Posts by M0EYT

    Morning All,


    This isn't a rant but...


    One of the principles of AR licensing is the point of using it for technical self development, be it of skills, hardware, software, RF tech etc. We have been given access to a prize resource aboard a commercial comsat with the two transponders (nb/wb).


    IMHO we should be setting excellent examples of signal quality / purity, and of excellent operating practices. To see what I mean, have a look at some of the signals from Saturday last weekend;



    If you take the standard SSB as 3KHz bandwidth, or even Hi-Fi SSB at 4KHz you can easily see that there are some nasty signals, most likely caused by over-driving transverters, excessive use of compression, far too much mike gain etc. Some of the signals might be comparable to 'Zetagi 27MHz' equipment but we should be doing better than this by monitoring our own TX signals and ensuring they are clean and presentable before connecting our transmit equipment to an antenna; it is clear that ops have and do use the transponder as 'free test equipment'. Certainly in the UK one of the licensing stipulations is that you have equipment to receive on the frequency you transmit on, so it is very easy to monitor your own TX signal for quality / purity etc.


    I did stop using my FT897 noise generator after being horrified at the atrocious signal quality / PLL noise / broadband PA noise being emitted on transmit, it gave me sleepless nights so its been fixed through replacement.


    Is the behaviour possible to modify, probably not, but poor signals being excreted from badly set up ground stations might eventually cause issues for the satellite operator, who after all has a commercial platform to concentrate on.


    We can do better!


    regards,


    Paul M0EYT.

    Okey Dokey, there sounds like there is some interest for a QO-100 meeting, how about 1700 local in the room after Achim's talk ? I'll ask him nicely if he could mention it at the end of his talk in case others are not reading this forum, we could stay in the room, or migrate to the pub / bar (my preferred option).


    Look forward to chatting with lots of OM's!


    73's and good DX,


    Paul M0EYT.

    Twitter @UHF_Satcom

    Morning all,


    Wondering if there might be any interest in an informal meeting at Friedrichshafen of OM's that are active on the satellite? Maybe Saturday 22nd June would be usable? Always nice to put a callsign to a face !


    regards,


    Paul M0EYT.

    Morning Chaps,


    https://www.ebay.co.uk/itm/352183592481 is my current LNB. Its a dual output but uses two totally separate downconverter chains. I've left one as is for DATV transponder maintaining good Pn, and the other is reflocked to a 24MHz leobodnar GPSDO for the n/b transponder.




    Once the external ref was attached, I added Cu foil from the casting to the coax ground. The lid was replaced and sealed with Ally a/c duct tape for an RF tight seal, performance so far is excellent.


    Hope that helps someone.


    Paul M0EYT

    Twitter @UHF_Satcom