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Thread: best antenna

  1. #11
    Team FR24 Mike's Avatar
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    I guess it's the same antenna, as I know that the one I recommend is produced in Russia.

  2. #12
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    Thanks, Mike!

  3. #13
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    Shame our currency is so bad here and we're so far away from anywhere.

    169.00 EUR = 257.104 NZD

    Ouch! DPD is more now too due shipping, works out about 215NZD

  4. #14
    Captain Birdie's Avatar
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    Quote Originally Posted by Mike View Post
    I have tried the DPD antenna and although it's quite tall, the results are not so good as you may expect. I would recommend this antenna instead http://web1745.kostenlos-onlineshop....action=details
    They look almost the same, but the difference in coverage is just amazing.
    The Antenna has a Gain of 10 dBi + Mast head Amplifier Gain of 12 dB ( i or D ?) = fantastic Gain = you might get signal beyond the curvature of the earth.

  5. #15
    Passenger mon's Avatar
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    Quote Originally Posted by Birdie View Post
    The Antenna has a Gain of 10 dBi + Mast head Amplifier Gain of 12 dB ( i or D ?) = fantastic Gain = you might get signal beyond the curvature of the earth.
    What data is this assumption based on?

  6. #16
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    Quote Originally Posted by mon View Post
    What data is this assumption based on?
    Based on this German Antenna:

    http://web1745.kostenlos-onlineshop....action=details

    AS-1090 Pre-Amplifier for 1090MHz
    Bild Vorverstärker AS-1090 AS-1090

    The AS-1090 is a pre amplifier designed specially for the Virtual Radar receivers SBS-3 and Radarbox. With such an amplifier the reception range of the SBS-3 is considerably extended. The AS-1090 can be used with any passive antenna like the GP-1090 or a discone antenna.

    An antenna pre-amp should always be mounted as close to the antenna as possible, not at the end of the (long) cable. If the pre-amp is used at the end of the cable (downstairs) it will still amplify the signal, but also the noise added by the cable. This results in a worse signal to noise ratio (SNR) and thereby in less effective decoding of signals. Another advantage of using the pre-amp right at the antenna is that you can use cheaper cable with higher attenuation for the long downlead to your shack.

    Technical Data:

    Frequencyrange 1030 - 1090MHz
    Gain 12dB
    Noise figure 0.9dB
    Supply voltage 12VDC over coax (remote)
    Power consumption 100mA
    Max. Input level +2dBm
    Connectors 2x N female
    Size 74 x 93 45 mm
    Weatherproof case for mast mount

    The AS-1090 includes all mounting hardware for mast mount. A Bias-T (DC injector) is not included.
    Order No.
    AS-1090 Pre amplifier 1090MHz 139.00 € Buy now
    Datasheet for pre amplifier AS-1090 (german, 320KB, PDF)

  7. #17
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    I think he means, how did you come to the conclusion you will see microwave band from around the curves in the earth.

  8. #18
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    Radio signal sometime behaves in strange manners. Possibly thru some reflections from the ionosphere.

  9. #19
    Passenger mon's Avatar
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    Quote Originally Posted by Birdie View Post
    Radio signal sometime behaves in strange manners. Possibly thru some reflections from the ionosphere.
    Then how does satellite communication work?

    Reflection on the ionosphere only occurs with much longer wavelengths and for troposcatter propagation the transmitter power of ADS-B stations is far too low. I guess the only reason for "strange" (i.e. unexpected) behavior in this case is the transmitter's altitude above ground level.

  10. #20
    First officer nzradar's Avatar
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    Quote Originally Posted by mon View Post
    I guess the only reason for "strange" (i.e. unexpected) behavior in this case is the transmitter's altitude above ground level.
    Not necessarily, atmospheric ducting as described here (http://en.wikipedia.org/wiki/Radar_horizon) also affects the detection range otherwise my range for all aircraft at FL370 would be exactly the same which in practice is never the case, some days its 180nm, others it's 250nm.
    Michael
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    New Zealand
    ex-FR24 Feeder

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