[amsat-bb] Leo Bodnar ICOM IC-9700 Reference Injection Board

[Kevin]

I wonder if anyone who has all the needed equipment to test has verified 
that the output of the 9700 is still clean after this mod?

    In the past ext reflock boards compared the radios osc to a gps 
locked 10mhz signal and adjusted the trim voltage going to the vctcxo so 
levels were not touched, the radio was as clean or dirty as it was when 
it left the factory.
   Now with this mod (if I understand it correctly) the main osc is 
still running and they are just pumping a much stronger signal into the 
master osc area until it drowns out the original osc and the radio locks 
to it.  So the question comes up are they then overdriving the osc chain 
downline and distorting? and is the original osc signal still there in 
the background now as noise?

Might be a interesting project to find out.

73 Kevin wa7fwf



On 2/15/2020 14:08, Bob Hammond via AMSAT-BB wrote:
> 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 <propgrinder at gmail.com> 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_id=301
>>
>> http://www.leobodnar.com/shop/index.php?main_page=product_info&products_id=352
>>
>> Bob W7OTJ
>>
>> On Sat, Feb 15, 2020 at 8:16 AM kd8drg.admin--- via AMSAT-BB <
>> amsat-bb at amsat.org> wrote:
>>
>>> I was wondering what the advantage is for using this board vs the
>>> standard 10Mhz external reference on the 9700?
>>>
>>> 73
>>> Eric
>>> WD8KNL
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> _______________________________________________
> Sent via AMSAT-BB at amsat.org. AMSAT-NA makes this open forum available
> to all interested persons worldwide without requiring membership. Opinions expressed
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