preps
Results 1 to 7 of 7

Thread: Three diode negative peak limiter

  1. #1
    Join Date
    Nov 2011
    Location
    North NJ
    Posts
    561
    Thanks
    13
    Thanked 399 Times in 108 Posts
    Downloads
    166
    Uploads
    829

    My Social Networking

    Follow doughboy On Twitter Add doughboy on Facebook
    Visit doughboy's Youtube Channel

    Three diode negative peak limiter

    Peak limiter for plate modulated rigs
    Background

    The three diode limter circuit below uses a keep-alive circuit instead of a tapped resistor, as in other negative peak limiter cicuits. This circuit provides a more constant load to the modulators and produces less distortion than other circuits.
    Circuit Details
    R1 = Plate Impedance of the RF Amplifier, power rating equals 1/20 of the modulator power.
    C1 = 20-40 uF. C1 is not needed if the keep-alive power supply has a similar cap on its output.
    Keep-alive power supply = 1/10 to 1/20 the B+ voltage, e.g. B+ = 1000 V, Keep-alive = 50 V. Current requirement is about 1/10 the current rating of the B+ supply.
    D1 and D3 voltage ratings should be at least four times the B+ Voltage for a good safety factor. D1 and D3 current ratings are about 1/10 the DC plate current of the RF final amplifier.
    D2 voltage ratings should be at least the B+ Voltage (preferably higher). D2 current rating should be three times the DC plate current of the RF final amplifier.
    Maximum negative modulation is controlled by the Keep-alive power supply voltage. The voltage level should be made variable with a variac or suitable sized rheostat.

    Name:  3diodeka.jpg
Views: 484
Size:  12.8 KB




  2. The Following User Says Thank You to doughboy For This Useful Post:

    rainmakersrepair (02-10-2016)

  3. #2
    Join Date
    Dec 2011
    Location
    nj
    Posts
    26
    Thanks
    6
    Thanked 10 Times in 4 Posts
    Downloads
    0
    Uploads
    0
    Like anyone on this forum is going to know what to do with this information. LOL.

  4. #3
    Join Date
    Nov 2011
    Location
    in the planet
    Posts
    628
    Thanks
    185
    Thanked 206 Times in 102 Posts
    Downloads
    10
    Uploads
    0
    awsome Doughboy !! you explained the Three diode negative peak limiter circuit very easy . thank you so much .

  5. #4
    Join Date
    Feb 2016
    Posts
    4
    Thanks
    2
    Thanked 0 Times in 0 Posts
    Downloads
    0
    Uploads
    0
    Quote Originally Posted by doughboy View Post
    Peak limiter for plate modulated rigs
    Background

    The three diode limter circuit below uses a keep-alive circuit instead of a tapped resistor, as in other negative peak limiter cicuits. This circuit provides a more constant load to the modulators and produces less distortion than other circuits.
    Circuit Details
    R1 = Plate Impedance of the RF Amplifier, power rating equals 1/20 of the modulator power.
    C1 = 20-40 uF. C1 is not needed if the keep-alive power supply has a similar cap on its output.
    Keep-alive power supply = 1/10 to 1/20 the B+ voltage, e.g. B+ = 1000 V, Keep-alive = 50 V. Current requirement is about 1/10 the current rating of the B+ supply.
    D1 and D3 voltage ratings should be at least four times the B+ Voltage for a good safety factor. D1 and D3 current ratings are about 1/10 the DC plate current of the RF final amplifier.
    D2 voltage ratings should be at least the B+ Voltage (preferably higher). D2 current rating should be three times the DC plate current of the RF final amplifier.
    Maximum negative modulation is controlled by the Keep-alive power supply voltage. The voltage level should be made variable with a variac or suitable sized rheostat.

    Name:  3diodeka.jpg
Views: 484
Size:  12.8 KB



    So are you using the circuit for a direct inject on like a cobra 29?

    Sent from my SCH-I605 using Tapatalk

  6. #5
    Join Date
    Nov 2011
    Location
    North NJ
    Posts
    561
    Thanks
    13
    Thanked 399 Times in 108 Posts
    Downloads
    166
    Uploads
    829

    My Social Networking

    Follow doughboy On Twitter Add doughboy on Facebook
    Visit doughboy's Youtube Channel
    This is for old tube rigs

  7. The Following User Says Thank You to doughboy For This Useful Post:

    ARCHBISHOP (02-17-2016)

  8. #6
    Join Date
    May 2014
    Location
    BACK STREETS OF OMAHA NEBRASAKA
    Posts
    14
    Thanks
    10
    Thanked 5 Times in 5 Posts
    Downloads
    0
    Uploads
    0
    Thanks Doughboy there are a few vintage plate modulated rigs out there still in service. Plate modulated rigs CB or ham is the best way to in my humble opinion unless you go Flex or Anan with a broadcast processor and a big linear

  9. #7
    Join Date
    May 2021
    Location
    🤨
    Posts
    1
    Thanks
    0
    Thanked 0 Times in 0 Posts
    Downloads
    0
    Uploads
    0
    ������ dayyyuum ittt

Visitors found this page by searching for

negative peak limiter

peak limiter schematic

3-diode peak limiter cobra 29

negitive peak limitersthree diode negative-peak limiterfatboy cb amp reviewsam negative peak limiternj fatboy amp for salecobra 29 negative peakhomemade negative peak limitercobra 29 negative peak limiternegative peak limmiting am peak limiter homemadepower amplifier peak limiternegative diode limitersnegative peak limiter schematicdiode modulation in cobra 29Dioden Limiter cb explain cb modulation limiter circuitcobra 29 modulation limiterthe voltage diode limiter on cb radios locationcobra 29 safety diode locationnegative peal limiter for AM Modulationmodulation limiter diodepeak limiter circuit

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •