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  • AM/FM/CB antenna

    anyone use a multi-purpose cb antenna for their am/fm radio reception as well? does it work well? do you need a special splitter of can you use anything that splits the wire? any down sides like conflicting signals? right now my radio antenna sucks and im thinking this could be the solution to the crappy radio antenna and needing a cb antenna.

    anyone have any experience with the antennas made by International? i guess they're not tunable.
    Last edited by joshs1ofakindxj; 03-17-2007, 02:40 PM.

  • #2
    i bought a special splitter and use my CB antenna for the AM/FM and CB. ive read everywhere that you dont' want bleed over. i haven't hooked it all up yet so i can't tell you if it will work good or not.

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    • #3
      well hopefully next weekend ill find out. if its ****ty then ill just hook the old radio antenna back up to the radio.

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      • #4
        When my radio is on, I have turn to the squelch almost all the way up on my CB for me to recieve anything.
        But always attested that to the fact that I have a crappy CB, it is the $50 Radio Shack special. I keep meaning to get a real one as I figured that would cure my reception issues but I have never gotten around to it.

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        • #5
          Some one is going to correct me here, but I'm throwing this out anyway.

          The antenna receives all frequencies within the wavelengths it was built to receive. It doesn't fliter out anything out of the wavelengths it can pick up. That is what you radios do. So technically, you can run as many radios off one antenna you want. The only problem with more radios/cbs on the one antenna is the strength of the signal the antenna receives is now being split many ways and getting weaker for every shared device it supplies signal to. So to solve this, a signal booster can be installed to boost the overall signal before being split to all the devices being run. So for the same price, you can just install another antenna.

          So yes, you can listen to your favorite radio station, and your CB at the same time. The only interference I could see is when you are broadcasting on the CB, it may cause barrage interferance.

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          • #6
            the biggest problem is when you transmit on your CB i was afraid it would destroy the reciever on the AM/FM, so i got the splitter that doesn't let the signal bleed between devices. i bought it from the company that makes firestick antennas.

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            • #7
              Originally posted by FUBAR
              the biggest problem is when you transmit on your CB i was afraid it would destroy the reciever on the AM/FM, so i got the splitter that doesn't let the signal bleed between devices. i bought it from the company that makes firestick antennas.
              Good call, I guess I wouldn't bet my stereo on the probability that the antenna manufacturer shielded the xmit lead from the receive side.

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              • #8
                Should be fine w/a stock CB, if the wattage has been boosted, or you have a booster inline you will most likely get some bleed through. I've ran both set-ups, an antenae for each and the single w/split. I never hurt the stereo, but had to shut it off when transmitting. That was OK becuase w/my hearing I couldn't hear the stereo and CB at the same time anyway!

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                • #9
                  yea, im thinking the radio is for on the road and the cb is for on the trail. 1 or the other.

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                  • #10
                    This is a little lengthy, but I think it will make the whole deal clear.

                    Yes,one antenna can be used for AM/FM and CB? But, don't have great expectations as to how you want your CB to work.

                    Back in the late 70’s a couple of manufacturers decided that they would connect a little electronic device to their AM/FM antenna and sell it to people as a 3-way antenna. On the surface, that appeared to be a pretty good idea. You wouldn’t need another antenna and thieves wouldn’t be able to tell that you had a CB in your vehicle (CB’s were being ripped off at a horrific pace). Unfortunately, CB operation with the set up was a huge disappointment.

                    The design of a "receive only" AM/FM antenna doesn’t really contain that much design at all. The biggest hurdles are the way you want/need it to mount on the vehicle, how tall you want it to be, and what do you want it to look like. If you did a resonant frequency check, you might have a hard time trying to find one that fell into either the AM or FM bands.

                    Why? Because it just isn’t that important to "receive only" radios. As a matter of fact, if you broke the antenna off of your vehicle you would probably still receive the major stations in your area. Granted, it may not be as good as when you had the antenna but you could still use the radio. And, if you had a metal coat hanger you could twist up a workable antenna in a few minutes.

                    Transmitting antennas (such as CB) are required to be resonant (design frequency that matches the radios output frequency) in order to operate. If they miss the mark somewhat you probably wouldn’t recognize the difference while in the receive mode. However, CB’s are also transmitters. In order for the antenna to absorb the radio’s energy it must be, within a fairly small bandwidth, on frequency with the radio. Failure to meet the transmitters needs means poor performance at least and damaged equipment at worst. Accordingly, in the 3-way antenna business, all design functions must first take into consideration the needs of the transmitters. Unless of course you don’t care how well the CB performed.

                    When a CB antenna doesn’t resonate in the general frequency ranges of the transmitter (wave length), the energy that cannot be absorbed by the antenna is reflected back into the transmitter (standing wave). High reflection results in highly heated components that will eventually fail. So what did the designers do? In order to protect the radios from going up in smoke they added a circuit in the antenna lead that would bleed away huge amounts of the radios power. What would you think of a tire business that sold you tires that would explode over 40 mph so they removed half of your spark plugs to control your speed? In effect, that is what WAS being done to the antennas in those 3-way set-ups.

                    If you want a 3-way antenna, start with the CB antenna. Get a good one! Then pick-up a tunable 3-way splitter (like a Firestick AR-1A). First, tune the CB antenna without the splitter in line to establish a set of reference points. Next, put the splitter in-line (connected to the CB, the AM/FM radio and the antenna) and recheck the SWR. Make any fine adjustments for the CB antenna with the appropriate adjusting device on the splitter. And finally, tune in a local AM broadcast station in your area and tweak the AM adjustment on the splitter to get best reception.

                    Finding an AM/FM look-a-like 3-way antenna today is a difficult task because the marketplace sent them packing after discovering the poor performance they deliver. However, if you end up with a disguise CB antenna, just don’t expect it to work very well. With your expectations set low, you won’t be too disappointed.

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                    • #11
                      I had always wondered about this, so im glad to see the topic going.

                      Just one question: I have heard alot of old timers who used these types of setups back in the hay-day of CBs say that they got vastly improved AM/FM reception using their larger CB antenna.

                      Does using a splitter like the one rstarch described give you that much better reception, such as picking up radio stations from farther away??

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                      • #12
                        Originally posted by fromasterJ
                        I had always wondered about this, so im glad to see the topic going.

                        Just one question: I have heard alot of old timers who used these types of setups back in the hay-day of CBs say that they got vastly improved AM/FM reception using their larger CB antenna.

                        Does using a splitter like the one rstarch described give you that much better reception, such as picking up radio stations from farther away??

                        Usually they do because of position only. They were usually mounted higher.

                        I have seen combo antennas that are triple strand. The outer strand is the broadcast antenna, with an RF interupter shielding the receive antenna. The other strands are for the AM/FM and the CB receive. Really the only tuning that has to be done is for broadcast (although I have to admit after tuning the broadcast, I seemed to receive better). As I said before, the antenna just absorbs wavelengths that it was designed for, and the FM tunes all the other stuff out by the frequency of the wavelength, the AM tunes off the Amplitude of the wave, and the CB by the...uh it's been a while, but I'm pretty sure it's by frequency also. The CB just is in a different band from the FM radio.

                        So really it isn't one antenna, it is three antennas all packaged into one. I have a few of those on my aircraft.

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                        • #13
                          Back when the multi band antennas first came out (at that time I was big time into CB), several of us purchased the combo antennas. What we got was essentiall a standard AM/FM with a 1/16 wave CB, coil loaded antenna sitting on top. Then essentially there was a power/frequency absorption filter with one cable going to the radio and the other to the CB that mounted under the dash

                          There really wasn't much problems with the AM/FM except on broadcast. Your radio blanked out altogether. Radio worked at the same time of CB reception.

                          The biggest beef we had was broadcast distance, it was pretty pathetic. We were accustomed to 1/4 wave (some guys had 1/2 wave mobile antennas) which gave 2 - 3 miles distance. The combos pretty much gave line of sight to any base station or mobile station. It didn't take us long to get rid of them. As 47driver indicates, lots of changes in technology have come about where the combo antenna design has improved.

                          Personally, I still won't own one because they are still a compromise in performance. It's hard enough to get a good broadcast pattern on a vehicle without limiting it's performance through antenna design. On safety and military applications, it's probably the saneist method though.

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                          • #14
                            I agree with you rstarch. You don't really know what you are getting inside these nice packages. There really has to be some sort of trade off when combining all the different wavelengths your trying to receive, then pack in a transmitting antenna on top of it.

                            I like the idea of having a specially made antenna for the CB, and a separate antenna for the radio. I just like to play devils advocate a little. I would think that there has to be a combo out there that worked as well as two separate antennas, but I think the cost would be the same (if not more) as two separate antennas.

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                            • #15
                              On a side note. My first CB was a Regency model CB-27. Tunable receiver for the entire 11 meter band (then channels 1 - 11) and three sockets for transmit crystals. You purchased a crystal holder and crystals designed for the holder. You then sanded and trimmed the crystal until you obtained the transmit frequency desired and mounted it in the holder. A few years later, pre-tuned crystals became available through the Tandy Corporation (Radio Shack) for about $10 ea (1970s value).

                              http://www.cbgazette.com/regency_Cb27.jpg
                              Last edited by rstarch345; 03-18-2007, 02:20 PM.

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