Topband: Looking for a 2n5109

[VE6WZ_Steve]

Great idea solder leads to the SMD Larry!

steve
> On Oct 22, 2020, at 11:08 AM, Larry <larry at 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
>> _________________
>> Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
> _________________
> Searchable Archives: http://www.contesting.com/_topband - Topband Reflector