Re: uBITx v5 - with mods
Ravi,toggle quoted messageShow quoted text
Your equations look correct, though this might be a more concise description of the math involved:
That was for a uBitx-v3, so had the 12mhz IF crystals, not 11.052mhz.
Those IF crystals get sorted at hfsignals into bins by frequency such that all crystals
used in any given rig are of the same frequency within perhaps 100hz or better.
Between rigs using crystals from different sorting bins, the 12mhz (or 11.0592mhz)
crystal filter can vary from rig to rig by a khz or so.
Some have found that the rig sounds better if the BFO is moved away
from its factory value by a few hundred hz.
Likewise, the center frequency of 45mhz filter might vary by a few khz,
but it is wide enough that you probably would not notice any reduced sensitivity
or change in audio quality without a direct A/B test.
An RF preamp may be needed to hear much if operating with a short whip.
Several here have played with different si5351 output drive levels and came to
different conclusions. This can affect signal levels and birdies, but generally isn't critical.
The ideal settings might vary a bit from rig to rig, and your local incoming RF levels.
Posts 35235 and 54501 describe a calibration procedure that might be of interest.
On Mon, Jun 10, 2019 at 06:09 AM, Ravi Miranda wrote:
Hi Sarma, Farhan, Curt,