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10510Re: [loopantennas] Trask Amplifier for Wideband Active Loop Amp - mod suggestions?

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  • Chris Trask
    Feb 21, 2014
      >Well, my bulk buy of BC549C's has arrived, so one more question before I get started on the amplifier...
      >How closely do I need to match the transistor pairs? Can I just go by HFE reading on my cheap digital multimeter, or for best results do I need to break out something a bit more serious? If so, what exactly? :)
      >Can I just use my 8405A and check that there's exactly 180 deg phase and equal amplitude on each side?

      I never did go to the trouble of determining if hfe imbslance affected the performance, and it's less important for common base amplifiers than it is for common emitter. But, my feeling is that a match of 5% or less would be prudent.

      Chris Trask
      N7ZWY / WDX3HLB
      Senior Member IEEE
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