[hpsdr] MRFE6VP61K25H Amps

[jeff millar]

On 09/22/2011 12:57 AM, lstoskopf at cox.net wrote:
> ***** High Performance Software Defined Radio Discussion List *****
>
> Thanks for the replies on my post.  I hadn't realized how robust the 50 V supplies were on voltage regulation.
>
> As for RF/DC current through the heat sinks, there has been considerable discussion on another list about voids when soldering to a heat sink and thermal failure from a bad solder job.  Thus some recommendation that you use thermal paste.  I'm not sure the current conductivity through the paste.  The rugged devices seem more likely to fail from bad heat dissipation than SWR unless the heat conductivity is at fault.  I picked up an EK-Supreme HF heatsink a few weeks ago that will easily handle the heat and has a clean and highly polished interface surface.  My thought is to blow nitrogen into the convection oven I for the usual reasons.  Now a bit more thought on that 100 Amps.
>
> My one gripe with the manufacturer is a lack of full load output and input matching impedances.  The give Smith charts of sorts and those values for 230 MHz.  My request for more info let to a 'we'll get back to you' answer.
They do have full impedance characterization in the S-parameter file downloads.  
I took that file, loaded it into "qucs", a free RF circuit simulator and 
developed some conceptual output network designs.  If you're not familiar with 
qucs, it's well worth climbing the learning curve.

"qucs" is sorta SDR in the sense that it can model many aspects of the rf (and 
digital) design on the computer.

jeff, wa1hco
> Will get back on this project when the snow flies.  Meanwhile will let this list get back to HPSDR!
>
> N0UU
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