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
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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
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