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Frequency Offset, "offset (in ppb)

Ian1
Ian1 Member ✭✭
edited June 2020 in SmartSDR for Windows
In the Radio Setup using 15Mhz I am now getting a reading of -684 ppb is this level acceptable?

Ian
«1

Answers

  • Bob Brown - N8OB
    edited February 2018
    Mine runs at +480 and is correct.  The reading you are getting sounds like you are not seeing 15Mhz correctly.  Have you tried it on 10 Mhz?

  • Greg N8GD
    Greg N8GD Member ✭✭
    edited June 2018
    I don't know if the radio compensates for it or not, but I always try to do the calibration during the portion of the WWV signal when there's no tone modulation.  Listen to the signal before you run the calibration routine and find out when the tone is not there - the last 15 seconds of most minutes, if I recall correctly.  I also seem to have had better luck with 10 MHz even if the propagation favored the higher frequencies on a particular day or at a better time of day.

    Last time I calibrated mine (a few months ago, after they fixed the problem with the calibration not working in SSDR), my 6300 has an offset of -127 at 15 MHz (looks like I don't follow my own frequency advice!).

    Greg - N8GD
  • Bob Brown - N8OB
    edited February 2018
    If you use the calibration procedure on the radio, it takes the radio into 15Mhz or whatever freq you are using on WWV.  It will automatically adjust things correctly.
  • George KF2T
    George KF2T Member ✭✭✭
    edited February 2019
    Yes, your value is well within acceptable limits. It will vary from measurement to measurement.
  • David Decoons, wo2x
    David Decoons, wo2x Member, Super Elmer Moderator
    edited June 2020
    my 6700 is consistently around -2300
  • Lawrence Kellar KB5ZZB
    Lawrence Kellar KB5ZZB Member ✭✭
    edited February 2017
    My 6700 is at -4000 ppb.  I have a help desk ticket opened for about a week waiting for an answer.  It is very stable though.  
  • George KF2T
    George KF2T Member ✭✭✭
    edited February 2019
    This value is the correction applied to an internal component to bring the system to "exactly right." Whether or not it is a part per billion or 4 parts per million is not really important, as long as the value is relatively stable over time. A "large" value, as reported by Lawrence, for example, doesn't indicate a problem. It represents 8 Hertz correction (not error) at 30 MHz. If having a harmless value present makes you nervous, the GPSDO option may be for you.
  • Lawrence Kellar KB5ZZB
    Lawrence Kellar KB5ZZB Member ✭✭
    edited June 2020
    Thanks. All I needed to know was that it was ok. I just wanted to make sure it wasn't a symptom of a more serious problem I did learn however that you have to have your antenna connected to antenna one to calibrate. You cannot calibrate off of antenna two
  • Ian1
    Ian1 Member ✭✭
    edited May 2020
    Gentleman

    Thanks for all the info the past few months I have measured the WWV signal and have got a consistent -664 to -684 value.

    Appreciate all the info as this feature other then how to use it doesn't mention a value that is acceptable.

    Ian
  • Tim - W4TME
    Tim - W4TME Administrator, FlexRadio Employee admin
    edited December 2016
    If the calculated value is out of range, an error occurs.  if you get a non- zero value, it is safe to assume that the test was successful.
  • Tim - W4TME
    Tim - W4TME Administrator, FlexRadio Employee admin
    edited December 2016
    We calibrate on the carrier, not the tone pulses.
  • Tim - W4TME
    Tim - W4TME Administrator, FlexRadio Employee admin
    edited March 2017
    The short answer is yes.  
  • Rick  WN2C
    Rick WN2C Member ✭✭
    edited May 2018
    Would you get different results using different offset frequencies for WWV?
    I get slightly different results using different freqs from WWV. They all range from 128 to 118.
    Just so I understand how this calibration works, it takes the offset and applies it to a device in the radio to correct it? And once applied it is exactly on frequency?
  • Tim - W4TME
    Tim - W4TME Administrator, FlexRadio Employee admin
    edited December 2016
    Differences in atmospheric Doppler frequency shifting could account for it.

    Once the calibration routine has run, the radio is on frequency within spec based on the frequency source using the offset calculated. 
  • Lawrence Kellar KB5ZZB
    Lawrence Kellar KB5ZZB Member ✭✭
    edited December 2016
    I just got word back from Flex. 4000 is out of spec and I will have to send my radio in. It looks like it is time for a nice leisurely drive to Austin. The last time I shipped the radio it cost me $120
  • Ian1
    Ian1 Member ✭✭
    edited July 2016
    Thanks Tim
  • David Decoons, wo2x
    David Decoons, wo2x Member, Super Elmer Moderator
    edited July 2016
    Did they say what is considered maximum? Mine is around 2300 consistently. Dave wo2x
  • Lawrence Kellar KB5ZZB
    Lawrence Kellar KB5ZZB Member ✭✭
    edited December 2016
    No they did not.
  • Gerald-K5SDR
    Gerald-K5SDR FlexRadio Employee ✭✭
    edited April 2019
    The answer is that if the frequency calibration function works and the frequency is stable your radio is operating properly.  It should always generate a non zero value it the routine has properly calibrated.  The stronger the calibration signal, the better the accuracy.  The higher the frequency of the calibration signal the higher the accuracy.  The absolute offset is not critical so long as calibration works properly.  Expect the values to change over time deviating further from zero due to normal aging.  

    Gerald


  • David Decoons, wo2x
    David Decoons, wo2x Member, Super Elmer Moderator
    edited June 2020
    Thanks Gerald. Just making sure the 6700 is ok. I know after software upgrade you need to recalibrate. Dave wo2x
  • Ken - NM9P
    Ken - NM9P Member ✭✭✭
    edited December 2016
    As many updates as I have run in almost three years as a 6500 owner and several months on the Alpha Team, I STILL often forget to run CALLIBRATE when I am finished installing the update.  I need to add that to my update check-list.

    My rig is stable enough that I just don't go there very often.  My rig currently calibrates at about -685 from its standard....not bad after three years! 
  • Tim - W4TME
    Tim - W4TME Administrator, FlexRadio Employee admin
    edited December 2016
    You do not need to re-run a frequency calibration of the 6000 after a software upgrade.  The frequency calibration is stored in the non-volital EEPROM.  A factory reset would not overwrite the XO offset data 
  • Ken - NM9P
    Ken - NM9P Member ✭✭✭
    edited December 2016
    OK, thanks, Tim.  That is good to know. 
    (That was probably one of many things that changed along the line of the many updates over the past three years?)

    I apparently have some other issue that is occasionally zeroing it out.  Perhaps changing between different clients, i.e. between SSDR, DL8MRE Radio App, (Alpha)  & K6TU's Remote.  I just assumed that it was zeroed out after an update or two. 

    I might have done a persistence reboot somewhere along the line, also.  I seldom need to do that but I may have done it after a glitch and forgotten about it.

    Ken - NM9P
  • Tim - W4TME
    Tim - W4TME Administrator, FlexRadio Employee admin
    edited December 2016
    The only thing I am aware of in the code that would zero out the frequency cal offset data is if the radio thinks there is a GPSDO installed.
  • Ken - NM9P
    Ken - NM9P Member ✭✭✭
    edited December 2016
    Hmmm. 

    Does the CAL setting get saved in a Global Profile?
    Could I have saved one with Calibration of zero, which would reset it to zero when I reload the global profile?

    I am not near the rig to test it now, but now I am intrigued to solve this mystery.....(not a problem or an issue...just an unsolved mystery.)

    It might have been zeroed out when attempting to calibrate from DL8MRE over a marginal connection that didn't finish the job, or perhaps a glitch in the Radio App, or a bad data file in it's settings......(at this point I don't even remember if the DL8MRE alpha has implemented the calibration routine.)

    No biggie.  Just my problem-solver personality kicking in......ha..... "Something is afoot, my dear Watson!"


  • Tim - W4TME
    Tim - W4TME Administrator, FlexRadio Employee admin
    edited December 2016
    No.  It is stored in the EEPROM with all of the other radio calibration data.
  • David Decoons, wo2x
    David Decoons, wo2x Member, Super Elmer Moderator
    edited July 2016
    I too have see the cal setting get zeroed out. It very well could be from bouncing back and forth between different clients (SSDR, Maestro, DL8MRE< K6TU, etc).

    I hardly ever turn off the radio but when I did the other day I noticed the yellow light was staying on but I do not have the GPS option installed. I uninstalled the GPS from the radio setup and the light now goes off when powered down. This thinking the GPS is installed could have been the cause of the calibration getting reset to zero.

    I will do some testing later today switching between clients to see if something is setting the radio into thinking the GPS is installed.

    Dave wo2x

  • PA2TA
    PA2TA Member ✭✭
    edited June 2019
    Just wondering, over here in Europe i get (very) different results for every attempt to calibrate my 6300. Which makes sense because WWV is far out of reach, i presume the radio does not switch to another standard signal for Europe?

    SSDR v1.8.4.168
    HW version v1.8.4.84

    Tjakko PA2TA


  • Tim - W4TME
    Tim - W4TME Administrator, FlexRadio Employee admin
    edited December 2016
    Tjakko,

    I am aware of other time sources world-wide
    http://www.dxinfocentre.com/time.htm

    Just manually enter the frequency of one of them which is providing a strong signal into the calibration routine and use it.  Remember to press the Enter key after entering the new frequency.
  • PA2TA
    PA2TA Member ✭✭
    edited November 2016
    Hi Tim,
    Thanks for the response, at the moment the only usable station is RWM in Moscow on 4.996, it is abt S7 or -97dBm, the noise floor is at abt -100dBm. I still get very different results, varying from -12 up to +786, maybe the signal is not strong enough?

    I will try some other freq's later, for now its time to call it a day.

    Tjakko PA2TA

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