external gpsdo - indication that it is connected & working?

Tom Porada

I just installed the Jackson Labs LC-XO-Plus. It has lock (took about 30 minutes as expected). I plugged it into the Flex 6500 when it was turned off. I understand that the Flex checks for an external signal during boot.

Is there any indication of interaction between the Flex and the GPSDO? Nothing is obvious.

Anything else need to be done other than plugging it in after lock and before boot?

Duane_AC5AA

I don't have one, but have you checked the GPS screen on the radio settings window in SSDR?

Tom Porada

According to the user guide, that setup is used only for the internal Flex GPSDO. The way I understand it, a piece of software is installed to check/enable the internal module when the 'install' button is pushed in that setup area.

Walt

I think an "Ext. Clk" indicator is on one of those "List' things that Flex keeps someplace.  As to where on the list, and when they will get to it is . . . . . . . . . . . . or if they even feel like doing it at all . . . . . . . . . .  

I think it was suggested two years ago, if that gives you any idea as to its priority level.

Cheers and have a few pints . .

Tom Porada

I just found a four month old post from Tim:
"it is on the to do list.  In the mean time, if the radio stops clicking every few seconds after you boot the radio, then the master oscillator is locked to your input clock source."

Guess I'll check it on my next on/off cycle.

Al K0VM

If you start running on an external 10Mhz reference, you should also redo your OffSet Calibration.  With an external GPSDO the auto correction should be near zero. 

AL, K0VM

Tom Porada

Al, on the setup 'Receive' tab I show a Cal Freq of 15 MHz and an Offset of -1.

Are you suggesting that I change the -1 to 0  or press the 'Start' button  or ??

Thanks.

pa0bie

Be sure that the ext.ref input signal has the right level. With a to low level I had some very strange behaviour as a frequencie offset between Tx and RX. With any GPSDO , intern or extern , the Offset Calbration in the radio setup should be zero. A indication that the ext.ref is available and within the right level  is one off the issue's I am waiting for more then 2 Years.

Al K0VM

What I was  suggesting is to use the AutoCal test as a means of verifying the the GPSDO was working..... If its not, then the correction would almost sure to be much larger...     Whether you set -1 to 0 will not likely be noticable except maybe in a FMT..  and I am not sure which would be more accurate.

AL, K0VM

Tom Porada

Al - I assume that you are referring to the start-up auto calibration test done at boot up without operator intervention. Nothing I can control there. All I can do is to make sure I don't hear too many clicks (see previous post with quote from Tim) to determine if the GPSDO is working (I seem to hear fewer clicks than before).

In the V1.6.21 Hardware Reference Manual, page 45, sec 15.1 Frequency Calibration,  it discusses calibration of a Flex without the installed GPSDO which can be calibrated by the user utilizing the automated routine provided in the SmartSDR client software. I have not been able to explicitly find a calibration procedure in the SmartSDR v1.6.21 User Guide. I hesitantly assume this refers to the Radio Setup in the Receive tab as we've been discussing above. With that said, would the intention be to change the Cal. Frequency from 15 MHz to 10 Mhz (as provided by the external GPSDO), ignore the offset (assuming it would be auto determined) and press the Start button to start the calibration procedure?

As with most things in life, until you dig deeper you simply don't know what to expect. Wrongly so, I assumed that Flex would have documented the details of using an external reference with more detail, perhaps a separate document.

And yes, I was seriously thinking about the FMT in a few days but doubt I'll be up to speed on understanding with confidence how to use FLDIGI for that purpose.

Thanks again.

Al K0VM

Tom,
    Althought the auto cal routine is intended for calibratiing the internal Reference, It can also be used to verify that the External ref is proper connected and functioning.   Set the CAL Reference for the freqeuncy that you best receive WWV on.  A auto cal run with the inteternal reference will likely produce a non-zero offset result.  WIth the GPSDO operating the test should produce a near zero result.

AL, K0VM

Tom Porada

Al

You should write a white paper on how to use an external 10MHz source!!

With the GPSDO unplugged the boot auto cal returns a -1 (set at 15MHz).

With the GPSDO plugged in the boot auto cal returns a 0 (set at 15MHz).

I could not tell much from the number of clicks as suggested previously by Tim.

Although I only ran one test, it appears as though my GPSDO is operating as expected.

Thank you...now write that paper!!

Tim - W4TME

Is there any indication of interaction between the Flex and the GPSDO? 

No, there is not other than the radio does not click every 1-2 seconds after it has booted to indicate it has found a suitable clock source.

And running the calibration routine should be an indicator too.  Returning a stable offset value close to 0 will indicate that the source is accurate to 10 MHz and stable.

W5XZ - dan

Tom, can I ask where you bought it?  couple quick google searches don't turn up sources, for me anywah.

73, w5xz, dan

Tom Porada

Dan - W5XZ:  The only place to purchase the XC-LO-Plus is directly from Jackson-Labs in Las Vegas - look them up on the web. The GPSDO is very small - about 1"H x 2"W X 3.5"D.. It is to the right of the Flex in the pix below. Contact me direct if you need more info.
Going to try to complete my study for the ARRL FMT this evening using the 6500 with the GPSDO.

Phil M0VSE

I use a BG7TBL GPSDO and it seems to work well. One way to tell that the flex is 'locked' is to unplug the GPSDO and if it is working, you will hear a relay click in the 6500/6700 (presumably switching to internal TCXO).

Interestingly, when I run the calibration option, it is always +3 when using the GPSDO (compared to around -600 without it)

73 Phil

Tim - W4TME

Interestingly, when I run the calibration option, it is always +3 when using the GPSDO (compared to around -600 without it)

Not that interesting.  I would expect the internal OX to need greater offset correction than a disciplined clock source.