Hi Rick,
Yes, the 2N5109s are almost un-obtainium now, but a few months ago Mouser
stocked them and maybe DigiKey, but now they are out-of-stock. Even the 2N3866
substitute is hard to find.
Over the years (2 decades) I have built at least 10 of these amps, and still
have a supply of a dozen or so 2N5109 devices, and since these devices are
almost indestructible, I’ll likely never run out! You are correct that this is
a problem with this design.
Thanks for the E-field amp link….nice…perhaps another project to build!
I like KiCad a lot. super easy to learn. I had never use a PC board program,
but I was able to learn KiCad from scratch in one evening!
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
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