the connector on the TX250 linear amp that is labeled "IN" or "RADIO" or whatever.

    connect a coax jumper from the TX250 connector labeled "OUT" or "ANT" or whatever, and connect the other end of this coax to the TR-1000 meter where it is labeled "IN" or "RADIO" or whatever.

    now connect the coax from the antenna to the TR-1000 meter where it is labeled "OUT" or "ANT".

    now we are going to check the SWR going in to the amp, and the SWR coming out of the amp, so to speak.

    first, start with the radio on, and the amp OFF.
    set the radio to channel 20, and turn the DYNAMIKE all the way down.

    set the TR-1000 switch to "SWR SET", key the mic and calibrate the meter the same way we did before.
    now switch the TR-1000 to SWR and key the mic. note the SWR reading.
    it should not have changed much at all from when you checked it without the amp inline.

    if it did, you have an installation issue and need to go back and re-check all your steps.

    we are about to turn the amp on, but before we do, you need to understand that this amp has different power levels, and by pushing certain buttons, you will get different levels of power. find a manual online to learn about how to select the power level you want.

    right now we will leave it on HIGH, which is all buttons out except the red one, which is the power switch. the white button is a receiver pre-amp and will increase the receive gain of your radio. it will not affect the power output of the radio or the amp.
    i find that these pre-amps just increase the noise level and dont really use them.

    so, with the amp on, re-calibrate the TR-1000 and check the SWR.
    you will notice that when adjusting the needle during calibration that the needle is much more sensitive to knob movement. this happens when using more power.

    the SWR with the amp on should not be over 2.
    if it is, you have problems, and need to keep your mic key ups very short while trying to fix the problems.
    dont try to talk using the amp until you get the SWR down below 2.

    now we are going to check the SWR coming in to the amp.
    with the amp inline and on, calibrate the SWR meter in the radio, and check the SWR on the radio's meter just like we did before.

    this reading should also be below 2.

    if both readings are below 2 then you are ready to rock!

    now switch the TR-1000 to the 1000 position and check your deadkey and swing wattage with the amp on. (dont forget to turn the DYNAMIKE back up!)

    make a note of all these readings and post them as you go through this procedure.

    we will look at the numbers you are getting for both wattage out and SWR readings, and go from there.

    make sure to actually write down all these numbers, dont just try to remember them. LOL

    good luck,
    LC
    #8
  9. Robb

    Robb Yup

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    A couple of points.
    1) Mount the antenna in the center of the roof for better output/receive. I put my antenna there, and that is where it will work the best - as a rule.
    2) The SWR knob on your radio doesn't adjust the actual SWR; it only calibrates it to give you the proper reading. It does NOT match your antenna to the radio! The SWR knob does nothing at all when you are transmitting or receiving - it is merely an adjuster knob to CALBRATE the SWR. DO NOT make the mistake in believing that it is actually making up the difference/tune of the radio and antenna.

    IMPORTANT!
    If you DO NOT know how to do the SWR cailbation and adjustment, your best bet is to find a radio operator in your area that does and persuade them to help you.
    IF THE SWR ADJUSTMENTS AREN"T MADE CORRECTLY, YOU WILL DAMAGE THE RADIO AND THE LINEAR!!!
    #9
  10. kd-5-bgt

    kd-5-bgt W9WDX Amateur Radio Club Member

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    From what I have seen the above posts are pointing you in the right direction,just be sure to follow the steps as posted to the letter,as stated above if you do not have your swr as low as you can get it you will damage the radio and/or kicker.

    I took a close look at the antenna ,is that a magnet mount or a trunk mount? That could very well effect your tuning for low swr.....looks like a trunk mount from what I can tell

    High swr translates into heat buildup in the radio and/or kicker....heat is a bad thing as I am pretty sure you are aware of.

    The kicker will have heat buildup reguardless,a high swr will cause the heat to build faster than it normally would.

    So just take your time and be sure you have everything right.....and enjoy !! A few extra minutes is well worth taking when a high dollar radio or kicker is invloved
    #10
  11. Neuro

    Neuro Member

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    The antenna is a magnet mount and that is not my vehical above there. I just needed to show you guys what the antenna looks like so I found that. I have the antenna in the center of my roof as written above. Ill go ahead and collect the numbers for you and post them. Once again I appreciate your help. I really want to learn how to do it as opposed to having someone else do it. Thank you again.

    Edit: Quick question, does amp power stack? Some radios offer a belly pack, when using power gain from the radio through an amp does it stack?

    Edit: I had all my jumpers made today, two 3ft and one 12ft because I plan to run my amp inside the trunk. So I plan the following setup:

    RADIO > ( 12ft ) > AMP > ( 3ft ) > METER > ANTENNA
    Last edited: Jun 4, 2009
    #11
  12. loosecannon

    loosecannon break on through

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    im not sure what you mean by the first question, i think its your use of terminology that is throwing me off. i will read it again and post if i come up with something.

    as for the way you are going to set everything up, i cant tell you whether your chosen amp location will be a good thing or a bad thing.

    sometimes problems arise when power wires to amps get too long.
    sometimes problems arise when amps are mounted too close to engine computers.

    one thing i can tell you for sure, is to temporarily set this up before you run wires underneath carpet and coax through body panels.
    if you tear your car apart to get everything where you want it, and then it doesnt work right, you are going to be very dejected and probably pissed!

    mount the radio permanently first, set the SWR using the external meter like we discussed before, and get that far before you start the next phase.

    when you are ready to test run the amp install, run your positive wire from the battery, (fuse!), through the firewall, and just lay the wire in place all the way back to the trunk. do the same for the coax going from the radio to the amp.

    one rule of thumb for amp installs is that power wires and coaxial cable dont like to be next to eachother.
    best thing to do is run the coax down one side of the vehicle and the power wire down the other.

    keep the ground wire short and attach it to a bolt that goes right to the frame if possible. make sure to remove paint on the ground connection point.

    run the coax to the antenna roughly in the same path that it will take when you have installed everything permanently.

    it is very important to set this all up in the places they will be when its installed permanently because the placement of things in relation to the placement of other things can affect your outcome GREATLY!

    also! make sure you test the setup with the engine running to make sure you dont have any computer issues.

    and remember that this amp can draw upwards of 30 amps when you are talking, so check the rating of your alternator to make sure your headlights wont dim every time you key the mic and talk.
    too much draw on the alternator can also be bad for the vehicles computer.

    you are going to find it difficult to key your mic and look at your meter at the same time with the setup you have in mind.
    you might want to think about a longer jumper to use from the amp to the meter.
    unless you have a friend to help you which is highly recommended!

    good luck!
    LC
    #12
  13. Neuro

    Neuro Member

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    Alright guys I have it all installed. I haven't done my SWR checks yet nor have I used the amp etc. It's still waiting for the initial tests. However I had my radio modified at the local shop and had the deadkey brought down to 4 Watts. Now when it stops raining out Ill have someone key up while I read the meter and get the numbers for you guys. So far I've done everything I've been told. My radio however is installed using a 20 Watt Bandit filter via fuse tap under the dash where the radio is mounted.

    Now there was a man at the radio shop who has his AMP fuse tapped into the fuse box is this a good idea? It turns on when he starts his car, which I suppose what he intended when doing it.

    As to get back to my question that was worded incorrectly I asked the guys at the local radio shop this question:

    If they sell radios with built in amps which they call belly packs, what happens when using an amp? If you have an amplified radio output of so many watts 100~+ what the hell happens when it hits the amp "if you install one inline with the radio" does the output of the radio and amp power add up? They told me that it does add up. However after cross checking it with other people I was told it was not possible and that the radios need to be brought down to 4 watts to drive the amp. Is this true or false?
    #13
  14. Robb

    Robb Yup

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    I think I understand your question about 'stacking amps'. The answer is both yes and no. If you were to get a 1200 watt amp, then it would need a 'pre-amp' type of amp that puts out about 50-100 watts. In your case, the answer is no.

    The amp you have needs to have a certain amount of input watts to function without distortion or overload. Your radio is probably putting out 4 watts and swings upwards to about 10-12 watts. That would be adequate to drive the 200 watt amp you have. Should be fine.

    Since you are at a shop, I would ask them to check your SWR for you, since they set up your radio's tune. It wouldn't take long for them to set it up right. It would be the best way to do it - IMO. After the adjustments, then it would be all right to put the amp in with the jumper coax. Then, have them check the SWR again. If it checks out all right once again, then you are good to go...
    Last edited: Jun 4, 2009
    #14
  15. loosecannon

    loosecannon break on through

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    the Texas Star 250 likes a deadkey of about 2 to 2.5 watts.
    will it work with a 4 watt deadkey? probably, but your audio may not be as loud and the amp may heat up faster.

    im surprised the guys at the shop did not know this. it is pretty common CB knowledge.

    ask them how they turned the deadkey down in your 29LTD.
    there are right ways, and very wrong ways.

    as for wiring the radio to a fuse block. as long as the lights on the radio meter dont dim when you talk into the mic, and as long as you dont have any receiver noise, then you should be fine.

    the amp needs to go directly to the battery.
    there are no wires in your vehicle that are big enough to handle the draw of that amp safely.

    let us know how it goes.
    LC
    #15


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