Great idea solder leads to the SMD Larry!
steve
> On Oct 22, 2020, at 11:08 AM, Larry <larry@w7iuv.com> wrote:
>
> FYI, since the genuine 2N5109 is so difficult to source (and the 2N3866), you
> might want to look at using a DCP68. This is a surface mount device that will
> electrically replace the 2N5109 in the W7IUV preamp provided you don't need
> to operate it at frequencies higher than 3 Mhz.
>
> I have successfully used this device by simply soldering short leads on the
> part and installing it directly in place of the 2N5109. You do need to
> provide a heat sink of some sort. I have soldered the collector pad down to a
> 3/4 inch square pad on an PCB and have also just soldered a 3/4 inch square,
> or larger, piece of copper sheet directly to the collector tab.
>
> The measured NF at 137 kHz and 475kHz is about 1 dB better than the 5109 and
> about 0.5 dB better on 1.8 Mhz. Best of all is that it costs less than a buck
> and is available from most common distributors.
>
> 73,
>
> Larry - W7IUV
>
>
>
>
>
> On 10/22/2020 9:22 AM, Edward stallman wrote:
>> I remember about a year ago a discussion not to buy the 2n5109 transistors
>> from E-Bay sellers . Some searching shows the 2n5109 has been discontinued
>> for many years . So is anyone that's been saving one for many years willing
>> to part with it ? I'm using it in a W7IUV pre-amp .
>> Thanks Ed N5DG
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