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Balanced Antenna Amplifiers

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  • Chris Trask
    About a year ago we had a lengthy discussion about active antenna amplifiers, and someone posted a URL for a balanced amplifier that had a pair of JFETs
    Message 1 of 21 , Oct 1, 2007
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      About a year ago we had a lengthy discussion about active antenna
      amplifiers, and someone posted a URL for a balanced amplifier that had a
      pair of JFETs followed by a pair of NPNs. I think it had four varactors for
      tuning. I remember having made a comment about adding a transformer between
      the JFETs and the NPNs to improve the gain and the even-order distortion.
      Somehow, I mananged to misplace that schematic and would like to ask if the
      person who earlier made that avialable would do so again.

      Chris

      ,----------------------. High Performance Mixers and
      / What's all this \ Amplifiers for RF Communications
      / extinct stuff, anyhow? /
      \ _______,--------------' Chris Trask / N7ZWY
      _ |/ Principal Engineer
      oo\ Sonoran Radio Research
      (__)\ _ P.O. Box 25240
      \ \ .' `. Tempe, Arizona 85285-5240
      \ \ / \
      \ '" \ IEEE Senior Member #40274515
      . ( ) \
      '-| )__| :. \ Email: christrask@...
      | | | | \ '. http://www.home.earthlink.net/~christrask
      c__; c__; '-..'>.__

      Graphics by Loek Frederiks
    • Steve Ratzlaff
      Hi Chris, Perhaps Lyle Koehler K0LR s webpage is the one. Scroll down to Balanced Loop Preamp for one circuit similar to your description.
      Message 2 of 21 , Oct 1, 2007
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        Hi Chris,
        Perhaps Lyle Koehler K0LR's webpage is the one. Scroll down to "Balanced
        Loop Preamp" for one circuit similar to your description.
        http://www.mlecmn.net/~lyle/
        Steve
        ----- Original Message -----
        From: "Chris Trask" <christrask@...>
        To: "Loop Antennas" <loopantennas@yahoogroups.com>
        Sent: Monday, October 01, 2007 8:28 AM
        Subject: [loopantennas] Balanced Antenna Amplifiers


        > About a year ago we had a lengthy discussion about active antenna
        > amplifiers, and someone posted a URL for a balanced amplifier that had a
        > pair of JFETs followed by a pair of NPNs. I think it had four varactors
        > for
        > tuning. I remember having made a comment about adding a transformer
        > between
        > the JFETs and the NPNs to improve the gain and the even-order distortion.
        > Somehow, I mananged to misplace that schematic and would like to ask if
        > the
        > person who earlier made that avialable would do so again.
        >
        > Chris
        >
        > ,----------------------. High Performance Mixers and
        > / What's all this \ Amplifiers for RF Communications
        > / extinct stuff, anyhow? /
        > \ _______,--------------' Chris Trask / N7ZWY
        > _ |/ Principal Engineer
        > oo\ Sonoran Radio Research
        > (__)\ _ P.O. Box 25240
        > \ \ .' `. Tempe, Arizona 85285-5240
        > \ \ / \
        > \ '" \ IEEE Senior Member #40274515
        > . ( ) \
        > '-| )__| :. \ Email: christrask@...
        > | | | | \ '. http://www.home.earthlink.net/~christrask
        > c__; c__; '-..'>.__
        >
        > Graphics by Loek Frederiks
        >
        >
        >
        > If you've got links, post them in the Links section!
        > http://groups.yahoo.com/group/loopantennas/links
        >
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      • Chris Trask
        ... Yes, it was the very first schematic in: http://www.mlecmn.net/~lyle/bal-pre/bal-pre.htm Thank you for reminding me. Chris ,----------------------.
        Message 3 of 21 , Oct 1, 2007
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          > Hi Chris,
          > Perhaps Lyle Koehler K0LR's webpage is the one. Scroll down to "Balanced
          > Loop Preamp" for one circuit similar to your description.
          > http://www.mlecmn.net/~lyle/
          > Steve
          >
          > > About a year ago we had a lengthy discussion about active antenna
          > > amplifiers, and someone posted a URL for a balanced amplifier that had a
          > > pair of JFETs followed by a pair of NPNs. I think it had four varactors
          > > for tuning. I remember having made a comment about adding a transformer
          > > between the JFETs and the NPNs to improve the gain and the even-order
          > > distortion. Somehow, I mananged to misplace that schematic and would
          > > like to ask if the person who earlier made that avialable would do so
          > > again.
          > >
          > > Chris
          >

          Yes, it was the very first schematic in:

          http://www.mlecmn.net/~lyle/bal-pre/bal-pre.htm

          Thank you for reminding me.

          Chris

          ,----------------------. High Performance Mixers and
          / What's all this \ Amplifiers for RF Communications
          / extinct stuff, anyhow? /
          \ _______,--------------' Chris Trask / N7ZWY
          _ |/ Principal Engineer
          oo\ Sonoran Radio Research
          (__)\ _ P.O. Box 25240
          \ \ .' `. Tempe, Arizona 85285-5240
          \ \ / \
          \ '" \ IEEE Senior Member #40274515
          . ( ) \
          '-| )__| :. \ Email: christrask@...
          | | | | \ '. http://www.home.earthlink.net/~christrask
          c__; c__; '-..'>.__

          Graphics by Loek Frederiks
        • Chris Trask
          I ve been slowly working on a wideband interference cancelling antenna system, and I have finally gotten around to evaluating the linearity of a number of JFET
          Message 4 of 21 , Nov 19, 2007
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            I've been slowly working on a wideband interference cancelling antenna
            system, and I have finally gotten around to evaluating the linearity of a
            number of JFET devices to be used with an active short dipole array. I've
            posted the results on my webpage at:

            http://www.home.earthlink.net/~christrask/JFET%20Evaluation.pdf

            Chris

            ,----------------------. High Performance Mixers and
            / What's all this \ Amplifiers for RF Communications
            / extinct stuff, anyhow? /
            \ _______,--------------' Chris Trask / N7ZWY
            _ |/ Principal Engineer
            oo\ Sonoran Radio Research
            (__)\ _ P.O. Box 25240
            \ \ .' `. Tempe, Arizona 85285-5240
            \ \ / \
            \ '" \ IEEE Senior Member #40274515
            . ( ) \
            '-| )__| :. \ Email: christrask@...
            | | | | \ '. http://www.home.earthlink.net/~christrask
            c__; c__; '-..'>.__

            Graphics by Loek Frederiks
          • Marc
            ... Does that mean the J309 is a better replacement for the 2sk152 in the Sony 2001D?? http://mywebpages.comcast.net/snarayan/misc/sw/sony2010.html Marc -- --
            Message 5 of 21 , Nov 19, 2007
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              Chris Trask schreef:
              >
              > JFET devices
              > http://www.home.earthlink.net/~christrask/JFET%20Evaluation.pdf
              > <http://www.home.earthlink.net/%7Echristrask/JFET%20Evaluation.pdf>
              >




              Does that mean the J309 is a better replacement for the 2sk152 in the
              Sony 2001D??

              http://mywebpages.comcast.net/snarayan/misc/sw/sony2010.html

              Marc

              --
              --
              Shortwave transmissions in English, Francais, Nederlands, Deutsch, Suid-Afrikaans, Chinese, Dansk, Urdu, Cantonese, Greek, Spanish, Portuguese, ...
              http://shortwave.blogsite.org/ Updated every month or so ...
            • Chris Trask
              ... Not necessarily. I d have to have a couple of those devices to evaluate in order to say. Looking at the datasheet in the 1991 Sony catalogue, the overall
              Message 6 of 21 , Nov 19, 2007
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                > Chris Trask schreef:
                > >
                > > JFET devices
                > > http://www.home.earthlink.net/~christrask/JFET%20Evaluation.pdf
                > > <http://www.home.earthlink.net/%7Echristrask/JFET%20Evaluation.pdf>
                > >
                >
                > Does that mean the J309 is a better replacement for the 2sk152 in the
                > Sony 2001D??
                >
                > http://mywebpages.comcast.net/snarayan/misc/sw/sony2010.html
                >
                > Marc
                >

                Not necessarily. I'd have to have a couple of those devices to evaluate
                in order to say. Looking at the datasheet in the 1991 Sony catalogue, the
                overall linearity is far worse than that of the MPF102 even though it has a
                nicer saturation characteristic, but the gain is very high at 25mS. The
                J309 has a gain of around 15mS, so it might be a usable substitute. The NF
                for the 2SK152 is listed at 1.8dB at 100MHz and for the J309 it's 3.0dB at
                450MHz.

                Chris

                ,----------------------. High Performance Mixers and
                / What's all this \ Amplifiers for RF Communications
                / extinct stuff, anyhow? /
                \ _______,--------------' Chris Trask / N7ZWY
                _ |/ Principal Engineer
                oo\ Sonoran Radio Research
                (__)\ _ P.O. Box 25240
                \ \ .' `. Tempe, Arizona 85285-5240
                \ \ / \
                \ '" \ IEEE Senior Member #40274515
                . ( ) \
                '-| )__| :. \ Email: christrask@...
                | | | | \ '. http://www.home.earthlink.net/~christrask
                c__; c__; '-..'>.__

                Graphics by Loek Frederiks
              • Paul Birke
                very nice detailed information thanks Chris, excellent work Paul V Birke PEng Guelph ON ... From: Chris Trask To:
                Message 7 of 21 , Nov 19, 2007
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                  very nice detailed information

                  thanks Chris, excellent work

                  Paul V Birke PEng
                  Guelph ON


                  ----- Original Message ----
                  From: Chris Trask <christrask@...>
                  To: loopantennas@yahoogroups.com
                  Sent: Monday, November 19, 2007 12:06:23 PM
                  Subject: Re: [loopantennas] Balanced Antenna Amplifiers













                  I've been slowly working on a wideband interference cancelling antenna

                  system, and I have finally gotten around to evaluating the linearity of a

                  number of JFET devices to be used with an active short dipole array. I've

                  posted the results on my webpage at:



                  http://www.home earthlink. net/~christrask/ JFET%20Evaluatio n.pdf



                  Chris



                  ,----------- --------- --. High Performance Mixers and

                  / What's all this \ Amplifiers for RF Communications

                  / extinct stuff, anyhow? /

                  \ _______,---- --------- -' Chris Trask / N7ZWY

                  _ |/ Principal Engineer

                  oo\ Sonoran Radio Research

                  (__)\ _ P.O. Box 25240

                  \ \ .' `. Tempe, Arizona 85285-5240

                  \ \ / \

                  \ '" \ IEEE Senior Member #40274515

                  . ( ) \

                  '-| )__| :. \ Email: christrask@earthlin k.net

                  | | | | \ '. http://www.home earthlink. net/~christrask

                  c__; c__; '-..'>.__



                  Graphics by Loek Frederiks














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                • jr_dakota
                  As always nice work Chris How about a U-310, they are supposed to be better than a J-310 even though they use a similar die, I m curious just how much better
                  Message 8 of 21 , Nov 19, 2007
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                    As always nice work Chris

                    How about a U-310, they are supposed to be better than a J-310 even
                    though they use a similar die, I'm curious just how much better

                    BTW, love that curve tracer ....

                    JR

                    --- In loopantennas@yahoogroups.com, "Chris Trask" <christrask@...> wrote:
                    >
                    > About a year ago we had a lengthy discussion about active antenna
                    > amplifiers, and someone posted a URL for a balanced amplifier that had a
                    > pair of JFETs followed by a pair of NPNs. I think it had four
                    varactors for
                    > tuning. I remember having made a comment about adding a transformer
                    between
                    > the JFETs and the NPNs to improve the gain and the even-order
                    distortion.
                    > Somehow, I mananged to misplace that schematic and would like to ask
                    if the
                    > person who earlier made that avialable would do so again.
                    >
                    > Chris
                    >
                    > ,----------------------. High Performance Mixers and
                    > / What's all this \ Amplifiers for RF Communications
                    > / extinct stuff, anyhow? /
                    > \ _______,--------------' Chris Trask / N7ZWY
                    > _ |/ Principal Engineer
                    > oo\ Sonoran Radio Research
                    > (__)\ _ P.O. Box 25240
                    > \ \ .' `. Tempe, Arizona 85285-5240
                    > \ \ / \
                    > \ '" \ IEEE Senior Member #40274515
                    > . ( ) \
                    > '-| )__| :. \ Email: christrask@...
                    > | | | | \ '. http://www.home.earthlink.net/~christrask
                    > c__; c__; '-..'>.__
                    >
                    > Graphics by Loek Frederiks
                    >
                  • Paul Birke
                    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
                    Message 9 of 21 , Nov 19, 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

                      Also, I notice Dallas Lankford tends to use these U310 JFETs over the J310 JFETs and I don't know why!
                      p

                      ----- Original Message ----
                      From: jr_dakota <SG2112@...>
                      To: loopantennas@yahoogroups.com
                      Sent: Tuesday, November 20, 2007 12:17:01 AM
                      Subject: [loopantennas] Re: Balanced Antenna Amplifiers

















                      How about a U-310, they are supposed to be better than a J-310 even

                      though they use a similar die, I'm curious just how much better











                      [Non-text portions of this message have been removed]
                    • Chris Trask
                      ... Thank you. It was a necessary step in the design process. We had a long discussion on this list earlier this year about various devices and amplifier
                      Message 10 of 21 , Nov 20, 2007
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                        >
                        > As always nice work Chris
                        >

                        Thank you. It was a necessary step in the design process. We had a long discussion on this list earlier this year about various devices and amplifier topologies, so I'm looking at device charateristics.

                        >
                        > How about a U-310, they are supposed to be better than a J-310 even
                        > though they use a similar die, I'm curious just how much better
                        >

                        I'll look and see if I have any. There may be a couple in a packet somewhere.

                        >
                        > BTW, love that curve tracer ....
                        >

                        I bought that for $30 many years ago. By the time I got it to my truck, I fully understood why it has two heavy leather handles on the top. Had to stop and rest twice.




                        Chris

                        ,----------------------. High Performance Mixers and
                        / What's all this \ Amplifiers for RF Communications
                        / extinct stuff, anyhow? /
                        \ _______,--------------' Chris Trask / N7ZWY
                        _ |/ Principal Engineer
                        oo\ Sonoran Radio Research
                        (__)\ _ P.O. Box 25240
                        \ \ .' `. Tempe, Arizona 85285-5240
                        \ \ / \
                        \ '" \ IEEE Senior Member #40274515
                        . ( ) \
                        '-| )__| :. \ Email: christrask@...
                        | | | | \ '. http://www.home.earthlink.net/~christrask
                        c__; c__; '-..'>.__

                        Graphics by Loek Frederiks
                      • Chris Trask
                        ... I looked through the listings of JFET offerings from Philips, Fairchild, and ON Semiconductor, then went to see what was readily available from
                        Message 11 of 21 , 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.




                          Chris

                          ,----------------------. High Performance Mixers and
                          / What's all this \ Amplifiers for RF Communications
                          / extinct stuff, anyhow? /
                          \ _______,--------------' Chris Trask / N7ZWY
                          _ |/ Principal Engineer
                          oo\ Sonoran Radio Research
                          (__)\ _ P.O. Box 25240
                          \ \ .' `. Tempe, Arizona 85285-5240
                          \ \ / \
                          \ '" \ IEEE Senior Member #40274515
                          . ( ) \
                          '-| )__| :. \ Email: christrask@...
                          | | | | \ '. http://www.home.earthlink.net/~christrask
                          c__; c__; '-..'>.__

                          Graphics by Loek Frederiks
                        • mhatlau
                          The reason, as I understand it, is that the U-310 has better linearity at high drain current than the J-310. This results in a higher IM2 and IM3 figures in
                          Message 12 of 21 , Nov 20, 2007
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                            The reason, as I understand it, is that the U-310 has better linearity
                            at high drain current than the J-310. This results in a higher IM2
                            and IM3 figures in the resulting amplifier.

                            --- In loopantennas@yahoogroups.com, Paul Birke <nonlinear@...> wrote:
                            >
                            > 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
                            >
                            > Also, I notice Dallas Lankford tends to use these U310 JFETs over
                            the J310 JFETs and I don't know why!
                            > p
                            >
                            > ----- Original Message ----
                            > From: jr_dakota <SG2112@...>
                            > To: loopantennas@yahoogroups.com
                            > Sent: Tuesday, November 20, 2007 12:17:01 AM
                            > Subject: [loopantennas] Re: Balanced Antenna Amplifiers
                            >
                            >
                            >
                            >
                            >
                            >
                            >
                            >
                            >
                            >
                            >
                            >
                            >
                            >
                            >
                            >
                            >
                            > How about a U-310, they are supposed to be better than a J-310 even
                            >
                            > though they use a similar die, I'm curious just how much better
                            >
                            >
                            >
                            >
                            >
                            >
                            >
                            >
                            >
                            >
                            >
                            > [Non-text portions of this message have been removed]
                            >
                          • Chris Trask
                            ... 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
                            Message 13 of 21 , 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

                              ,----------------------. High Performance Mixers and
                              / What's all this \ Amplifiers for RF Communications
                              / extinct stuff, anyhow? /
                              \ _______,--------------' Chris Trask / N7ZWY
                              _ |/ Principal Engineer
                              oo\ Sonoran Radio Research
                              (__)\ _ P.O. Box 25240
                              \ \ .' `. Tempe, Arizona 85285-5240
                              \ \ / \
                              \ '" \ IEEE Senior Member #40274515
                              . ( ) \
                              '-| )__| :. \ Email: christrask@...
                              | | | | \ '. http://www.home.earthlink.net/~christrask
                              c__; c__; '-..'>.__

                              Graphics by Loek Frederiks
                            • Paul Birke
                              Chris Trask said:== I don t like buying parts from Mouser due to their excessive shipping charges, NO KIDDING! AMS is also guilty of this practice, a big box
                              Message 14 of 21 , Nov 20, 2007
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                                Chris Trask said:==>
                                I don't like buying parts from Mouser due to their excessive shipping charges,



                                NO KIDDING!



                                AMS is also guilty of this practice, a big box with packing for components most others get into a small air mail packet. One way to make money I guess.



                                p









                                [Non-text portions of this message have been removed]
                              • jr_dakota
                                The can take more current and have better IP2 and IP3 specs over the J-310 ... That has been mentioned in numerous sources over the years, one or two of which
                                Message 15 of 21 , Nov 21, 2007
                                • 0 Attachment
                                  The can take more current and have better IP2 and IP3 specs over the
                                  J-310 ... That has been mentioned in numerous sources over the years,
                                  one or two of which Dallas has obviously read ... A couple of
                                  articles/books by Doug Demaw is where I remember first seeing it

                                  I originally built the small whip circuit with a J310 and later put a
                                  U310 in and there was a noticable difference

                                  JR

                                  --- In loopantennas@yahoogroups.com, Paul Birke <nonlinear@...> wrote:
                                  >
                                  > 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
                                  >
                                  > Also, I notice Dallas Lankford tends to use these U310 JFETs over
                                  the J310 JFETs and I don't know why!
                                  > p
                                  >
                                  > ----- Original Message ----
                                  > From: jr_dakota <SG2112@...>
                                  > To: loopantennas@yahoogroups.com
                                  > Sent: Tuesday, November 20, 2007 12:17:01 AM
                                  > Subject: [loopantennas] Re: Balanced Antenna Amplifiers
                                  >
                                  >
                                  >
                                  >
                                  >
                                  >
                                  >
                                  >
                                  >
                                  >
                                  >
                                  >
                                  >
                                  >
                                  >
                                  >
                                  >
                                  > How about a U-310, they are supposed to be better than a J-310 even
                                  >
                                  > though they use a similar die, I'm curious just how much better
                                  >
                                  >
                                  >
                                  >
                                  >
                                  >
                                  >
                                  >
                                  >
                                  >
                                  >
                                  > [Non-text portions of this message have been removed]
                                  >
                                • Chris Trask
                                  ... I was looking at these other devices as I came across something while doing PSpice simulations that needed to be investigated further. The gain of both
                                  Message 16 of 21 , Nov 22, 2007
                                  • 0 Attachment
                                    >
                                    > The can take more current and have better IP2 and IP3
                                    > specs over the J-310 ... That has been mentioned in
                                    > numerous sources over the years, one or two of which
                                    > Dallas has obviously read ... A couple of articles/books
                                    > by Doug Demaw is where I remember first seeing it
                                    >
                                    > I originally built the small whip circuit with a J310
                                    > and later put a U310 in and there was a noticable
                                    > difference
                                    >
                                    >
                                    > --- In loopantennas@yahoogroups.com, Paul Birke <nonlinear@...> wrote:
                                    >
                                    > > 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
                                    > >
                                    > > Also, I notice Dallas Lankford tends to use these U310
                                    > > JFETs over the J310 JFETs and I don't know why!
                                    >

                                    I was looking at these other devices as I came across something while
                                    doing PSpice simulations that needed to be investigated further. The gain
                                    of both the J309 and J310 drops off when Vds drops below 5V, and the
                                    configuration that I chose (a balanced cascode transimpedance amplifier)
                                    requires that the FETs have about 4V Vds. The 2N3819 did not have the gain
                                    drop off at that voltage in the PSpice simulation. Since I did that initial
                                    evaluation, I've found that the 2N4416 has twice the gain of the 2N3819
                                    while having the same parasitic capacitances, so it may be a suitable
                                    choice. A few people on various lists are sending me a few of these to
                                    evaluate. At $3.05 each from Mouser the 2N4416 is pretty expensive, but the
                                    PN4416 costs only a dime so that is a further incentive to evaluate it.

                                    And then there's the BF244A/B/C, the low voltage curves of which look
                                    fairly nice in the datasheet and which has a NF of 1.5dB at 100MHz (15V,
                                    5mA). Those devices are only available from Mouser, so I guess that
                                    sometime soon I'm going to float another parts order with them whether I
                                    like it or not.

                                    Chris

                                    ,----------------------. High Performance Mixers and
                                    / What's all this \ Amplifiers for RF Communications
                                    / extinct stuff, anyhow? /
                                    \ _______,--------------' Chris Trask / N7ZWY
                                    _ |/ Principal Engineer
                                    oo\ Sonoran Radio Research
                                    (__)\ _ P.O. Box 25240
                                    \ \ .' `. Tempe, Arizona 85285-5240
                                    \ \ / \
                                    \ '" \ IEEE Senior Member #40274515
                                    . ( ) \
                                    '-| )__| :. \ Email: christrask@...
                                    | | | | \ '. http://www.home.earthlink.net/~christrask
                                    c__; c__; '-..'>.__

                                    Graphics by Loek Frederiks
                                  • Paul Birke
                                    Dear Chris Dan s Small Parts and Kits have both of these 4416 transistors the 2N4416A for $1.95 and the PN4416 for 3 for $1.25 Dan is at
                                    Message 17 of 21 , Nov 22, 2007
                                    • 0 Attachment
                                      Dear Chris

                                      Dan's Small Parts and Kits have both of these 4416 transistors
                                      the 2N4416A for $1.95 and the PN4416 for 3 for $1.25

                                      Dan is at

                                      http://www.danssmallpartsandkits.net/


                                      try to get more like 6 volts on the J309/J310 if you can
                                      you may have to raise the supply voltage
                                      I would not operate at 4v too close to the knee
                                      very best
                                      Paul

                                      ----- Original Message ----
                                      From: Chris Trask <christrask@...>
                                      To: Loop Antennas <loopantennas@yahoogroups.com>
                                      Sent: Thursday, November 22, 2007 11:14:54 AM
                                      Subject: Re: [loopantennas] Re: Balanced Antenna Amplifiers













                                      >

                                      > The can take more current and have better IP2 and IP3

                                      > specs over the J-310 ... That has been mentioned in

                                      > numerous sources over the years, one or two of which

                                      > Dallas has obviously read ... A couple of articles/books

                                      > by Doug Demaw is where I remember first seeing it

                                      >

                                      > I originally built the small whip circuit with a J310

                                      > and later put a U310 in and there was a noticable

                                      > difference

                                      >

                                      >

                                      > --- In loopantennas@ yahoogroups. com, Paul Birke <nonlinear@. ..> wrote:

                                      >

                                      > > 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

                                      > >

                                      > > Also, I notice Dallas Lankford tends to use these U310

                                      > > JFETs over the J310 JFETs and I don't know why!

                                      >



                                      I was looking at these other devices as I came across something while

                                      doing PSpice simulations that needed to be investigated further. The gain

                                      of both the J309 and J310 drops off when Vds drops below 5V, and the

                                      configuration that I chose (a balanced cascode transimpedance amplifier)

                                      requires that the FETs have about 4V Vds. The 2N3819 did not have the gain

                                      drop off at that voltage in the PSpice simulation. Since I did that initial

                                      evaluation, I've found that the 2N4416 has twice the gain of the 2N3819

                                      while having the same parasitic capacitances, so it may be a suitable

                                      choice. A few people on various lists are sending me a few of these to

                                      evaluate. At $3.05 each from Mouser the 2N4416 is pretty expensive, but the

                                      PN4416 costs only a dime so that is a further incentive to evaluate it.



                                      And then there's the BF244A/B/C, the low voltage curves of which look

                                      fairly nice in the datasheet and which has a NF of 1.5dB at 100MHz (15V,

                                      5mA). Those devices are only available from Mouser, so I guess that

                                      sometime soon I'm going to float another parts order with them whether I

                                      like it or not.



                                      Chris



                                      ,----------- --------- --. High Performance Mixers and

                                      / What's all this \ Amplifiers for RF Communications

                                      / extinct stuff, anyhow? /

                                      \ _______,---- --------- -' Chris Trask / N7ZWY

                                      _ |/ Principal Engineer

                                      oo\ Sonoran Radio Research

                                      (__)\ _ P.O. Box 25240

                                      \ \ .' `. Tempe, Arizona 85285-5240

                                      \ \ / \

                                      \ '" \ IEEE Senior Member #40274515

                                      . ( ) \

                                      '-| )__| :. \ Email: christrask@earthlin k.net

                                      | | | | \ '. http://www.home earthlink. net/~christrask

                                      c__; c__; '-..'>.__



                                      Graphics by Loek Frederiks














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                                      [Non-text portions of this message have been removed]
                                    • Chris Trask
                                      ... Paul, Yes, I saw yesterday evening that Dan had both of those. I picked up 50 pieces of the PN4416 on eBay along with some J309s and J310s to add to my
                                      Message 18 of 21 , Nov 22, 2007
                                      • 0 Attachment
                                        >
                                        > Dan's Small Parts and Kits have both of these 4416 transistors
                                        > the 2N4416A for $1.95 and the PN4416 for 3 for $1.25
                                        >
                                        > Dan is at
                                        >
                                        > http://www.danssmallpartsandkits.net/
                                        >
                                        > try to get more like 6 volts on the J309/J310 if you can
                                        > you may have to raise the supply voltage
                                        > I would not operate at 4v too close to the knee
                                        > very best
                                        >

                                        Paul,
                                        Yes, I saw yesterday evening that Dan had both of those. I picked up 50
                                        pieces of the PN4416 on eBay along with some J309s and J310s to add to my
                                        bench stock. I also want to look at the BF244A/B/C to see how they compare
                                        with these other devices. The datasheet looks good, but I want to take a
                                        close look at the 4V Vds characteristics and see if I can make this
                                        configuration of mine work without going to a higher supply voltage or
                                        doubling the drain current by splitting things up. Nothing is cast in iron
                                        at this point, except that the control head for this interference cancelling
                                        antenna uses a 12V supply, and I need to work with that if at all possible.

                                        In the meantime, I've been sent the schematic for an interesting
                                        military active loop DF antenna that consists of a balanced source follower
                                        using a monolithic matched pair of JFETs that is transformer coupled to a
                                        balanced pair of series/shunt feedback amplifiers using 2N5109s running at
                                        about 100mA each. Those devices are dissipating about 1.5W each, which is
                                        pretty toasty for a TO-5 package.

                                        Chris

                                        ,----------------------. High Performance Mixers and
                                        / What's all this \ Amplifiers for RF Communications
                                        / extinct stuff, anyhow? /
                                        \ _______,--------------' Chris Trask / N7ZWY
                                        _ |/ Principal Engineer
                                        oo\ Sonoran Radio Research
                                        (__)\ _ P.O. Box 25240
                                        \ \ .' `. Tempe, Arizona 85285-5240
                                        \ \ / \
                                        \ '" \ IEEE Senior Member #40274515
                                        . ( ) \
                                        '-| )__| :. \ Email: christrask@...
                                        | | | | \ '. http://www.home.earthlink.net/~christrask
                                        c__; c__; '-..'>.__

                                        Graphics by Loek Frederiks
                                      • Chris Trask
                                        ... I may have to take back what I said about Mouser s shipping charges. I placed an order with them over the weekend for some BF244A/B/C JFETs for this
                                        Message 19 of 21 , Nov 26, 2007
                                        • 0 Attachment
                                          >
                                          > Chris Trask said:==>
                                          > > I don't like buying parts from Mouser due to their excessive
                                          > > shipping charges,
                                          >
                                          >
                                          > NO KIDDING!
                                          >
                                          >
                                          > AMS is also guilty of this practice, a big box with packing for
                                          > components most others get into a small air mail packet. One
                                          > way to make money I guess.
                                          >
                                          >

                                          I may have to take back what I said about Mouser's shipping charges. I
                                          placed an order with them over the weekend for some BF244A/B/C JFETs for
                                          this evaluation project along with some other parts, choosing UPS ground to
                                          save on the shipping. They upgraded it to 2nd day air at their expense, so
                                          I only get charged for the UPS ground and they assume the extra $7 for the
                                          upgrade.

                                          I am impressed. I guess Christmas came early this year.

                                          Chris

                                          ,----------------------. High Performance Mixers and
                                          / What's all this \ Amplifiers for RF Communications
                                          / extinct stuff, anyhow? /
                                          \ _______,--------------' Chris Trask / N7ZWY
                                          _ |/ Principal Engineer
                                          oo\ Sonoran Radio Research
                                          (__)\ _ P.O. Box 25240
                                          \ \ .' `. Tempe, Arizona 85285-5240
                                          \ \ / \
                                          \ '" \ IEEE Senior Member #40274515
                                          . ( ) \
                                          '-| )__| :. \ Email: christrask@...
                                          | | | | \ '. http://www.home.earthlink.net/~christrask
                                          c__; c__; '-..'>.__

                                          Graphics by Loek Frederiks
                                        • Paul Birke
                                          that sound better Chris-good to know but my comments on AMS stands just plain hurts the so-called brokerage fees to Canada Paul ... From: Chris Trask
                                          Message 20 of 21 , Nov 26, 2007
                                          • 0 Attachment
                                            that sound better Chris-good to know

                                            but my comments on AMS stands

                                            just plain hurts the so-called brokerage fees to Canada

                                            Paul

                                            ----- Original Message ----
                                            From: Chris Trask <christrask@...>
                                            To: loopantennas@yahoogroups.com
                                            Sent: Monday, November 26, 2007 10:15:12 PM
                                            Subject: Re: [loopantennas] Re: Balanced Antenna Amplifiers













                                            >

                                            > Chris Trask said:==>

                                            > > I don't like buying parts from Mouser due to their excessive

                                            > > shipping charges,

                                            >

                                            >

                                            > NO KIDDING!

                                            >

                                            >

                                            > AMS is also guilty of this practice, a big box with packing for

                                            > components most others get into a small air mail packet. One

                                            > way to make money I guess.

                                            >

                                            >



                                            I may have to take back what I said about Mouser's shipping charges. I

                                            placed an order with them over the weekend for some BF244A/B/C JFETs for

                                            this evaluation project along with some other parts, choosing UPS ground to

                                            save on the shipping. They upgraded it to 2nd day air at their expense, so

                                            I only get charged for the UPS ground and they assume the extra $7 for the

                                            upgrade.



                                            I am impressed. I guess Christmas came early this year.



                                            Chris



                                            ,----------- --------- --. High Performance Mixers and

                                            / What's all this \ Amplifiers for RF Communications

                                            / extinct stuff, anyhow? /

                                            \ _______,---- --------- -' Chris Trask / N7ZWY

                                            _ |/ Principal Engineer

                                            oo\ Sonoran Radio Research

                                            (__)\ _ P.O. Box 25240

                                            \ \ .' `. Tempe, Arizona 85285-5240

                                            \ \ / \

                                            \ '" \ IEEE Senior Member #40274515

                                            . ( ) \

                                            '-| )__| :. \ Email: christrask@earthlin k.net

                                            | | | | \ '. http://www.home earthlink. net/~christrask

                                            c__; c__; '-..'>.__



                                            Graphics by Loek Frederiks














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                                            [Non-text portions of this message have been removed]
                                          • Chris Trask
                                            ... I have rewritten the JFET evaluation that I posted earlier this month, more than doubling the number of devices evaluated and with some morte extensive
                                            Message 21 of 21 , Nov 30, 2007
                                            • 0 Attachment
                                              >
                                              > 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
                                              >
                                              > Also, I notice Dallas Lankford tends to use these U310
                                              > JFETs over the J310 JFETs and I don't know why!
                                              >

                                              I have rewritten the JFET evaluation that I posted earlier this month,
                                              more than doubling the number of devices evaluated and with some morte
                                              extensive commentary:

                                              http://www.home.earthlink.net/~christrask/JFET%20Evaluation.pdf

                                              I was fortunate in obrtaining a number of 2N4416's for this exercise, as
                                              well as a single U310 in a TO-18 package. That's a curious device, as the
                                              gate is connected to the case. Not at all surprising, as that entire family
                                              of devices was very popular as common-gate amplifiers for CATV applications.

                                              Chris

                                              ,----------------------. High Performance Mixers and
                                              / What's all this \ Amplifiers for RF Communications
                                              / extinct stuff, anyhow? /
                                              \ _______,--------------' Chris Trask / N7ZWY
                                              _ |/ Principal Engineer
                                              oo\ Sonoran Radio Research
                                              (__)\ _ P.O. Box 25240
                                              \ \ .' `. Tempe, Arizona 85285-5240
                                              \ \ / \
                                              \ '" \ IEEE Senior Member #40274515
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                                              c__; c__; '-..'>.__

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