Posts by PA3FYM

    I reckon when the 3IMD products are somewhat more than 30 dB down it's fine because the dynamic range of the NB tpx is also around 30 dB (provided you're not using to much uplink power and stay below LEILA ; -)


    SV1BDS B.t.w. I received the CETC CTI OSC5A2B02 10 MHz OCXO today. Will take a little time to test it because I have too much projects to finish (like doubling the shelf surface with MDF in my shoe cabinet ; -)

    DD0KP Heiner, from the question of AMSAT (see initial posting in this thread) I thought it may be a nice idea to propose 'an emergency frequency'. To prevent a discussion on 'what' frequency it should be, I followed my statement with a proposal (.660) to align 'the noses'. I also stated it's fine with me when another frequency is favourable (as long as everyone knows that frequency).

    So, it doesn't have to be .660. To summarize: I take the blame! ; -)

    For every lens you need to adjust the focal point, because the phase centers are not the same.

    Not: keeping the LNB in place and exchange the horns/lenses.

    Hmm... that are almost equal pictures. Can you make two pictures where there is key down of the CW beacon in both cases?

    Try to set the sliders such that you've 40 dB 'dynamic range' in the pictures to prevent that the beacon clamps with the 80cm dish?

    Is it an idea to define 10489.660 as emergency frequency (also for future use) ?


    That is, when there is no emergency .660 is a 'normal' frequency. When there is

    an emergency .660 will be left alone by others (i.e. those not involved with

    the pending emergency / calamity).


    PS. Any frequency is fine with me, as long as everyone uses the same frequency ; -)

    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 ? ; -)