Re: D4D mods
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I would remove the diode in series with the 5V to the SA602. The minimum operating voltage for the SA602 is 4.5V and performance degrades quickly below 4.5V.
Thank you, Steve. Your diode mod is effective. In my test, the carrier leakage improved by about 5 dB, as a side effect, both USB and LSB signals increased about 1 dB which is a surprise to me. I also applied the BH4DCL diode mod, and it improved the carrier leakage further for another 3 dB, and there was no noticeable difference on the USB and LSB signal level.
I did try to change the emitter resistor from 1.5k to half and it won't help too much, so I will not change it.
So, my recommendation is that we apply both diode mods, hihi.
On Wed, Jul 31, 2019 at 4:36 AM Steven Weber <steve.kd1jv@...> wrote: