This is a good explanation:
"With the current firmware, users have observed frequency drift when using narrow bandwidth modes. Using an external 10 MHz and the firmware reduces the size of the frequency drifts by updating the corrections to the master oscillator more frequently. The drift is still there,,,,, With the 49.152 MHz injector board and a good external 49.152 MHz GPS-locked oscillator, the external oscillator locks the internal oscillator and the drift issue is eliminated. The drift is probably not important on FM and most may not notice the issue on SSB. But it is important to eliminate the drift if you are using JT65 and similar narrow bandwidth modes."
Copied from the Facebook ic-9700 group and a post by Peter Freeman in reply to Tim Goodrich's question: https://www.facebook.com/groups/163460540873662/
Bob W7OTJ
On Sat, Feb 15, 2020 at 1:53 PM Bob Hammond [email protected] wrote:
Eric,
I found much information on the design and benefits of a GPSDO and reference board for the IC-9700 here:
https://www.minikits.com.au/gps9700#wspr
The Mini-Kits version is only slightly different than the Leo Bodnar version however the designs are virtually identical.
http://www.leobodnar.com/shop/index.php?main_page=product_info&products_...
http://www.leobodnar.com/shop/index.php?main_page=product_info&products_...
Bob W7OTJ
On Sat, Feb 15, 2020 at 8:16 AM kd8drg.admin--- via AMSAT-BB < [email protected]> wrote:
I was wondering what the advantage is for using this board vs the standard 10Mhz external reference on the 9700?
73 Eric WD8KNL _______________________________________________ Sent via [email protected]. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb