After playing with a Bullseye LNB for a few days, and discovering that it can be quite easily through a single-wire serial protocol (details at https://raw.githubusercontent.…Alignment%20Procedure.pdf), I wondered how wide the reference oscillator's tuning range is - because that's not specifified in the PDF. And, as they say (quoted from the manual):
There are obviously commands to overwrite and setup the user calibration and issuing these will invalidate any warranty to spec. There is no reason to ever change these constants as the internal algorithms will be impacted corrupting stability and temperature dependance and once changed cannot be recovered, so please don’t fire random commands at the LNB in an event to play around with them you are likely only going to brick the device. We record all values referenced to serial numbers so if units are returned we will know they have been overwritten and the LNB will be recycled and not returned so be warned...
So... "there are obviously commands to overwrite this and that" .. umm .. does anyone here know a bit more than the PDF linked above reveals ?
There are commands to increment / decrement the LNB's LO frequency, but they don't reveal if that controls the 25 MHz TCXO itself, or if it controls a synthesizer between the TCXO and the LO itself. Wild guess: If that's really a programmable synthesizer inside, how far can its frequency be modified ?
An "adjustable TXCO" itself certainly cannot be pulled that far.
Dreaming about reprogramming the Bullseye from the usual 739.x MHz IF to something in the 432 MHz range for /p operation without a PC ... but of course I don't want to "brick" it, despite the low price.
Wolf DL4YHF .