Topband: 9 circle RX array combiner board

[Mike Waters]

Mouser is going to have over 4600 Central Semiconductor 2N5109 BJTs at the
end of this month. :-)

https://www.mouser.com/ProductDetail/Central-Semiconductor/2N5109?qs=sGAEpiMZZMshyDBzk1%2FWiw99kSkYzPxmkl%252BSQJuBJrk%3D

73, Mike
W0BTU

On Sun, Mar 1, 2020, 5:55 PM Larry <larry at w7iuv.com> wrote:

> RE: 2N5109 replacement
>
> With my supply of 2N5109's getting low, I looked long and hard at
> suitable replacement parts.
>
> There just isn't anything made in a leaded package that's worth while.
>
> I did find a rather generic power transistor in a "large" SMD package
> that works quite well in my preamps for the MF and LF ranges.
>
> The DCP68 (and for those who need a PNP DCP69) has proven to be somewhat
> better than the 5109 in this application with a measured NF averaging
> 4.5 dB vs. the 5.5 dB of the 5109.
>
> I have, in fact, soldered pigtails on the SMD part and stuck it in place
> of the 5109 on existing boards (with suitable heat sink).
>
> I'm happy with the part but of course YMMV!
>
> 73,
>
> Larry - W7IUV
>
>
> On 3/1/2020 3:31 PM, Richard (Rick) Karlquist wrote:
> >
> >
> > On 3/1/2020 2:22 PM, VE6WZ_Steve wrote:
> >> Just like some guys enjoy woodworking and making furniture that they
> >> may not really need, I like to build radio things just for the fun of
> >> the project even though I may not really “need” it.  For three years I
> >> have been using the original 9 circle RX array kit that I bought from
> >> DX-engineering, and it has performed well, but I wanted to build my
> >> own and add my own design tweaks.
> >>
> >> Using KiCad, I have designed and built a 9 circle RX array combiner
> >> with a 2N5109 pre-amplifier integrated onto the same board.
> >>
> >
> >> 73, de steve ve6wz
> >> _________________
> >>
> >
> > Now I know why you work stuff I can't even hear :-)
> >
> > The 2N5109 is just about extinct.  Did you secure a
> > source for it before you laid out your PC board?  If
> > you did, please share it with the rest of us.  Most
> > people are now using substitutes for the 2N5109 with
> > varying degrees of success.  Are you possibly doing
> > that?  Of course those substitutes are not in a
> > hermetic metal can, so the PC board has to be laid
> > out for differently for them.
> >
> > You might want to look at these references for
> > so-called "E-field" arrays of whip antennas:
> >
> > A military design:
> >
> >
> https://www.dst.defence.gov.au/sites/default/files/publications/documents/DST-Group-TR-3522.pdf
> >
> >
> > Various improvements to the above:
> >
> >
> http://home.earthlink.net/~christrask/Complementary%20Push-Pull%20Amplifiers.pdf
> >
> >
> > You also find a lot of other good stuff on Chris's site.
> >
> > They go beyond the DXE design.
> >
> > Good luck with your project.
> >
> > BTW, how do you like KICAD?  I'm currently using a grandfathered
> > EAGLE 7.7 perpetual license, but "some day" I might switch to KICAD.
> >
> > 73
> > Rick N6RK
> > _________________
> > Searchable Archives: http://www.contesting.com/_topband - Topband
> Reflector
> _________________
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> Reflector
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