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<DIV>"There was a bad value in the Schmidt-trigger squaring circuit for the
10MHz reference input. R141, the emitter resistor of the differential pair, has
the wrong value. It should be 50Ω, not 100Ω. Change that an you won't have any
problems with using your external reference. "</DIV>
<DIV><FONT face=Calibri></FONT> </DIV>
<DIV><FONT face=Calibri>I see some odd type from time to time on this reflector.
In your post (cut and pasted above) you are talking about R 141. A resistor I
assume and it should be 50 ohm? Not 100 ohm? Is that right? I am not able to
replace an SMT component on a 5 layer board. I'll have to think about this.
What is the power rating of R141? I may have to find a SMT tech to do this for
me. I have two Anan-10 rigs. They both will need the modification. </FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=Calibri>Your reply is exactly what I was looking for Brian.
Thank You Very Much for your help. </FONT></DIV>
<DIV><FONT face=Calibri></FONT> </DIV>
<DIV><FONT face=Calibri>Best Regards,</FONT></DIV>
<DIV><FONT face=Calibri>Mike</FONT></DIV>
<DIV><FONT face=Calibri><A
href="http://www.w8bac.com">www.w8bac.com</A></FONT></DIV></DIV>
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<DIV style="font-color: black"><B>From:</B> <A
title="mailto:brian@lloyd.com
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href="mailto:brian@lloyd.com">Brian Lloyd</A> </DIV>
<DIV><B>Sent:</B> Thursday, March 14, 2013 4:57 PM</DIV>
<DIV><B>To:</B> <A
title="mailto:w8bac@comcast.net
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href="mailto:w8bac@comcast.net">Mike Monnier</A> </DIV>
<DIV><B>Cc:</B> <A
title="mailto:hpsdr@lists.openhpsdr.org
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href="mailto:hpsdr@lists.openhpsdr.org">hpsdr@lists.openhpsdr.org</A> </DIV>
<DIV><B>Subject:</B> Re: [hpsdr] Hermes/Anan 10 Drift?</DIV></DIV></DIV>
<DIV><BR></DIV>On Thu, Mar 14, 2013 at 1:52 PM, Brian Lloyd <SPAN dir=ltr><<A
title="mailto:brian@lloyd.com
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href="mailto:brian@lloyd.com" target=_blank>brian@lloyd.com</A>></SPAN>
wrote:<BR>
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<DIV class=im>On Thu, Mar 14, 2013 at 1:20 PM, Mike Monnier <SPAN
dir=ltr><<A
title="mailto:w8bac@comcast.net
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wrote:<BR></DIV>
<BLOCKQUOTE
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class=gmail_quote>
<DIV class=im>***** High Performance Software Defined Radio Discussion List
*****<BR><BR><BR><U></U></DIV>
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<DIV><FONT face=Calibri><FONT face="Times New Roman">My Apache Labs
Hermes/Anan-10 has, what looks like, frequency instability or<BR>drift that
seems to be caused by temperature
changes.<BR></FONT></FONT></DIV></DIV></BLOCKQUOTE>
<DIV><BR></DIV>
<DIV>Yes, you are right. I discovered the problem a month or so ago and worked
with Phil and the folks at Apache Labs (with whom I am quite impressed and
with whom I will happily continue doing business) about it. </DIV>
<DIV><BR></DIV>
<DIV>First, yes, you will see what appears to be temperature instability on
the internal 10MHz reference. If you look at the absolute numbers you will
find that this "instability" is well within the 1ppm specification. The
worst-case error I ever saw was just short of 2Hz at 10MHz, or 0.2ppm. Quite a
bit better than spec -- but still annoying. My first inclination was the that
there was a problem with the PLL that locks the 122.88 MHz clock to the 10MHz
reference. That was not the case. The problem turns out to be the way that the
10MHz internal reference is temperature compensated. Apparently it is
digitally compensated and therefore the corrections are quantized, hence the
sudden jumps. Yes, it is annoying, especially if you are a frequency
measurement geek like me. But that does not mean it doesn't meet spec or that
it can't be used, even for applications like WSPR.</DIV>
<DIV><BR></DIV>
<DIV>The other issue is the use of external reference
input. </DIV></DIV></BLOCKQUOTE>
<DIV><BR></DIV>
<DIV>(Sorry, I accidentally typo'd send.) </DIV>
<DIV><BR></DIV>
<DIV>There was a bad value in the Schmidt-trigger squaring circuit for the 10MHz
reference input. R141, the emitter resistor of the differential pair, has the
wrong value. It should be 50Ω, not 100Ω. Change that an you won't have any
problems with using your external reference. </DIV>
<DIV><BR></DIV>
<DIV>The ANAN-10 is a good FMT platform with a good 10MHz external reference. I
use either an LPRO-101 Rb reference or a Trimble Thunderbolt GPSDO with mine.
Works like a champ.</DIV>
<DIV><BR></DIV></DIV>-- <BR>Brian Lloyd, WB6RQN/J79BPL<BR>3191 Western
Dr.<BR>Cameron Park, CA 95682<BR><A href="mailto:brian@lloyd.com"
target=_blank>brian@lloyd.com</A><BR>+1.767.617.1365
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