[eagle] Re: 10.7 MHz Spur

Juan Rivera juan-rivera at sbcglobal.net
Sun Jul 1 20:19:03 PDT 2007


John,

 

The short answer is 'no'.  Click here
<http://www.juanr.com/pages/hobbies/ham_radio/Eagle/IMD+Phase_Noise.htm>
for details and scroll to the bottom of the log...

 

Juan

 

-----Original Message-----
From: John B. Stephensen [mailto:kd6ozh at comcast.net] 
Sent: Sunday, July 01, 2007 2:42 PM
To: juan-rivera at sbcglobal.net
Cc: eagle at amsat.org; Bill Ress; Dave Black (Home); Dave Black (Work); Dave
hartzell; David Smith; Don Ferguson; Juan. Rivera (Home); Juan.Rivera
(Work); Samsonoff at Mac. Com
Subject: Re: 10.7 MHz Spur

 

Does the spur go away if the external reference is on (whether or not it is 

routed to the PLLs)?

 

73,

 

John

KD6OZH

 

----- Original Message ----- 

From: "Juan Rivera" <juan-rivera at sbcglobal.net>

To: "John B. Stephensen" <kd6ozh at comcast.net>

Cc: <eagle at amsat.org>; "Bill Ress" <bill at hsmicrowave.com>; "Dave Black 

(Home)" <dblack1054 at yahoo.com>; "Dave Black (Work)" 

<dblack at mail.arc.nasa.gov>; "Dave hartzell" <hartzell at gmail.com>; "David 

Smith" <w6te at msn.com>; "Don Ferguson" <kd6ire at sbcglobal.net>; "Juan. Rivera 

(Home)" <juan-rivera at sbcglobal.net>; "Juan.Rivera (Work)" 

<Juan.Rivera at gd-ais.com>; "Samsonoff at Mac. Com" <samsonoff at mac.com>

Sent: Saturday, June 30, 2007 14:22 UTC

Subject: 10.7 MHz Spur

 

 

> John,

> 

> I found the source of the 10.7 MHz spur.  It's being generated inside the

> receiver itself.  This is the first spur I have found that is not caused 

> by

> switching power supplies.

> 

> The origin appears to be in the 10 MHz reference area.  I turned off and

> unplugged the SDR-IQ and fed the IF output from the 70 cm Receiver to my

> TS-2000.  The spur is still there.

> 

> Next I connected the RF input to my sniffer loop and moved it around the 

> PCB

> surface.  I get the strongest signal near the long trace between the two

> Freq inputs to U4 and U9, the two phased-locked loops.

> 

> 73,

> 

> Juan

> 

> 

 

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