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  • It is important that the Whip's FINISHED length is 69mm from the rim of connector, as shown in the drawing below.

    If you have first cut the whip 69mm and then fixed it in position, it's FINISHED length will not be 69mm
    It will be be less than 69mm if left connector is used, and more than 69mm if right connector is used.

    Proper way is to first fix the whip in position, then measure and cut it to 69mm FINISHED length.

    Comment


    • Originally posted by trigger View Post
      I'm a few kilometers from RAF Benson and my Red Bull quarter wave antenna is seeing a lot more aircraft on the ground. They normally disappear at 200 - 300 feet. As far as long distance goes it is definitely down by about 50nm on my coiled Franklin.

      Is the reason that aluminium cans are recommended to avoid long term problems with rust? I have a Baked Bean can that I'll mangle this afternoon.
      (1) Red Bull quarter wave antenna is seeing a lot more aircraft on the ground:
      It is due to radiation pattern of the antennas. The 1/2 wave dipole has a higher gain than Franklin for nearby planes.
      Please see the drawing below.




      (2) As far as long distance goes it is definitely down by about 50nm on my coiled Franklin.:
      (a) Try larger diameter can (330mL Beer/Pepsi can dia 2-5/8 inch = 66mm).
      (b) Is your whip's FINISHED length 69mm? (see my post #1455 above)
      (c) Are you comparing the two antennas With or Without Amplifier?

      (3) Is the reason that aluminum cans are recommended to avoid long term problems with rust? I have a Baked Bean can that I'll mangle this afternoon.
      The reasons I used Aluminum can are:
      (a) Aluminum is non-magnetic.
      (b) Aluminum is easy to cut & drill hole.

      I wanted to try a can larger than standard drink cans. I could not find any made of aluminum. All larger cans were made of iron sheet. I then emptied a baked beans can (ate the beans for lunch) and tried to cut the can, but was unable to cut it, as the can was made of iron sheet and was harder than what my hand hacksaw could cut (I don't have a power hacksaw). I then gave up. The beans can had the advantage of larger dia & a flat bottom. I still want to give a try to such a can.

      Comment


      • Finished length is 69mm. I checked with calipers. calipers.jpg Both antennas are with an amplifier.

        I do have a pair of tin snips in the garage so I'll give the bean can a try later.
        T-EGUB1

        Comment


        • Originally posted by abcd567 View Post
          It is important that the Whip's FINISHED length is 69mm from the rim of connector, as shown in the drawing below.

          If you have first cut the whip 69mm and then fixed it in position, it's FINISHED length will not be 69mm
          It will be be less than 69mm if left connector is used, and more than 69mm if right connector is used.

          Proper way is to first fix the whip in position, then measure and cut it to 69mm FINISHED length.


          Of course, if you're using an amplifier - you just stuff the end of the amplifier through the hole in the can and screw it into position with a 3/8-32 UNEF nut (which you'd probably end up having to get from a female - female connector), then just poke the copper wire down the hole.

          ... still would need a radome to keep the rain water off the bits.

          Comment


          • Originally posted by trigger View Post
            Finished length is 69mm. I checked with calipers. [ATTACH=CONFIG]4600[/ATTACH] Both antennas are with an amplifier.

            I do have a pair of tin snips in the garage so I'll give the bean can a try later.
            1) Good that whip is of correct length. Good that you have vernier caliper to make accurate measurements.
            2) As I have mentioned in my earlier post, amplifier compensates for impedance mismatch of Franklin, and then Franklin gives a somewhat better range due to it's radiation pattern/higher gain towards horizon.
            3) I am tempted to purchase snips. I searched online & found a set of 3 aviation snips for $ 9.99 + Tax 13%, from Home Depot in my neighborhood. I will visit the store when I find time. http://www.homedepot.ca/product/3-pi...nip-set/974660

            Comment


            • Originally posted by peterhr View Post
              Of course, if you're using an amplifier - you just stuff the end of the amplifier through the hole in the can and screw it into position with a 3/8-32 UNEF nut (which you'd probably end up having to get from a female - female connector), then just poke the copper wire down the hole.

              ... still would need a radome to keep the rain water off the bits.
              Here is the concept put into practice...... Add an enclosure as described earlier












              .
              Last edited by abcd567; 2014-08-12, 18:06.

              Comment


              • I really like this, for the simplicity

                I need to get another voltage injector.

                How about poking half a franklin down the hole - what does that to to gain ... does it get us to the magic 400 - 450 km?

                Comment


                • Baked bean quarter wave. baked beans.jpg similar range to the Red Bull one. I'll try a Sweetcorn tin next as they are greater diameter than the baked bean tin.

                  Rainbow rainbow.jpg

                  The Silver Birch to the NNE causing a big dip in my range. Silver Birch.jpg
                  T-EGUB1

                  Comment


                  • Originally posted by peterhr View Post
                    .........How about poking half a franklin down the hole - what does that to to gain ... does it get us to the magic 400 - 450 km?
                    Replacing whip of dipole by upper half of franklin is a good idea. Don't really know how good it will perform, but it is worth trying.

                    Comment


                    • Originally posted by trigger View Post
                      Baked bean quarter wave. [ATTACH=CONFIG]4601[/ATTACH] similar range to the Red Bull one. I'll try a Sweetcorn tin next as they are greater diameter than the baked bean tin.

                      Rainbow [ATTACH=CONFIG]4602[/ATTACH]

                      The Silver Birch to the NNE causing a big dip in my range. [ATTACH=CONFIG]4603[/ATTACH]
                      Thanks for experimenting & sharing your results. What is the diameter of beans can?

                      Nice photos of your cantenna (can antenna), rainbow, & nice silver birch, though not so nice for your range.

                      Comment


                      • Originally posted by peterhr View Post
                        ..........How about poking half a franklin down the hole - what does that to to gain ... does it get us to the magic 400 - 450 km?
                        Well, on a second thought, if an amplifier is used, which will cover for high impedance/swr, why not also to try two simpler high impedance, high gain straight whips: the 1/2 λ (138mm) and 5/8 λ (170mm)?

                        Comment


                        • Works great I am happy with it, thanks abcd567


                          Originally posted by abcd567 View Post
                          .
                          If you have a long run of Coax, and want to add an amplifier to the Pepsi-can Sleeved Dipole, install it inside the enclosure beneath the Pepsi-can, like shown in sketch below (drawing is not to scale - lower part of amplifier may protrude outside the can, depending on make/model):

                          With Amplifier, so how about down in the bottom of the Coax just connect it to the receiver?

                          Comment


                          • Originally posted by 747-8F View Post
                            Works great I am happy with it, thanks abcd567




                            With Amplifier, so how about down in the bottom of the Coax just connect it to the receiver?
                            no, it needs a dc power inserter and a DC power source (12 - 18v) between the receiver and the cable to the antenna

                            see ebay item 161044085914

                            What this does is adds a DC voltage to the core of the coaxial cable to power the amplifier and also has capacitors to pass the signal but not the extra voltage down to the receiver

                            Comment


                            • Originally posted by 747-8F View Post
                              Works great I am happy with it, thanks abcd567

                              With Amplifier, so how about down in the bottom of the Coax just connect it to the receiver?
                              Originally posted by peterhr View Post
                              no, it needs a dc power inserter and a DC power source (12 - 18v) between the receiver and the cable to the antenna

                              see ebay item 161044085914

                              What this does is adds a DC voltage to the core of the coaxial cable to power the amplifier and also has capacitors to pass the signal but not the extra voltage down to the receiver
                              NOTE: Although I have built the CoCa Cola Can with amplifier, I have not put it to actual trial run. Logically it should work ok, but to be sure, I need to test it by trial run.

                              In the unlikely event that the "Antenna with Amplifier inside it" does not work properly, use the stand-alone antenna, cut the coax at a convinient location along its length (preferably close to antenna), and insert amplifier there.


                              DC Power Inserter:
                              Top (HF+DC) goes to amplifier/antenna
                              Bottom (HF) goes to receiver
                              Right (IN) goes to DC Power supply (12V to 18V DC depending on amplifier)

                              Last edited by abcd567; 2014-08-14, 21:52.

                              Comment


                              • I want to put it on top of the roof. I got an Amplifier, DC 15v and I made a DC power inserter same like the one you abcd567 made and you use it, but I am confused I don't know what to do what works or what's the best to use Amplifier.
                                Here take and look at the picture see what I got and what I know so far, but I can't do anything I want to be sure.
                                PepsiCan_Amplifier.png

                                What do you guys think? Any idea ?

                                Thanks

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