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Thread: Active diapason PCB antenna vice Coax Colinear 8 elements antenna

  1. #1
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    Active diapason PCB antenna vice Coax Colinear 8 elements antenna

    Hi All,

    I install an Active PCB diapason on my radio tower -12 meters above ground-
    There is a 50m long coax cable to the radarcape receiver, with 13 dB losses.

    I plot during 48 hours with SBS plotter the receive pattern and compare it with a previous pattern using the Coax Colinear 8 elements antenna with 10m Satellite TV coax cable 2dB losses

    Both curve are almost identical. The blue curve is for the Active diapason, and the yellow one for the CoCo.
    The Active diapason LNA compensate very well the 11 additional losses of the extra 40m coax cable.

    Maximum achieve distance is 245 nm

    Regards
    Francois /F5ANN
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  2. #2
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    Hi F5ANN,

    Interesting comparison, 50m coax is long! What cable was that?

    I suppose the use of 75 ohm cable for ads-b shouldn't be a concern now from your findings...

  3. #3
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    Hi,

    There are two coax cable. One 25M RG-213 which was already available in the tower, extended by 25 meters of satellite TV cable (20 dB/ 100 m losses at 1GHz) like RG-6.

    The mismatch due to 75 ohms and 50 ohms cable use does not contribute for more than 0.2 dB additional loss.

    This active antenna can support 75m of satellite TV cable, without loss of performances.

    Cheers
    Francois /F5ANN

    Quote Originally Posted by North Borneo Radar View Post
    Hi F5ANN,

    Interesting comparison, 50m coax is long! What cable was that?

    I suppose the use of 75 ohm cable for ads-b shouldn't be a concern now from your findings...

  4. #4
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    How you plot that coverage map ? (software) under Linux(ubuntu) .
    It is possible to plot without stop feed data to fr24servers?

  5. #5
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    Quote Originally Posted by mandrk View Post
    How you plot that coverage map ? (software) under Linux(ubuntu) .
    It is possible to plot without stop feed data to fr24servers?
    The original poster has unfortunately passed away so won't be answering you.

    However if you installed Dump1090-mutability as the decoding software you can do so from step 8
    https://forum.flightradar24.com/thre...-15-dev-on-RPi
    Posts not to be taken as official support representation - Just a helpful uploader who tinkers

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