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  • ... if its placed at the antenna, and not just amplifying the noise.

    Sent using Tapatalk from my ZX81

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    • Originally posted by Rooster View Post
      ... if its placed at the antenna, and not just amplifying the noise.

      Sent using Tapatalk from my ZX81
      True, I fully agree with you. Please see my post #500 dated 17 December (in reply to Mike), which I am quoting below:
      "Amplifier's location should not make any noticeable difference if your cable run is not long (only 30 feet). However as a general rule placing amplifier close to antenna is desireable, as this way noise picked up by the coaxial cable along it's length is not amplified by amplifier"

      Sent from my N762 using Tapatalk 2

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      • Originally posted by Rooster View Post
        ... if its placed at the antenna, and not just amplifying the noise.

        Sent using Tapatalk from my ZX81
        Please see the picture of my 1/2 wave dipole. The cable length between dipole and amplifier is Zero.
        uploadfromtaptalk1387503469586.jpg

        Sent from my N762 using Tapatalk 2

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        • to be penadtic, the connections are actually feeder... lol im off to bed, thanks for the banter.

          Sent using Tapatalk from my ZX81

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          • Originally posted by abcd567 View Post
            True, I fully agree with you. Please see my post #500 dated 17 December (in reply to Mike), which I am quoting below:
            "Amplifier's location should not make any noticeable difference if your cable run is not long (only 30 feet). However as a general rule placing amplifier close to antenna is desireable, as this way noise picked up by the coaxial cable along it's length is not amplified by amplifier"

            Sent from my N762 using Tapatalk 2
            I guess using double shielded cable (if you could) might help as well?

            Regards,
            Gregg
            YSSY2/T-YSSY4 [SBS-1 Basestation w/- SSE-1090 SJ Mk2 Antenna (Thanks Delcomp) ] [Uniden UBCD996T w/- 16 element Wideband Discone VHF/UHF Antenna, and tuned 108MHz-137MHz Airband Antenna] [Trialing a home-brew 1090MHz collinear antenna]

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            • Originally posted by fungus View Post
              I guess using double shielded cable (if you could) might help as well?

              Regards,
              Gregg
              The increased sheilding will sure reduce noise.
              Common use cables RG6/RG58/RG59 etc have one shield of foil, overlaid by a braid.
              The Quad-shield cable has foil-braid-foil-braid.

              In situations where cable run is very long, or the cable passes through areas which have strong Electro Magnetic interference, use of Quad-shield is beneficial.
              In conditions encountered in normal 2 or 3 story houses, use of quad-shield is an over-kill.
              Last edited by abcd567; 2013-12-20, 06:28.

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              • Originally posted by mickopla View Post
                Here is a pic of my current set up. I want to incorporate the fr24 antenna in some way keeping the existing antenna and anemometer.
                [ATTACH=CONFIG]3085[/ATTACH]
                Mike, how do you like the arrangement of 2 antennas shown in picture below?
                Other experienced forum members are invited to give comments on this proposal.
                Alternate arrangement proposals are invited.
                Mikes 2 Antenna Proposal.jpg

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                • I would do what abcd567 has suggested (might be a bit concerned about wind load), what is the angled wire from the bottom of the collinear (is it a stay or a signal cable)?

                  an alternative might be to use something like this ... http://www.amazon.co.uk/Way-Satellit...YAS7CYDYJ0APNV

                  would have to see what the effect would be on the signal though.
                  Last edited by peterhr; 2013-12-20, 08:00.

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                  • Originally posted by peterhr View Post
                    I would do what abcd567 has suggested (might be a bit concerned about wind load), what is the angled wire from the bottom of the collinear (is it a stay or a signal cable)?

                    an alternative might be to use something like this ... http://www.amazon.co.uk/Way-Satellit...YAS7CYDYJ0APNV

                    would have to see what the effect would be on the signal though.
                    Thats a good suggestion from abcd567 but wind load could be an issue. In saying that the current set up withstood 90km/h gusts a few days ago without any issues. would have to guy wire it some more i'm guessing.
                    The angled wire from the bottom of the collinear is the signal cable. I need to tidy that up a little

                    Mike

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                    • Originally posted by peterhr View Post
                      I would do what abcd567 has suggested (might be a bit concerned about wind load), what is the angled wire from the bottom of the collinear (is it a stay or a signal cable)?

                      an alternative might be to use something like this ... http://www.amazon.co.uk/Way-Satellit...YAS7CYDYJ0APNV

                      would have to see what the effect would be on the signal though.
                      Two-antenna system requires installing second antenna, running 2nd cable, and reinforcing mast with guy wires, and continue worrying about wind load during windy days.

                      It is very easy and attractive solution to use one antenna & one cable, with splitter installed near the two receivers.
                      However splitters have insertion loss in the order of 4 to 5 dB.
                      Please see test reults for a few: http://www.axino-tech.co.nz/document...s%20tests.html

                      Most manufacturers will not declare insertion loss on the label of their product, but some professional ones do, like the one shown in the picture below:
                      Splitter-Insertion-Loss.jpg


                      Splitter loss covered by adding an Amplifier may be a workable solution.
                      Last edited by abcd567; 2013-12-20, 17:42.

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                      • You can use 'Two Antennas'..and still only need 'One Feedline' to the Receiver..by using a 'Phasing Harness'. Note: a pair of 50 ohm impedance antennas will now change to 100 ohms. The way to correct this, is by adding 1/4 wave lengths of 75 ohm cable, and using a 'Tee Connector' between them..to run your 50 ohm feedline to the Rx. Also remember, if your antenna has 3db gain..adding a 2nd should improve it by 3db..but you would need to add 'Two More' to get an additional 3db gain ! Use this info;
                        The Phasing Harness

                        A phasing harness is basically (2) sections of 75-ohm cable cut to odd quarter wavelengths X velocity factor, transitioning to a 50-ohm cable, which is usually the transmission line.

                        The exact length of the cable is important as it's a matching Q section. To determine the length of the line, use this formula.



                        Length in feet is the U.S. 1 foot measurement, or 12 inches. VF is the Velocity Factor of the 75-ohm cable. (Do not mix this up with 50-ohm cable).

                        Multiply 246 times the VF. For example, lets say you use RG-213 with a velocity factor of 0.66 or 66%. Your answer would be 246 x .66 or 162.36.

                        Next, divide this by the frequency. If we are operating at 7.100 MHz or 7,100 KHz, then we would take 162.36 divided by 7.1 or 22.867. So both sections of your cable would be odd multiples of 22.867 feet depending on the spacing of the antennas.

                        Jerry
                        F-CYQL1
                        Last edited by VE6CPP; 2013-12-20, 17:16.

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                        • Originally posted by VE6CPP View Post
                          You can use 'Two Antennas'..and still only need 'One Feedline' to the Receiver..by using a 'Phasing Harness'. Note: a pair of 50 ohm impedance antennas will now change to 100 ohms. The way to correct this, is by adding 1/4 wave lengths of 75 ohm cable, and using a 'Tee Connector' between them..to run your 50 ohm feedline to the Rx. Also remember, if your antenna has 3db gain..adding a 2nd should improve it by 3db..but you would need to add 'Two More' to get an additional 3db gain !.....................................

                          Jerry
                          F-CYQL1
                          Thank you Jerry for very useful info about connecting 2 Antennas to 1 Receiver.

                          Here the situation is somewhat different.
                          Basically it is issue of running 2 independent Receivers.

                          We were discussing following two alternatives:
                          (1) Each Receiver has it's own Antenna, requiring 2 Antennas & 2 feeder cables.
                          (2) Same Antenna and feed cable shared by both receivers using a cable splitter near the two receivers at ground floor, similar to running 2 TV sets with one antenna & feeder cable.

                          From your nick name 'VE6CPP' it appears that you are also an Amateur Radio Operator with call sign VE6CPP.
                          The first part 'VE6' of your call sign also indicates that you are from Alberta, Canada.
                          Am I right?
                          - .... .- -. -.- / -.-- --- ..- / .--- . .-. .-. -.--

                          .

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                          • Originally posted by abcd567 View Post
                            Thank you Jerry for very useful info about connecting 2 Antennas to 1 Receiver.

                            Here the situation is somewhat different.
                            Basically it is issue of running 2 independent Receivers.

                            We were discussing following two alternatives:
                            (1) Each Receiver has it's own Antenna, requiring 2 Antennas & 2 feeder cables.
                            (2) Same Antenna and feed cable shared by both receivers using a cable splitter near the two receivers at ground floor, similar to running 2 TV sets with one antenna & feeder cable.

                            From your nick name 'VE6CPP' it appears that you are also an Amateur Radio Operator with call sign VE6CPP.
                            The first part 'VE6' of your call sign also indicates that you are from Alberta, Canada.
                            Am I right?
                            - .... .- -. -.- / -.-- --- ..- / .--- . .-. .-. -.--

                            .
                            Option number two would be the best for me as i would only need the FR24 antenna and use it to feed both their box and a dongle. As long as the signal would not be affected in any way it may be a runner. Most importantly i would not want to cause any issues with the quality of data i would be sending to FR24 as an F Host.

                            Mike

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                            • Originally posted by mickopla View Post
                              Option number two would be the best for me as i would only need the FR24 antenna and use it to feed both their box and a dongle. As long as the signal would not be affected in any way it may be a runner. Most importantly i would not want to cause any issues with the quality of data i would be sending to FR24 as an F Host.

                              Mike
                              Since even low loss splitters cause an insertion loss of 4 to 5 dB, use an amplifier to boost back the signal.

                              Added later:
                              On a second thought, it is better not to connect anything to FR24 system, and run you system independently, a difficult solution, but does no interference to FR24 system & mo chance for violation of their terms of service.

                              Sent from my N762 using Tapatalk 2
                              Last edited by abcd567; 2013-12-20, 20:42.

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                              • Originally posted by abcd567 View Post
                                Since even low loss splitters cause an inaertion loss of 4 to 5 dB, use an amplifier to boost back the signal.

                                Sent from my N762 using Tapatalk 2
                                So in theory by adding the amp the signal could be boosted even beyond the default gain of the FR24 antenna?

                                Mike

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