Topband: 9 circle RX array combiner board

[Larry]

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
> _________________
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