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Re: Power output on 20 meters.

 

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Hi DL3HRT, your name would be good. So why take 1 turn from L1 and L2 but not L3, L3 is part of the LPF also, just curious. I would think that if L2 is high in inductance and attenuating the output that L3 would be the same. I have the same low output on my 20 meter QCX, (1.6 watts), so I would like a more definitive solution to figure out exactly what to do as I don¡¯t want to hack my board up experimenting with different things. Thanks for your help.

Joel?
N6ALT

On Nov 1, 2017, at 2:37 AM, DL3HRT <dl3hrt@...> wrote:

Hi all,

I did some optimization on the low pass filter. Finally I had to remove 1 turn from L2 and 1 turn from L3. Power output is as expected now.

I recorded some thermal images with my Seek Reveal Pro. The QCX was running in WSPR-beacon mode with almost continuous transmission. The BS170 heated up to almost 100¡ãC. I think that is safe without heatsink.
<DL3HRT _ BS170 heating.PNG>

<DL3HRT _ 20m_QCX _ output power.png>

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