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Thread: In-Line Amplifier alternatives (to RCA D903)

  1. #11
    Captain abcd567's Avatar
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    (1) Long run of cable:
    The power inserter ARPI-2000 does not determine the DC voltage. It is the Eagle Aspen Amplifier which determines the required voltage, and you have to use a AC to DC Adaptor accordingly.

    The Eagle Aspen 500335 950-2150 Mhz In-Line Amp has a rated voltage of 15 Volts DC. It will work ok with voltages from 11 to 18 volts DC.

    When DC current flows through a cable, there is a voltage drop. So if the DC adapter voltage is 12 volts, then for a short run of cable the drop may be about 1 volts, and your amplifier will get 12-1=11 volts, which is ok. If your cable is long (say over 15 meters), the drop will be more, say 3 volts, which means your amplifier will get 12-3 = 9 volts, which is not ok and will result in reduced performance of your amplifier.

    In case of cables longer than 15 meters, it is better to use 15 volts DC power supply, like this ones.

    http://www.ebay.co.uk/itm/221389012860 (it has a built-in power inserter)

    NOTE above model is for North America and AC Voltage is 120V, and has AC pins of US standard

    Grounding of cable sheild
    If you like, you can ground the shield of coax, to reduce static. It is not vital, but better.
    Last edited by abcd567; 2016-04-04 at 15:06.

  2. #12
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    Thanks all for taking the time and responding - appreciate it very much.

    DC Inserter / long cable
    I was actually thinking of getting a DC adapter that has adjustable voltage, these set you back a bit more but I think the benefit would be worth it. Based on your response abcd567 it only makes my belief in that direction stronger as it gives me more freedom where to physically place the DC adapter on the line as well as "boosting" the voltage to ending up where I want it.

    It might sound like I know what I'm talking about but that is a hoax - I don't, and my next question will prove it.

    The ARPI-2000 has a 500mA maximum current handling, the DC adapter I'm looking at states to deliver up to 1.5A @ 9-15V, 1.2A @ 18-20V and 1A @ 24V. The questions I have are:

    1. Am I getting into trouble here risking to fry the ARPI-2000 with the above 'uncontrolled' Amp?
    2. Where do one ideally position the DC Insterter & DC adapter on the line? Close to Antenna or Reciever?


    Home brew DC Adapter
    Instead of soldering the wires directly onto the coax cable I had this idea of "boxing" it using a SO239 where I solder the wires onto the coax adapter itself.
    xx-97511__62394.1269638034.1280.1280.jpg
    I have a hunch that this kit may reside int he attict where humidity could become a factor - besides, it works better with my OCD

    My general approach
    I'm separating the whole "project" into three sections (yeah - it's overworked but it's an occupational damage):

    1. Reciever (the dongle etc)
    2. Signal carrier (the cable)
    3. Signal reciever (the antenna)


    So far I'm working on the carrier bit (2) - how to give the best performance in carrying the signal from the antenna (3) to the reciever (1).

  3. #13
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    Be aware of the fact that good old SO-239&PL-259 connectors got the name "UHF connector" around last world war time.
    At that time 30MHz was "UHF"!
    This connector is absolutely not suitable for GHz applications!

    You might use a single SO239 as a mechanical frame for a cantenna, but please avoid using them as a coax cable connector.

  4. #14
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    Quote Originally Posted by RIN67630 View Post
    Be aware of the fact that good old SO-239&PL-259 connectors got the name "UHF connector" around last world war time.
    At that time 30MHz was "UHF"!
    This connector is absolutely not suitable for GHz applications!

    You might use a single SO239 as a mechanical frame for a cantenna, but please avoid using them as a coax cable connector.
    Woahh - saved me from potential disaster there. Not that I was planning to use it for anything else than the DC adapter and/or a base for a spider/cantenna - but I certainly did not take any consideration relating to usage as a connector for the coax cable(s).

    I'll read up on connectors - thanks again!

  5. #15
    Captain abcd567's Avatar
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    @ Laban:

    (1) DC Current Requirements
    The voltage requirement of Satellite Amplifiers is 15v dc.
    The dc current requirement is less than 50 mA (mili-amperes).

    The capacity of 230v AC to 15v DC power adapters is generally in the range of 300 mA to 2000 mA (2 Amperes). This is big enough to feed the amplifier load of 50 mA.

    The DC Power Insertors are pass-through and are rated around 500mA, which is sufficient as current flowing to amplifier is only 50 mA.

    (2) Location of Amplifier, Power Inserter & AC/DC Adapter
    These can be located anywhere on the cable from Receiver (DVB-T) to Antenna.
    The ideal location of Amplifier is close to the antenna.
    The ideal location of DC Power inserter is near the receiver (DVB-T).
    The practical location of AC/DC 15v Adapter is near the DC Power Inserter (due to limited length of AC/DC Adaptor's DC lead length).

  6. #16
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    @ abcd567

    Thanks for the patience and detailed answers - think I have sufficient information now to give it a go.

    I'll show progress in a separate thread for the project which I will name abcdRIN
    Last edited by Laban; 2016-04-05 at 18:34.

  7. #17
    Captain abcd567's Avatar
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    AMPLIFIER CONNECTION ARRANGEMENT


  8. #18
    Flight attendant JohnnyBravo's Avatar
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    Hi,

    I was just wondering if you've been able to install the amplifier and what the results are.
    Also, I would think that a 1090Mhz filter should improve your result further since the amplifier has a wide band of 950-2150 Mhz.
    This means it will also amplify other signals that are in that frequency range (GSM, etc.) so a filter should clean it all up nicely.

    Interested to hear how you get on!

  9. #19
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    Hello,

    Status update - waiting for parts....

    @JohnnyBravo: Good point, makes sense cleaning up the signal stream from unwanted clutter. Even if it may not be needed I see no reason not having one.

  10. #20
    Flight attendant JohnnyBravo's Avatar
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    I have one of these on the way which has a narrow band of 1070 - 1110MHz
    http://shop.kuhne-electronic.de/kuhn...fier/?card=351

    With power inserter
    http://shop.kuhne-electronic.de/kuhn...+Tee/?card=346

    Since the DC power goes over the antenna cable, I'd imagine that the quality of the power supply could have an effect on overall performance.
    Especially cheap power supplies are notorious for being noisy, so I figured I'd build my own one.
    It'll be an 'old-school' style transformer with some chokes and capacitors and none of that SMPS stuff (no offense).
    Ran a simulation of it and should be dead quiet, now time to build it all.

    Currently also awaiting parts, but will share the results as soon as it's all up and running.

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