Recent content by Janos Konya

  1. J

    Wilkinson Splitter / Combiner

    Added to abcd's great description - to the size section: Manufacturers and designers have found a way to avoid having to use an overly large divider because of the lower frequencies. The possibility arises from the fact that the line can be described by electrical properties: the inductance of...
  2. J

    Wilkinson Splitter / Combiner

    It’s a good summary, but of course this scope doesn’t allow us to look at this useful stuff in a really detailed (analytical) way. "...and half is dissipated in the resistor" Well, it is true if signal entering in port 2 is out of phase compared to the quarter wave lines. - If input frequency...
  3. J

    Two instances of pfclient on same computer

    Hi @freddoair , If you want to eliminate a minor problem with the radiation pattern, doubling both the hardware and the software is not the way of "solution". Why don't you simply modify things only at the source of your problem? - Antennas, mainly colinear ones are sensitive to their height...
  4. J

    "GS code text file" is wanted for making dumpVDL2 output more readable

    Hello guys, Have you got a pre-filled text file for transforming the decoded hex code of the ground stations to ICAO, IATA, or friendly name with country code? dumpVDL2 already translates AC code from a basestation database - as you can see in "ac info" line. I need a solution for ground...
  5. J

    Logs

    Hello, From the latest (5.0.161) client update, log does not contain detailed info about number of planes or amount of sent data anymore. It is mainly for detecting if there is a problem with the connection. You can find stats for your station here, http://IP_of_your_station:30053/stats.html...
  6. J

    One antenna for two devices.

    Hi, It is possible but you need one really low noise and high gain (26-30dB) amplifier, and a low loss 2-way splitter-combiner. This latest is probably a 2-way Wilkinson combiner. Precisely splits the signal and you will have almost only the "natural" losses, originated from the splitting...
  7. J

    New - Predicted Range Tool

    Hi, I have already noticed the improved interface, thank you for your work. So far I have only felt in which directions the reception conditions have shortcomings, now I can easily compare it to the theoretical boundaries ... Best regards, Janos
  8. J

    Most common mistakes in construction of diy ADS-B antennas

    Practically, you can use this simplified format: 300 / 1090 /2 = half-wave = 137.6 mm then - lenght per dia ratio = 137.6 mm lenght / 1.5 mm dia = 91 (92 if you want) - Check second graph at the target (zero) reactance and find the common point of zero line and the 91 rate value. It is about...
  9. J

    Most common mistakes in construction of diy ADS-B antennas

    Sticking with 1.5mm wire:/ - When you get rid of unwanted reactance by shortening the antenna, the desired frequency will sneak out of the given bandwidth. This is why you have to use a bit "heavier" wire. Better bandwith will keep your antenna within the usable range. This extra shortening...
  10. J

    Most common mistakes in construction of diy ADS-B antennas

    If you want to create a dipole, you shall use the second graph first. - Read the lenght per dia rate at resonance and 0 ohm reactance first. (about 50, this gives you a wider bandwidth and the possibility to shorten the antenna so that the unwanted reactance can be cancelled. Detuning percent 7%...
  11. J

    Most common mistakes in construction of diy ADS-B antennas

    While using the diagram, you do NOT have to use also VF !! Use the original half vawelenght instead. 137.6 mm --> 130.6 by the original VF --> 130.0 to achieve the zero reactance With 2.6 mm dia wire, the ratio is about 53, then the resistance at resonance is about 57 ohm. Cutting a bit more...
  12. J

    Most common mistakes in construction of diy ADS-B antennas

    Hi, You can see the measurement result of one of my antennas above your post. ;) Of course, not all of them are "perfect". Accepting compromises possibly means the more likely healthy nerves for the rest of your lifetime. :) Some answers: 1) and 2) leg distance is about 6 mm between closest...
  13. J

    Is it possible to add a GPS receiver to the system?

    To finish my line of thoughts: - Syncing to stratum 2 and 3 servers over Internet is surely not the solution. Even wired network to stratum 2 or 3 can have 1 microsec sync error, depending on the protocol and the load. High and/or variable jitter value is not not ideal. There are timestamps, ok...
  14. J

    Is it possible to add a GPS receiver to the system?

    Now, I have a 0.1 microsec sync error... Maybe, we do not have to use laboratory class devices but it is enough to know the sync errors for all the cooperating stations to calculate the real position. Like in "exchange" This is a compromise, not perfect but (I think) a clever solution for...
  15. J

    Is it possible to add a GPS receiver to the system?

    I know you have a lot of working hours designing the system, so I didn’t want to just guess. - I thought that if I supplemented my pi4 + RSP1A + (real) cavity filter station with a GPS, and I have some interoperability with the NTPD and GPSD daemons, the solution may not be too far away...
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