[MRCA] grc109 r1004 receiver ebay dc dc converter

[Robert Nickels]

On 12/28/2024 6:34 AM, JEFF CICCONE via MRCA wrote:
> folks. looking at using this epay chinesium dc dc converter for 
> portable operation.  does anyone have experience with using these as 
> far as quality, receiver noise, etc 

I haven't used that particular one but like most, the seller doesn't 
have a clue and the specs are nonsense.  No way will you ever get 900 
watts out of that thing.    In general,  you can have something near the 
specified voltage but not at the specified current or power.  Even his 
own load tester shows 142 watts output and I wouldn't want t put my 
finger on the heatsink at that level for very long!   The only way to 
know what it's capable of is to buy one and test it or find someone else 
who knows their stuff that has done so.

The more common type can be found by searching "ZVS  45-390V" - they are 
now selling for < $5 shipped and work well as long as you derate them 
and provide sufficient filtering/shielding for your application.   The 
schematic of this design is also available as are replacement parts  and 
it's been around long enough to have become a "standard" that is 
available from numerous sellers.   The switching frequency is 75 kHz and 
I run the output voltage no higher than 300V, where they will supply up 
to 20 watts.   Be sure to bypass the supply leads if you're using them 
to run a transmitter as RF will definitely kill the controller IC.

73, Bob W9RAN
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.qth.net/pipermail/mrca/attachments/20241228/b85c3143/attachment-0001.html>