Announcement

Collapse
No announcement yet.

best antenna

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Originally posted by YWYY View Post
    Herman, once the 2 parts of the driven element are poked through the holes and meet inside the pipe, I bent the ends at right angle with a pair of needle nose pliers, solder the coax directly to the bent ends, that way the coax will lie straight along the pvc pipe.......
    [ATTACH=CONFIG]5214[/ATTACH]
    Very neat and crafty (the feeder connection, as well as the antenna as a whole). Well done YWYY!

    Comment


    • Thanks for the information YWYY!
      I will try and copy your build sometime. The design you are using gives a wider angle of reception than the one I did a few weeks ago. What one can also do, on the inside where the 2 driven elements come close together: perhaps add a small piece of plastic or some non-conductive material, just to make sure they do never touch or short (due to water ingress)

      Comment


      • I have 2 satellite amplifiers. Will there be any benefit in adding the second one to the downlead so the 2 are in series?
        T-EGUB1

        Comment


        • Originally posted by trigger View Post
          I have 2 satellite amplifiers. Will there be any benefit in adding the second one to the downlead so the 2 are in series?
          I have initially used 2 amplifiers in series with my 50 ft RG6 cable between antenna & receiver, thinking that two amplifiers will be better than one. Later, when I removed 2nd amplifier to see the affect, I did not notice any reduction in range or number of planes. Since then I am using only one amplifier.

          For longer cable runs, or very lossy cable, two amplifiers are likely to be better than one.

          If you already have 2 amplifiers, add the 2nd one and see the effect.
          Last edited by abcd567; 2014-12-17, 18:00.

          Comment


          • Originally posted by abcd567 View Post
            If you already have 2 amplifiers, add the 2nd one and see the effect.
            OK I'll give it a try. Hopefully this won't happen burned1.jpg
            T-EGUB1

            Comment


            • Originally posted by trigger View Post
              OK I'll give it a try. Hopefully this won't happen [ATTACH=CONFIG]5215[/ATTACH]
              Ohhhhhh...
              It is the power supply which supplies the burning energy, not the amplifier.

              The current drawn by each amplifier is less than 50 milli Amperes, with 2 amplifiers it is less than 100 milli Amps, which is far too low to cause burning of coax or connectors. The current flow is several amperes if there is a short, high enough to burn.

              How this burn happen? Short between core & shield at some point? Are your power supply & power inserters ok?

              I have once fried my power inserter when I carelessly connected a shorted top coco without a dc blocker
              Last edited by abcd567; 2014-12-17, 20:45.

              Comment


              • First cantenna (no amplifier, no power injector, 15 ft RG6 COAX) has been operational for 18 hours now. The results over the mini-antenna the usb dongle came with have been amazing, I have increased my range in almost every direction by 100%. I found the best enclosure for it too. You know those Clorox disinfecting wipes that come in the cylinders that you pull out in sheets like a tissue box? It's absolutely perfect for the size of the cantenna. Just drill a hole in the lid and feed the coax in. The locking mechanism that usually is used to pull the sheets out locks the coax in place. Only some tape was needed to block it from going through the hole the other way.

                Cantenna v1.0 with COAX through the lid.
                IMG_20141217_244624_106.jpg

                Cantenna v1.0 with Clorox disinfecting wipes enclosure.
                IMG_20141217_244658_044_crop.jpg

                Default Antenna Range:
                StockAntenna.PNG

                Cantenna v1.0 Range:
                Cantenna20141217.PNG
                Last edited by wxmeddler; 2014-12-18, 07:55.
                T-KFAR3

                Comment


                • Originally posted by wxmeddler View Post
                  First cantenna (no amplifier, no power injector, 15 ft RG6 COAX) has been operational for 18 hours now. The results over the mini-antenna the usb dongle came with have been amazing, I have increased my range in almost every direction by 100%. I found the best enclosure for it too. You know those Clorox disinfecting wipes that come in the cylinders that you pull out in sheets like a tissue box? It's absolutely perfect for the size of the cantenna...........
                  CONGRATULATIONS!
                  I like your ingenuity in using Clorox disinfecting wipes cylinder as enclosure.
                  Your range will further increase when you add an amplifier. What is current location of antenna? up on the roof?
                  Last edited by abcd567; 2014-12-18, 23:00.

                  Comment


                  • I have a cantenna which I like to call "cantuna". The tuna can is 100 mm wide and exactly 69 mm tall so it needs no cutting - just a hole for the BNC connector I used.

                    I did some tests the other day, comparing the performance of the F-feed box (F-YSCN2) and the cantenna connected to a DVB-T dongle (T-YSCN8) on a raspberry pi.

                    Firstly I swapped the antennas. The resulting range was very similar (about 160 nm) although the FR24 box resolved about three or four times more messages.

                    I then fed the cantenna via an amplified splitter to both receivers. Again the results were pretty similar as far as range was concerned, with the FR24 box resolving a lot more messages but with very little extra range.

                    Next up, I split the FR24 antenna to the two boxes. The performance of the DVB-T dongle remained about the same but the range increased to over 300 nm on the FR24 box.

                    This led me to the conclusion that the cantenna is pretty closely matched to the performance potential of the Pi and that a higher gain antenna may not be justified. I did not fiddle with the gain settings on the DVB-T dongle, and I believe this could reduce the noise floor and enable more messages to be decoded. Another issue could be impedance mismatches between the antennas and the receivers, as well as the performance of the splitter amplifier, which is designed for TV signals.

                    In normal use, the FR24 bundle will track about 40% more aircraft than the Pi-cantenna bundle.

                    I only plotted data for about an hour on each test, I will repeat the tests but over a full day and see if I can get more accurate results.
                    Last edited by stanno; 2014-12-18, 07:53. Reason: Removed link

                    Comment


                    • Originally posted by abcd567 View Post
                      CONGRATULATIONS!
                      I like your ingenuity in using Clorox disinfecting wipes cylinder as enclosure.
                      Your range will further increase when you add an amplifier. What is current location of antenna? up on the roof?
                      I wish I had a roof. No, I live on the second of four floors of an apartment complex. It it currently zip tied to the banister of my balcony, hence the 180 look to the plot. I keep pestering my land lord to let me know if a similar sized apartment opens up on the 4th floor, I bet I could get 350-400km easy without a amplifier then.
                      T-KFAR3

                      Comment


                      • Have you guys not heard of Ghosting,..And Signal to noise...

                        Id would watch out,. When deploying an Amplifier,. That your not creating more noise than the signal.
                        (F-EDLE1)delcomp-DEL-David Tks(My friend Mike, all three of them)

                        URL: http://banner.flightdiary.net/EDLM
                        1090SJ(Ae) /(6m. Ecoflex10) / SBS 3 /-FR24 Box/ Power-line Connection (Ethernet)

                        Comment


                        • Originally posted by stanno View Post
                          I have a cantenna which I like to call "cantuna". The tuna can is 100 mm wide and exactly 69 mm tall so it needs no cutting - just a hole for the BNC connector I used.

                          I did some tests the other day, comparing the performance of the F-feed box (F-YSCN2) and the cantenna connected to a DVB-T dongle (T-YSCN8) on a raspberry pi.........
                          Thank you for experimenting & sharing your results/observations.
                          That is how we humans have reached today's level of intellectual, scientific & technical advancement.
                          Continue experimenting & sharing.
                          Last edited by abcd567; 2014-12-18, 21:00.

                          Comment


                          • Originally posted by wxmeddler View Post
                            I wish I had a roof. No, I live on the second of four floors of an apartment complex. It it currently zip tied to the banister of my balcony, hence the 180 look to the plot. I keep pestering my land lord to let me know if a similar sized apartment opens up on the 4th floor, I bet I could get 350-400km easy without a amplifier then.
                            Don't lose heart, you are not the only one facing this problem. I also live in an apartment, with no roof access, and my coverage is also only 180 degrees, and even in this semi circle, there are many sharp dips in range due to many tall buildings around.

                            Comment


                            • Originally posted by delcomp View Post
                              Have you guys not heard of Ghosting,..And Signal to noise...

                              Id would watch out,. When deploying an Amplifier,. That your not creating more noise than the signal.
                              Thanks for raising the caution. Most hobbyist don't know what is noise & what are it's implications, but a substantial number of hobbyists are aware of it.

                              The low-cost satellite in line amplifiers we use have Gain generally 12 dB to 20 dB. The noise figure lies in the range 3 dB to 7 dB, exact value depending on manufacturer & model.

                              Looking at above noise figures is a bit frightening, but our practical experience (with satellite/cable TV Dish & for last two years with DVB-T USB Dongle for ADS-B) show that this noise figure does not cause any noticeable problem. After all, some of these amplifiers are produced by reputable companies like RCA, Phillips, Channel Master etc. If these amplifier were creating so much noise as to affect performance, these reputable companies will not market it.

                              The in line amplifiers with noise figures below 1 dB (e.g. 0.3 dB & 0.5 dB) are also available, but the price tag is very high, which makes these unsuitable for hobby use.
                              Last edited by abcd567; 2014-12-18, 18:06.

                              Comment


                              • The trap that is so easy to fall into here is to add an amplifier INSTEAD of improving the antenna system !

                                The best thing to do is install a better antenna, then better feeder... or even remove the feeder (ive had success with a TV dongle at the base of the antenna, using CAT5 cable + USB extenders back to the shack)

                                But this is a double edged sword... the better the antenna system the more noise it 'could' gather...

                                Id advise ONLY using amps to overcome cable loss.

                                Comment

                                Working...
                                X