[hpsdr] MRFE6VP61K25H Amps

[jeff millar]

On 09/21/2011 06:12 PM, lstoskopf at cox.net wrote:
> ***** High Performance Software Defined Radio Discussion List *****
>
> I've been waiting on the 6M only version of the 2M one presented last year in DUBUS.  With the new bullet proof version I can't see any reason why this device or a competing device shouldn't be the amp of the future for QRO.  It can be driven by what we already have.  Surplus (new) 50v. power modules are readily available on eBay.  I'm guessing that some extra DC filter/storage might be needed as these supplies probably are intended on a steady load, not SSB.
We used a dual MRFE6VP61 amp on two meters from a single HP 226519 power supply 
(50V, 57Amps) and except for grounding the return line and adding some RF noise 
reduction capacitors across the output leads, it worked perfectly without any 
other changes.

If you consider a computer server farm that is the native load for this power 
supplies, they can switch from low power idle to 100% CPU load in microseconds, 
so the supplies have to deal with large, fast load transients.
> You could almost make separate amps for 160, 6, and then the rest of the bands for little money.
>
> I'm thinking that my 160M 6M and 2M  versions will be water cooled using sinks from the PC industry and all mounted in one MacPC case.
Agreed, the best heat sink data shows a thermal resistance of 0.03 degree C per 
Watt with about 1.5 gallons per minute water flow.  The commercial heat sinks 
are very nice, perfectly smooth and polished.  But I've been thinking about how 
to tie the heat sink into the input and output network ground plane.  The 
transistor heat sink flange and the mated cooler has to handle the RF return 
currents for 1250W at about 1.5 Ohms impedance...that's upwards of 1000 Amps.

jeff, wa1hco
> N0UU


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