1. Roger Oveur

    Funny enough theirs actually quite a few COMMERCIAL sites that already do this. One of options when you subscribe to their service is for marketing/object oriented knowledge ie: if your small/mid size company or designated keyword is mentioned in a news broadcast or in a police or emergency services radio traffic or any “air-wave utilized” technology etc. Kind of like a www search engine…but for the airwaves.

  2. phil

    I thinks it’s a case of “you get what you pay for”.Specs for a tv amp are far from what we need for our SDR programs. Looking at the images on his site, ADS-B has improved but the images showing the actual waterfall show a significant increase in noise (the opposite of what an LNA does). Save your $ and invest on proper LNA.

        • zac

          Poor dynamic range of the RTL and overloading are causing the problem you mention and your suggestion to buy a professional LNA is just a waste of money that will not resolve this problem. You cannot put a Ferrari engine in a Camaro
          and make it run like a Ferrari.
          Your “tv amp” is something that exist only for consumers; engineers, the serious ones, only see a circuit, a transistor and a datasheet. If you are not in the condition to read a datasheet and talk us about the transistor and a circuit stop trolling with trite statements.
          Commonplaces are the paradise of the unskilled tech.

          • snn47

            Zan and Phil without knowing how bad the Extraneous Signal Environment (ESE) is you cannot draw any conclusions from the increase in noise and spikes from a screen shot, and bench meassurements are the only way to prove who is correct with his assumptions.

            If I place a 1/4 antenna outside our lab, our state of the art spectrum analyzer is overloaded by several cell phone base stations a few hundred meter away (average peak -27 dBm). Despite a high dynamic range I cannot use the internal LNA, and have to add 20 dB of internal attenuation to enable RFI free measurement with a FSW (R&S) at 1090 MHz. Without adding very good filter to minimize the impact of the base stations that leaves only ~40 dB of dynamic range.

    • Mike

      ADS-B has improved. Period. The device provides value for the (very little) money. The actual measured parameters are irrelevant after this goal has been achieved.

      • snn47

        Even with Radio Line Of Sight to ground transmitter changes in propagation can significantly in-/decrease signal strength within a few minutes time. Therefore basing improvements on changes in signal strength measured at different times is not conclusive.
        Aircraft in movement are even more difficult as source. Aircraft antenna pattern and gain variation have been measured by FAA before instruction of Mode S to vary by more than 40 dB between lobes and notches. The pattern varies even for the same aircraft type with antenna placement on the aircraft fuselage, protruding objects and moveable gear like aircraft like rudder, flaps and landing gear. Aircraft are not always in level flight, but change flight orientation (~±30°) and flight direction (between 0 to 360 °).
        Therefore it is difficult to conclude that the LNA improved reception, without measuring at the same time in parallel. It is the same like wanting to believing any esoteric antenna gain for a cobbled together wire antenna construction.
        HAM radio operator have proven in the last century that you do it yourself a lot for nearly no money at all, but you have to understand the basics of physical and abide by them.

  3. rlwsdr

    Nice demo! Had no idea SDR Console supported ADALM-Pluto transmissions. I sure hope some kind of spurious emission filtering was applied to the output of the ADALM-Pluto :).

    The SDR console spectrum window showed a ton of splatter coming from the Motorola XTS 5000 III at an RF power measurement of -20 dBm. I’m guessing the handheld was relatively close by and just overloaded the poor Pluto. That got me thinking …

    Assuming the RF power measurement of -20 dBm is accurate; the handheld was transmitting 1 watt of power (30 dBm – lowest setting); and no extra antenna gain from the Motorola or Pluto SDR, the free space path loss of 50 dBm @ 400 MHz corresponds to a distance between the transmitter and receiver of 80 feet or so.

    RF power loss is greater if the transmitter is outside and the receiver is inside of a house. In that case, depending on the building materials between the transmitter and the receiver (masonry block, plaster board, wood, etc) a building RF loss of 7 to 10 dB @ ~400 MHz is possible. So the separation distance between transmitter and receiver could have been between 25 – 30 ft. But that’s all guessing at this point.

    I suppose the handheld could have transmitted into a dummy load and there would have been enough RF leakage for the PlutoSDR to receive it.

  4. Dan

    Hi, I saw a recent post on your website with a photo and a circuit diagram showing a wire jumper from C3 to the 3.3v land in the expansion port area of a newly purchased V3 dongle. The poster was wondering why it was there. An RTL-SDR.COM rep said that this mod reduced the noise on the HF band and that subsequent V3 dongles had the jumper etched on the circuit board. I have a V3, batch 2 dongle and am wondering if my dongle has this mod. If not, would it make a significant improvement to the S/N ratio if I added it, and what would the increased S/N ratio be? Thanks in advance!

  5. Dan

    I saw a post that showed a photo and circuit diagram of a fairly recent V3 dongle with a jumper going from C3 to the 3.3v land in the expansion port area of the dongle. Someone from RTL-SDR.com said that it reduced noise on HF and that subsequent dongles had the jumper etched on the board. I have a V3 batch 2 dongle and am wondering if that jumper is included on my board (wire or trace), and if not, would it make a significant improvement if I added this mod??? What would the S/N ratio increase be? Thanks, in advance!

  6. Dana VE3DS

    To summarize!!
    This should filter the amateur bands in R2
    50 – 54 MHz
    144- 148 MHz
    222- 225 Mhz
    430 – 450 MHz (420 – 450 MHz)
    1240 – 1300 Mhz
    2304 – 2400 MHz
    3400 – 3500 MHz
    if at all possible.

    • Marty Wittrock


      Please post your comments on the myriadrf.org site at: discourse.myriadrf.org and look for the post on the LimeRFE from @andrewback. Andrew is collecting comments to take back to the design team. So please do make those changes known.

      73 de Marty, KN0CK