Re: si5351a CLK drive levels in uBITX #ubitx
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Michael and all,
I set my signal generator to .5 microvolt @ 7.000 MHz and listened to the sound of it (no accurate S meter here yet). Compiled my own group's software, Version 6.00R (for the BITeensio card we sell) at 6 and 8 ma. 6 ma gave an increase in sensitivity by a noticeable amount (not a lot but noticeable) and 8 ma brought it up again by a quite small amount but I noticed a marked increase in extra signal artifacts in the RX Audio. There were a few added artifiacts @ 6 ma also, but not nearly as pronounced as with the drive set to 8 ma.
This may very well be different for each different uBITX due to the variable nature of the transistors and mixer diode arrays used in the rig. Not a scientific measurement but I did see some RX gain from setting it to 8 ma. I left mine at that setting for now and will run it for a while to see what happens. Might have to get the adapter out and see what it did on TX to the spurious and harmonic output. I don't TX with this particular uBITX except into a dummy load so may let someone with better test equipment check the TX spurs & harmonics @ 8 ma clock drive.
Jim Sheldon, W0EB
------ Original Message ------
From: "Michael Babineau" <mbabineau.ve3wmb@...>
Sent: 7/24/2018 10:27:01 AM
Subject: [BITX20] si5351a CLK drive levels in uBITX #ubitx
I noticed that in both Ashar and Ian's uBITX code that the CLK outputs of the si5351a are being set to 4ma.