[eagle] Re: 10.7 MHz Spur

[John B. Stephensen]

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
>
>