Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

RF Pre-Amp Protection

  1. Feb 1, 2016 #1
    I have these great Mini-Circuits amplifier modules (ZFL-1000LN+) I use all the time that keep getting blown by a nearby HAM radio operator. Can I protect the input to this module by soldering two anti-parallel fast switching diodes from the input connection to ground?
     
  2. jcsd
  3. Feb 1, 2016 #2

    Averagesupernova

    User Avatar
    Science Advisor
    Gold Member

    I doubt that you are frying this thing from a nearby ham. You realize that hams would use this sort of device on their own receivers which would have to take much more when it is next to the transmitter than in your situation. Unless you are the ham, you are not closer than that. It takes over 2 milliwatts to do it according to specs. You sure it isn't ESD or something? What's the application? Diodes right out on an antenna is a bad idea concerning generating more interference.
     
  4. Feb 1, 2016 #3

    berkeman

    User Avatar

    Staff: Mentor

    What frequencies are you using in your setup? What is connected to the input and output of your amp? Do you know what band the HAM is transmitting on, and what power they are transmitting?
     
  5. Feb 1, 2016 #4

    berkeman

    User Avatar

    Staff: Mentor

  6. Feb 1, 2016 #5

    sophiecentaur

    User Avatar
    Science Advisor
    Gold Member

    You could always put a good RF choke in your power supply lead and/or your signal input.
    Good decoupling on your power rails could also help.
    I you know who he/she is, you could tell him he's almost certainly breaking the regs.
     
  7. Feb 1, 2016 #6

    Averagesupernova

    User Avatar
    Science Advisor
    Gold Member

    By what evidence? All we know is there is a ham in the neighborhood, and some guy has mixers amplifiers failing.
     
    Last edited: Feb 1, 2016
  8. Feb 1, 2016 #7

    sophiecentaur

    User Avatar
    Science Advisor
    Gold Member

    That's a far too reasonable atitude! :wink: Why not sow a bit of discord when the opportunity arises?
    Of course, the 'interference' would not be continuous from a Ham - just in bursts :"CQ DX CQ DX!!!" and the like.
    A log of the times of interference would soon prove or disprove the theory.
     
  9. Feb 1, 2016 #8

    Averagesupernova

    User Avatar
    Science Advisor
    Gold Member

    Correct! We don't know what band this amp is working in nor do we know if there is any selectivity ahead of it. I.E., an antenna that is tuned to the proper band. Hard to believe front end overload would fry an amp with this spec.
     
  10. Feb 2, 2016 #9

    sophiecentaur

    User Avatar
    Science Advisor
    Gold Member

    If that happened to me, I'd put it down to 'cock up rather than conspiracy'.
    'Frying' a component sounds like wiring it up wrong. That's always a possibility (with me, at least).
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: RF Pre-Amp Protection
  1. RF Amplifers vs. Op Amps (Replies: 12)

Loading...