Re: 5W Power Amp and the U3S; Options for a few watts


K2DB Paul Mackanos
 

Andrew, to answer your question I don’t have a clue, as I have not finished the entire project and then closed it and ran it yet 🤓
Paul K2DB

On Wed, Apr 15, 2020 at 6:29 AM Andrew Lenton <a@...> wrote:

I tried this configuration, and found by mounting the 5Watt amp inside the case, the whole unit got far too hot, even with fans, so built my own PA dead bug style in the bottom of the case, which produced 15 Watts! on 40m, using a BF035 UHF RF power transistor, this ran for months until the BS170 died for no good reason, it was running on 5V perhaps it did not like the match into the power transistor? It is all stripped out now and back to 135mW ish.

 

My question how hot does your 2-5 Watt unit get when using WSPR with its 2 minute transmitting period?

 

73

 

Andrew

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