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In-Line Amplifier alternatives (to RCA D903)

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  • In-Line Amplifier alternatives (to RCA D903)

    Hello,

    So, about to launch into my first antenna project to boost range on my reciever (USB DVB-T) and I think I got a decent handle on what I want to do. However; among other things one issue particularly sticks out for me - the in-line amplifier.


    Seeing that the RCA Inline Amplifier (D903) appear to be the most comonly used I wanted to get a few myself, I mean - why invent the wheel again or try outsmart smarter people on this forum?


    Here is the issue:
    The RCA D903 appear to be discontinued, I can find new and used ones on E-bay and Amazon - but none will ship to Europe (Sweden specifically). So, hoping for some assistance finding alternatives that will work.

    I've looked at some alternatives such as Eagle Aspen 500335 950-2150 Mhz In-Line Amp but feel like I need to consult the experts (you guys) first.

    Appreciate any assistance.

  • #2
    Are you sure you need an amplifier?
    What RF sources are around you? The USB DVB-T has got plenty of amplification, but no inbound filter.
    If you are in a RF-noisy environment, which is in cities frequently the case, a 1090MHz filter brings more than an amplifier.

    Comment


    • #3
      Originally posted by RIN67630 View Post
      Are you sure you need an amplifier?
      What RF sources are around you? The USB DVB-T has got plenty of amplification, but no inbound filter.
      If you are in a RF-noisy environment, which is in cities frequently the case, a 1090MHz filter brings more than an amplifier.
      Well, I'm located next to a military airfield as well as a commercial - not sure if that is a good enough answer relating to my RF-environment. Maybe I need to outline in more detail what I'm about to do.

      Current setup:
      Raspberry Pi 3 with USB DVB-T dongle and stock antenna in bedroom window - see images.
      IMG_0727.jpg
      ESCF1_DVB-T_Stock_Antenna_range_160404.png

      The range is not terrible given it's location - range rings are at 50kms.

      Intended setup
      My intent is to install an antenna on the roof of my house - reasons would be obvious (beyond the fact that wife comments on "that ugly box and wires" in the window).

      So whatever antenna I decide to make (Spider, CoCo etc etc) it will be mounted outside and DVB-T dongle will be pretty far away either on the Raspi or NAS server wich is inside = X meters away.
      My approach is not to get away as cheap/simple as possible (this is fun) so I don't mind tinkering with gadgets (needed or not).
      Attached Files

      Comment


      • #4
        With RF environment I meant TV senders, GSM towers, Police, Firestation, Taxis etc... all those who are emitting unwanted signals.

        Hmm... Your wife should not be ignored.
        She will probably hate EVERY box an EVERY cable running along in HER home. Think about that!
        How comfortable do you feel going onto your roof?

        How far is that roof from your router? Is it in a WiFi range?

        My approach was to put power supply, Raspi, and receiver in an IP67 box directly on the roof, close to the antenna.

        The box needs only a power plug and has no other cables in your home. Everything is forwarded wirelessly. Kiss your wife for me!

        The antenna is a simple Jpole like that one:
        DUMP1090-Antenna2.jpg
        Since by design it is strongly resonnant and has a short, it is pretty insensitive to parasitic lower frequencies. So i did not need a filter, nor an amplifier.
        It is slim enough to fit into a standard PVC tube, so it's easy to make an outdoor design with standard electrical installation means.

        The final result looks like that:
        Kombimesstelle.jpg

        (here I have also included a noise-meter to feed the noise pollution of my neat neighbor EDDL to EANS.net)

        The Pi is fully remote controlled from my notebook (sudo apt-get install xrdp on the Pi and remote desktop on the Windows notebook)

        Regards.
        Last edited by RIN67630; 2016-04-04, 09:17.

        Comment


        • #5
          The WAF is maybe priority #1 in most home brew DIY's .

          In terms of RF noise - we'll have to see, I would think there is some with 2 ATC control towers (ESSL + ESCF) and numerous GSM masts in the vicinity.

          My house and backyard is all covered by my own WiFi (TPLINK ARCHER-C7 v2)...I can happily sit in my garden with my iPhone browser pointing to port 8080 on my Rpi.

          My plan was to mount a pole (hollow 2-3" dia) on side of house that extends up over the roof top by a fot or so - primary goal is to give antenna "omnidirectional" conditions.
          Whatever antenna I make goes on mounts that attaches to pole - cable runs back outside or inside pole through house wall into attict then through attict ceiling into *drumroll* closet where I have WAF permission to keep a NAS. I estimate we are looking at +15m of coax here (hence the Amplifier need).

          I will be looking at a DC inserter as well - anything that enhances the performance from antenna to dongle will be looked at. Just to be safe and "because I can" :P

          Nice setup with the Raspi! Plug-n-Play for real!

          But - my first hurdle is obviously to find an alternative to the RCA D903 amplifier ^^

          Comment


          • #6
            it becomes pretty clear that I lack some coverage - I hanged my indoor antenna out the window and reset my maxrange stats. The feed will thrive on in a roof top mounted position.
            ESCF1_DVB-T_Stock_Antenna_outsidemount_range_160404.png

            EDIT:
            Adding some photos of house:
            IMG_0731.jpg
            Wall mounted pole/pipe where vents are that extends up above roof.


            Bonus below - yeah, static noise, 2 x Blackhawks disturbing my feed.
            IMG_0730.jpg
            Last edited by Laban; 2016-04-04, 10:03.

            Comment


            • #7
              @ Laban:

              Eagle Aspen 500335 950-2150 Mhz In-Line Amp seems OK.

              DC inserter:
              http://www.ebay.co.uk/itm/381461511533
              Last edited by abcd567; 2016-04-04, 12:10.

              Comment


              • #8
                Originally posted by abcd567 View Post
                @ Laban:

                Eagle Aspen 500335 950-2150 Mhz In-Line Amp seems OK.

                DC inserter: http://www.ebay.co.uk/itm/381461511533
                Hello abcd567, thanks - I'll give it a shot and report back when tested.

                On order:
                Eagle Aspen 500335 950-2150 Mhz In-Line Amp
                ARPI-2000 Power Inserter
                Last edited by Laban; 2016-04-04, 12:05.

                Comment


                • #9
                  DC Inserter + AC/DC Adapter:

                  http://www.ebay.co.uk/itm/251211006217 (12V only, may not be suitable on long run of coax)

                  http://www.ebay.co.uk/itm/231194818253 (12V only, may not be suitable on long run of coax)

                  Comment


                  • #10
                    Originally posted by abcd567 View Post
                    DC Inserter + AC/DC Adapter:

                    http://www.ebay.co.uk/itm/251211006217 (12V only, may not be suitable on long run of coax)

                    http://www.ebay.co.uk/itm/231194818253 (12V only, may not be suitable on long run of coax)
                    What's your definition of a "long run of coax"?

                    The ARPI-2000 with a remote feeding DC adapter seem to give me a wider range of voltage (not sure I need that though).
                    http://www.antronix.com/files//DS-1020-SS_ARPI-2000.pdf

                    Also, would I be paranoid if grounding the antenna cable?
                    http://www.antronix.com/antronix-Products-Grounding.php
                    Last edited by Laban; 2016-04-04, 12:53.

                    Comment


                    • #11
                      (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, 15:06.

                      Comment


                      • #12
                        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).

                        Comment


                        • #13
                          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.

                          Comment


                          • #14
                            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!

                            Comment


                            • #15
                              @ 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).

                              Comment

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