Posts by DG9BFC

    the ast3tq does not work with 1.8v i guess (it is a 3.3v unit) and there is NO CLEAN 3.3v insidfe the pluto

    but you can now get 40 megs 1.8v with 0.5 ppm from epson

    TG2520SMN 40.0000M-ECGNNM


    the astx13/asvrtx13 is now out of stock but the epson works identical

    sidenote DO NOT USE THE 1.8v at the front (close to usb connector) ... use the solder lug between fpga and trx chip named 1p8v_clk!!!

    the 1.8v at the front is a bit "dirty" while the 11.8v clock voltage is superclean

    there is a reason why AD mounted a special low noise voltage chip in front of the xo (now tcxo) and that power chip only powers the clock and nothing else ... wh9le the 1.8v at front powers different things (and so is a bit noisy)

    If you use a new tcxo inside he pluto the external ref command does not work ... cause new tcxo has no enable pin (to switch it off) .. i rerouted that switching transistor from enable pin of xo ... to enable pin of the power supply ic for the clock (u12) .. now i can have both .. a stable internal clock and still have the option to feed external 40 megs in

    (feel free to ask for details)

    the pluto has a frequency "nailed in stone" in uboot-extra-env.dfu.

    example:

    VíÞserial=1044734c9605000cf9ff120010c84f79ec productkey=d9f04f074f5e6992d04b879a176410570a3ed77a ad936x_ext_refclk=<39999843> ÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿ

    now the pluto "thinks" on boot he has a ref clock tha is157 hz low

    xo correction = 40 000 000 plus setting also 40 megs in sdrconsole and all is well

    in pluto options calibration set the checkbox to "apply corrction when connecting to pluto" and the 40 megs is sent to pluto on boot

    LET THE TX OFFSET AT 8089.5!! and set XIT to 0 !!!

    if done well you should be spot on (except the doppler shift of around 150hz)

    Hi,

    Maybe R5 near TCXO that missing is for disabling internal TCXO.

    disabling internal tcxo (now) is done via enable pin and q2 and not via r5!!

    r5 can be installed if you solder in a tuneable tcxo (and want to tune it via auxdac voltage!) ... if you replace tcxo with any other (as example astx13/asvtx13) with no enable pin then switching to external reference does not work anymore ...but i had a clever idea to solve that

    solution is to rewire Q2 to pin 4 of U12 (enable pin of 1p8v_clk regulator) ... so instead of switching enable pin of the tcxo ... you switch enable pin of the power regulator ic that powers the tcxo

    (time for a revision e ?!?)

    why the hell did they not install in minimum the 0.5ppm tcxo from factory?!? grmbl grmbl

    how is rewiring done?? lift pin 4 of u12 ... and rewire that enable pin to R67 (cut connection to enable pin of tcxo)

    r101 ... disconnect from 1p8v_clk and rewire to solder lug pg_1p3v

    now selecting external reference switches power of tcxo instead enable pin of tcxo

    that pin is now free ... so a tuneable tcxo can be mounted (with trimmer or with installing r5 and using ad9363_auxdac)

    happy modding DG9BFC (big fat chicken, beat frequency counter, bastler für charly?)

    it was me ... just to show HOW CLEAN AND NARROW such a signal from the keyer software is (the news reader has the same setable rise and fall time settings as the "normal keyer" ... a bit longer rise time ... and signal is VERY narrow)


    its a nice tool to spread out news (or other urgent messages) ...


    AND IT WAS JUST AN EXPERIMENT!!


    SORRY IF SOMEONE FEELS UPSET ABOUT THAT!!


    i wanted to show how narrow (no keyklicks!!) such a signal can sound over the air ... much better as switching on sdr console to tx (permanent on with tone !!!)) and key the amp on and off to send cw signs


    yes i have seen and heard such signals on qo100 ... UGGLYYY WIDE SPLATTER


    it was just to show a superb cw quality (remember it was just to SHOW IT IN LIVE)


    so at least we know it works fine (and i switched the news reader off for now)


    the keyer soft produces a superb cw signal quality ... and thats all i wanted to show with the newsreader ...


    greetz sigi DG9BFC


    best 73 and cu on the bird :-)

    IT IS THE NEW TRANSPONDER ... tune sdr console to 11.970 and see the stripes


    (if you have a different lnb frequency is a different story!)


    in some setups 2 gig is a few db lower and noise can not be seen (or just barely) depending on how your setup is done ... length of cables... bias t used etc etc

    many things influence the losses on 2 gig while on 740 megs all the attenuation factors are a lot lower ... and that is the reason why some do see those streipes and some do not ...


    the stripes are NOT from lte (even if an lte filter helps in this case)

    Nearly all sdr have a problem that they also receive the 3 times and 5 times (and above) frequency

    means if you have your rx tuned to 740 megs (rounded up a bit) ... it also receives on 2.22 gig


    since a few days a new tv transponder on the sat was switched on on 11.970 ...

    minus 9.75 equals 2.220 ... voila we have noise on 740 megs :-(


    several ways to solve it


    you can add a narrow 740 megs filter in your setup (there are saw filters available for that range)

    you can add an "lte-filter" in the lnb cable (a 800 megs lowpass filter with dc feed trough)

    you can add a 2.2 gig notch inside your bias t (just an inch of coax need as an open end stub)


    i now have two of the above solutions combined (the lte filter PLUS the notch for 2.2 gig in bias t)


    normally one of the three solutions should be enough but i got the lte filter after i added the notch so i left it in


    spectrum now is super clear again


    greetz dg9bfc sigi