Re: ubitx - stop press

Jerry Gaffke
 

Building for myself, I'd try leaving the extra filters out.  Use an EFHW wire with a tuned impedance matching circuit.  Though if mass produced, it really needs an output filter at the amp.  Perhaps some holes in the board for either one band's worth of L"s and C's,  or put socket pins into those holes and use plug-in filter boards.  Can short across those holes with wires and use an external board with relays for a half dozen bands worth of filters, sell that as an option.  Not too surprising, doubt anybody in the last 70 years has sold something that relies on such balance in a push-pull amp. 

I really have to build a basic spectrum analyzer.   Perhaps just an Si5351 breakout board, a 50mhz lowpass filter, a level 7 mixer, a PX1002 86.85mhz SAW filter, an MMIC gain stage, and an AD8310 into a Nano's ADC.    Or do I need more gain stages for this to be useful?  The PJRC 3.2 ARM has a 16 bit SAR ADC, maybe add a second mixer stage to create audio in the 20 to 50 khz range and analyze that in the ARM using DSP techniques.

Jerry, KE7ER


On Fri, Apr 7, 2017 at 09:59 pm, Ashhar Farhan wrote:

1. good news : the homebrew specan does a better job than the rigol.

 

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