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4273Re: [loopantennas] Re: Balanced Antenna Amplifiers

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  • Chris Trask
    Nov 20, 2007
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      >
      > >
      > > the noise is slightly better with the U310 but only slightly
      > > than the J310h at 450 MHz the delta is about 0.3 dB
      > > nothing to write home about!
      > > Chris may know other variables that could be better
      > >
      >
      > I looked through the listings of JFET offerings from Philips,
      > Fairchild, and ON Semiconductor, then went to see what was
      > readily available from distributors, eBay, Dan, and others. All
      > I could come up with was those five devices. Too bad single
      > gate MOSFETs aren't readily available.
      >

      I don't have any U310's here, and looking through an older Siliconix
      databook shows that it and the J310 and the SST310 are all made from the
      same die, so I doubt that there would be any real difference. But, looking
      through the rest of that databook I came across the 2N4416. This device has
      about half of the lumped model capacitances and a slightly higher NF than
      the J310. The curve family and tabulated data shows that it's basically a
      higher gain version of the 2N3819, so it might be worth evaluating to see
      how well it compares to the J309 as the 2N3819 came in second. It must be
      fairly good as Mouser gets $2.24 each for these. I don't like buying parts
      from Mouser due to their excessive shipping charges, so I'll have to see if
      I can get one or two from someone on one of the list servers.


      Chris

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