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ARRL FMT -- getting the most accurate frequency

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Comments

  • Bill W2PKYBill W2PKY Member ✭✭
    edited October 2019
    GetError has nothing to do with GPSDO. It’s the error caused by the truncated tuning word. Not every frequency can be directly represented by the tuning word.
  • W9WLX_ChuckW9WLX_Chuck Member ✭✭
    edited November 2019
    Everything you said it true, however the get_error command is only useful if the radio is GPS locked or locked to a 10MHz reference. The result does not take into account any drift in the internal OCXO or TCXO.
    http://wiki.flexradio.com/index.php?title=TCP/IP_slice#GET_ERROR
  • Ronald PanettaRonald Panetta Member ✭✭
    edited November 2019
    Bill, is there an area of the document that is misleading regarding get_error and GPSDO? If so, identify where and I will update the master to avoid any confusion.

    Ron
  • Ronald PanettaRonald Panetta Member ✭✭
    edited November 2019
    Chuck, I'll have to defer to the folk at Flex as all I did was pull together the "How To" and don't have enough insight into the internal workings of the Flex. 

    As to your results, the last 2 frequencies look to be the WWV frequencies less 1500Hz. Were you measuring WWV and providing the slice frequency?

    As to the other 2, I don't recognize those. DId you used a signal generator referenced to a GPSDO to generate the 2 test frequencies then measured the error on the 6600 using the method outlined by Steve and documented in my PDF? If so, one possible factor could be that GPSDOs are extremely accurate when averaged over the long term but not as accurate for short term measurements. 

    Ron
  • W9WLX_ChuckW9WLX_Chuck Member ✭✭
    edited November 2019
    Ron, yes I was measuring WWV.  The other two frequencies are two regional AM broadcasters in my area (620 & 1130 KHz).  I was curious what I would get measuring their frequency.  I used 100 measurements sampled over about 5 minutes and took a mean average for each signal.

    Thanks for putting the document together.  Nicely done!

    Chuck
  • Bill W2PKYBill W2PKY Member ✭✭
    edited November 2019
    Practicing for tomorrow night received a Slice Get_error -45.774696 on my 6700 running 3.1.8

    Ron, no problems with your document.
  • Dave KD5FXDave KD5FX Member ✭✭
    edited November 2019
    It's tonight at 8 PM CST, 7 PM EST.
  • Bill W2PKYBill W2PKY Member ✭✭
    edited November 2019
    Always forget UTC starts the days B4 here thanks Dave

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