24.9°E Alphasat (incl.)

  • This is the carrier from the propagation experiment on a nominal frequency of 39.402GHz, actually about 23kHz high.


    Received using an old experimental link RX head end, thanks uhf-satcom. An external, 9.5GHz, GPSDO locked source is multiplied to give a 38GHz LO. The noise figure is in the region of 8-10dB with a linear polarised feed on a 220mm Cassegrain dish. I did not get a chance to measure the polarisation angle as the down-converter developed problems. The beacon TX antenna is set to 45 degrees, linear polarisation.


    This has been used in conjunction with the Ka band beacon on 19.701MHz Vertical

    Images

    1.2m Prodelin 1224 az-el with one of:
    S: Helical feed, 0.8dB NF LNA, X: 1.2dB NF LNA, conical feed,
    Ku 12-18GHz: corrugated conical feed, 1.5dB NF LNA, Ku (Standard): Octagon OSLO mod for C120 & ext ref Prodelin feed.

    Ka: Gilat ex-ODU PLLs Gilat feeds, Ka 18-26.5GHz: Patriot feed, home made 4dB NF LNA, Ka DSN: Corrugated conical feed, home made 3dB NF Down-Converter

    1.5m IRTE, Polar mount with Octagon OSLO mod. C120, IRTE feed
    40km East of London, UK

    Edited once, last by s-band: Link added to Ka band beacon ().

  • I replaced the LNA with an HMC1040 and now get about 12dB better SNR. Changing the LO frequency to 38800MHz may have helped as well. Not that there's anything more to see! The beacon that used to be on 39402.7MHz is no longer on.


    1.2m Prodelin 1224 az-el with one of:
    S: Helical feed, 0.8dB NF LNA, X: 1.2dB NF LNA, conical feed,
    Ku 12-18GHz: corrugated conical feed, 1.5dB NF LNA, Ku (Standard): Octagon OSLO mod for C120 & ext ref Prodelin feed.

    Ka: Gilat ex-ODU PLLs Gilat feeds, Ka 18-26.5GHz: Patriot feed, home made 4dB NF LNA, Ka DSN: Corrugated conical feed, home made 3dB NF Down-Converter

    1.5m IRTE, Polar mount with Octagon OSLO mod. C120, IRTE feed
    40km East of London, UK

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