Posts by PA3FYM

    I mean the difference between your system noise and the received noise from the tpx.

    E.g. pointing towards QO-100 you receive on 10488.000 MHz noise, and you receive noise on 10489.525 MHz.
    How large is the difference ?

    DH1DA This ADF4351 is actually a complex and versatile device. For generating signals there are several routes to Rome.


    From what I learned from the 'black science' of PLL's and (especially!) loop filters, is that a 'normal' INT PLL with lowest N as possible (and therefore highest PFD possible) delivers the cleanest signal. As a rule of thumb phase noise increases with N^2 (N-squared, or 20logN).


    The FRAC mode isn't bad, but depending on the loop filter on these board. So .. for this given loop filter it needs a little experimenting with different settings (PFD and BW) to find the most optimal settings or you have to replace the loop filter components on the ADF PCB, which is a tedious job.


    I built several applications with these PLL's (also passive, i.e. external oscillator and 'seperate' ADF PLL (like ADF4001, 4118, 4113, 4153 etc) and found that for every case I needed to fiddle and burnt hours struggling with ADISimPLL ;; -)

    From the datasheet it even has better P/N performance than the Bliley, but it's square wave and that often may be a nuisance because of harmonics 'flirting' around ; -)

    David G0MRF try PFD of 2.5 MHz (or 500 kHz) as PFD and use INT-N.

    You now do not have INT-N (N = 393.5)


    2.5 MHz is GCD of 1967.5 and 10 MHz.


    1967.5 / 2.5 = 787 (which is an integer ; -)


    (you can also see it's not an INT because FRAC = not zero)


    Use R-counter = 4 for PFD 2.5 MHz, or R-counter = 20 for 500 kHz PFD

    (set 'channel spacing' accordingly, or omit the errors ; -)


    (and I am personally a fan of 4/5 prescaler)

    DB2OS : No no .. no scaring at all, but nice pleasant talks with a few technical people (they are not all sales). I am aware that the commercial satellite world is very well regulated in itself, for obvious reasons. I also had some conversations for business purposes concerning Ka tpx's. I advised one of them to obtain his amateur license after which he shook hands : -)


    I am also aware that the ∫ integral over the passband shall not exceed the nominal TWT power (OBPO included).

    Perhaps in Es'hail-3 a separate TWT (and back up ; -) for the amateur service ? ; -)

    I think nobody expected these problems.

    I did.


    Having significant 'hands on' experience with SNG (satellite news gathering) in one of my former lives, and as former satellite co-ordinator of the Dutch government I spoke with several co-workers of Es'hailSat during IBC2018 and IBC2019 concerning 'how to deal with an 'undefined' user group'. They were flabbergasted ...


    I fully agree with the posting of Achim DH2VA . The QO-100 tpx is a gift, something the satellite owner (Es'hailSat) offered us (i.e. the amateur community). In other words, Es'hail-2 is not founded 'for us'. We mooch. The satellite is intended to offer extra capacity for forthcoming global activities (...football) so, it's primary goal is NOT to serve the amateur community.


    Bear that in mind and be humble (<-- also addressing pirates!)

    Yes, that is the ICSP port where you can program it. But .... if indeed the ATTiny45 is put into 'USB' mode, it may be that also PB5 is used, that means that it can't be programmed 'normally', but you need to HV program it. (Google on it)

    Looks like the USB interface is made from an ATTiny45 , same as USBTiny programmer for e.g. other ATTiny's.

    So perhaps George you can look into that direction?

    Having laughed at IRC, I (re)viewed your movie twice, but I am not convinced. It's not the Bodnar (assuming you use(d) that) but I suspect the instability of the IC-402.


    I think you need more samples with all LO's GPS locked and also accelerate en slow down etc ; -)


    Anyway, creative and nice experiment! : -)

    DB2OS I like your post, but I don't like its contents : -(


    It was not a matter 'if' , but 'when' this should/could occur. Unfortunately you can't force 'the customer' (like for 'normal' transponder rentals) to reduce uplink power, but hopefully you and your team have sufficient measures to prevent TPX mute.


    Edit: This weekend is the ARRL EME contest 2.3 GHz and up ....