My home made RC Submarine

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  • RCSubGuy
    Welcome to my underwater realm!
    • Aug 2009
    • 1768

    #16
    No way to convert a GHz radio to mhz as far as I know, sorry...

    Comment

    • Bob Gato
      Captain
      • Feb 2019
      • 826

      #17
      Unless you are are better then average with electronics, I'd steer away from a used unit from Ebay-Bob's radio is one of the best deals for a 6 channel MHZ radio ($79!!) .
      Last edited by Bob Gato; 12-21-2019, 01:52 PM.

      Comment

      • MakeHobbyRC
        Lieutenant, Junior Grade
        • Dec 2019
        • 32

        #18
        Hi, and thanks for you suggestion. The transmitter is not expensive, but adding the receiver will make it a little expensive. Plus I had a, dare a say, brilliante idea, well more accurately, I found RC sub already using that principle, using a float connected to the sub via a wire, and the float will have the antenna on it, so no radio problems anymore. I need a piece of advice: If I want to extend the antenna by a wire, can I use any type of electric wire, or does an antenna requiert a specific type of wire (coaxial....). I am planning to solder a 2m50 long wire to the base of the antenna on the receiver (I am lucky because my rc receiver has 2 antennas, so if I fail this, their will be another antenna: redundancy..). Thank in advance for you help!

        Comment

        • RCSubGuy
          Welcome to my underwater realm!
          • Aug 2009
          • 1768

          #19
          You need to insulate any antenna extension by using coaxial cable. Standard cable will not work.

          Comment

          • MakeHobbyRC
            Lieutenant, Junior Grade
            • Dec 2019
            • 32

            #20
            ah thanks, this is precisely the point I was wondering about. What would you suggest I buy as coaxial antenna? Any diameter required ( for about 2 to 3 meters long antenna), any other technical specification I must be aware of before buying coaxial cable (type, diameter... ?), I know nothing about it. Thank in advance, very helpful information, Best

            Comment

            • He Who Shall Not Be Named
              Moderator
              • Aug 2008
              • 12253

              #21
              Originally posted by SubHuman
              You need to insulate any antenna extension by using coaxial cable. Standard cable will not work.
              Hey, Boss: I can't find it at the forum, maybe you can. Send this guy the link to my manual on how to shield the antenna wire between receiver and antenna proper. Some photos to wet this guys apatite.:





















              David
              Who is John Galt?

              Comment

              • He Who Shall Not Be Named
                Moderator
                • Aug 2008
                • 12253

                #22
                Originally posted by MakeHobbyRC
                ah thanks, this is precisely the point I was wondering about. What would you suggest I buy as coaxial antenna? Any diameter required ( for about 2 to 3 meters long antenna), any other technical specification I must be aware of before buying coaxial cable (type, diameter... ?), I know nothing about it. Thank in advance, very helpful information, Best


                David
                Who is John Galt?

                Comment

                • He Who Shall Not Be Named
                  Moderator
                  • Aug 2008
                  • 12253

                  #23
                  Originally posted by MakeHobbyRC
                  ah thanks, this is precisely the point I was wondering about. What would you suggest I buy as coaxial antenna? Any diameter required ( for about 2 to 3 meters long antenna), any other technical specification I must be aware of before buying coaxial cable (type, diameter... ?), I know nothing about it. Thank in advance, very helpful information, Best
                  Buy this: https://www.ebay.com/itm/RF-Coaxial-...0AAOSwcSxaUteJ
                  Who is John Galt?

                  Comment

                  • MakeHobbyRC
                    Lieutenant, Junior Grade
                    • Dec 2019
                    • 32

                    #24
                    Originally posted by SubHuman
                    You need to insulate any antenna extension by using coaxial cable. Standard cable will not work.
                    Can you tell me if " this https://www.aliexpress.com/item/3282...chweb201603_53 " coaxial would do the trick please? Need any-further information? Thanks a lot!
                    Attached Files

                    Comment

                    • cheapsub
                      Lieutenant Commander
                      • Dec 2019
                      • 187

                      #25
                      Sorry batter late then never.
                      all in Japanese but you get the idea.

                      I see you are using meter and a "," not '.' , so some where in Europe, switch to a used 40 MHz system, just to make things easier.


                       

                      Comment

                      • MakeHobbyRC
                        Lieutenant, Junior Grade
                        • Dec 2019
                        • 32

                        #26
                        Yes correct, France! Well spotted. And thank you, I am still waiting for the delivery of my coaxial cable, hope it will do the trick and be souple enough. We shall see...I will keep you posted ! Best,
                        William

                        Comment

                        • MakeHobbyRC
                          Lieutenant, Junior Grade
                          • Dec 2019
                          • 32

                          #27
                          Hi again! And just to update you and also to ask for advise maybe... I have been fitting the "antenna on a float". I have bought a coaxial cable, 5 meters long, and "connected" one end to the sub (via a 3 pin RC type plug, using the middle red cable for antenna cable, and the other two exterior cables for the "parasite coaxial cable". (hope the terms a understandable.)... And it ..... DOESN"T WORK!!! If we consider the soldering was done properly (very delicate) can it be the exterior antenna part, in the water bottle floating on the water that is not picking up the signal? Any need to solder the inner part of the coaxial cable (hence the antenna wire) to a straight stick of metal (To simulate an antenna)? Any suggestions.... ? Best to all and thanks in advance... advancing slowly but surely... ;)

                          Comment

                          • MakeHobbyRC
                            Lieutenant, Junior Grade
                            • Dec 2019
                            • 32

                            #28
                            Oh and what about a 35MHz radio control???? I have one... any chance under water? well you know what I mean I am not suggesting to use it underwater.. 35MHz would go through water?

                            Comment

                            • trout
                              Admiral
                              • Jul 2011
                              • 3545

                              #29
                              35MHz will travel through water and into your WTC.
                              If you can cut, drill, saw, hit things and swear a lot, you're well on the way to building a working model sub.

                              Comment

                              • Bob Gato
                                Captain
                                • Feb 2019
                                • 826

                                #30
                                Lets see if I have this right-you have a 5 meter coax cable soldered to your receiver where the old antenna was. Then it terminates in a floating water bottle. Then you asked about a straight stick of metal for an antenna. So you just have the coax with nothing on it? the shielding of the coax blocks all the signal and keeps it traveling to the end where there should be , yes, an antenna-EXACTLY the same size as the antenna that came off of the receiver.Also 5 meters might be too long to allow this to work. I also think the RCA plug will let water short out the signal from the center pin-IT MUST be watertight.There are more details that might cause failure but those are the big ones.

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