Best HQDL 414 Plus Quattro LNB for QO-100?

  • I ordered from Amazon the OPTICUM LSP-04H. LNB


    but for some reason this morning I received a DAXIS AS0420 LNB


    I just tested the Daxis and it drifts about 8KHz! I left it running for a few hours.


    There is no mention on the spec if its a DRO or PLL type, anyway its as bad as the old DRO LNBs which I already have.


    I will contact the Amazon seller to see why he sent a different LNB model


    If I manage to get hold of a OPTICUM how much drift should I expect?


    Thanks



    Technical characteristics: DAXIS AS0420 LNB

    • Input Frequency:
    • Low band: 10.70~11.70 GHz
    • High band: 11.70~12.75 GHz
    • Output Frequency:
    • Low band: 950 ~ 1950 MHz
    • High band: 1100 ~ 2150 MHz
    • Local Oscillator:
    • Low band: 9.75 GHz
    • High band: 10.60 GHz
    • Noise Figure: 0.1 dB (típ.)
    • Gain at 25ºC: 58 dB (min.) / 63 dB (máx.)
    • Gain stability: ± 0.5 dB / 26 MHz
    • Crossed Polarization Isolation: 25 dB (típ.)
    • Local Oscillator stability:
    • ±1.0 MHz (max.) @ +25º C
    • ± 2.0 MHz (max.) @ -40º C ~ +60º C
    • Phase noise of the local oscillator:
    • -50 dBc / Hz @ 1 kHz
    • -75 dBc / Hz @ 10 kHz
    • -95 dBc / Hz @ 100 kHz
    • Image Rejection: 40 dB (min.)
    • VSWR: 2 : 1 (tip.)
    • Current consumption: 70 mA (máx.)
    • Band Change:
    • Low Band: 0 kHz
    • High Band: 22 kHz ± 4 kHz
    • Voltage - polarization change:
    • 12.0 ~ 14.0 V Vertical
    • 16.0 ~ 20.0 V Horizontal
    • Operating Temperature: -40ºC ~ +60ºC
  • I ordered also from Amazon and became an other Opticum model, but the LSP-04H was OK. I think you received a "compatible" model with PLL. DRO type models are not on the market, except on flea markets, its an old technology.


    8kHz drift is normal after switch on. Does your DAXIS wobble ? That's much more important than drifting. Wobbling without a modification makes the LNB unusable.

  • I ordered also from Amazon and became an other Opticum model, but the LSP-04H was OK. I think you received a "compatible" model with PLL. DRO type models are not on the market, except on flea markets, its an old technology.


    8kHz drift is normal after switch on. Does your DAXIS wobble ? That's much more important than drifting. Wobbling without a modification makes the LNB unusable.

    The Daxis LNB has no wobble at all and after being plugged in for 8 hours there is only a drift of about 800 Hz so much less than after 2 hours.

    maybe because the sun is not shining on the LNB in the evening so a cooler temperature is not so drifty?

    Anyway if the Opticum is no better I may as well keep this Daxis.


    Image shows drift over 4 mins on a slow waterfall.

  • The Daxis LNB has no wobble at all and after being plugged in for 8 hours there is only a drift of about 800 Hz so much less than after 2 hours.

    maybe because the sun is not shining on the LNB in the evening so a cooler temperature is not so drifty?

    Anyway if the Opticum is no better I may as well keep this Daxis.


    Image shows drift over 4 mins on a slow waterfall.

    It's not so much about the absolute temperature, but about the change in temperature. If there is hot sun shining in an LNB with a black case, and there are some gusts of wind, for example, it can drift quite a bit back and forth, as the sun heats it slightly, and then comes the wind and cools it down a little. If the temperature is stable, its absolute value does not matter that much. I also observed my unmodded LNBs tend to be more stable at night here at my location, but YMMV.

  • Hi,

    no matter what lnb you use, they ALL will drift, even when modified with a better oscillator. Maybe some really expensive ones won't drift. If you want only small drift, do not replace the built in oscillator by a better built in oscillator. Instead, feed the reference via coax from a place with minimum temperature changes, preferably from your shack. 25MHz multiplied by 390 is tricky to stabilize. A slamming door can cause frequency changes. I had a gps controled 25MHz vctcxo in a box and even this drifted a small amount for a moment caused by the moving air when i opened the shack door , then quickly settled again. A ocxo may do the trick. The one i used was cheap , not very accurate, but rock stable, meaning i had an offset of about 1.5kHz on 10GHz, but virtually no drift. Currently i use a gps controled vcocxo , everything is fine. So you see, there are different levels of accuracy and stability. You should start with a normal lnb and let sdr console take care of the drift. Once you are using the satellite you will quickly learn what level of stability/accuracy will suit your needs.

    73, Martin


    Edit: If you go for a (vc)tcxo, please be aware: Some of them change their frequency in steps. Some kind of "digital" hops. You don't want that. Others change their frequency smoothly. That is what you want.

  • Hi,

    Even OCXO is temperature affected!!! When I build Lars GPSDO and use modified code by PA3FYM when I open or close the air condition it was loosing lock and the code was modified in order to handle such changes. This GPSDO was compared to Cesium and a drift of +-2 Hz at 10 GHz was noticed. It is not perfect but such a stability is more than enough for QO100.