[Elecraft] Boots for the XG3...off reflector...

[John Ragle]

Hi, Joe...

     You're quite right. I did the ff experiment: connect the XG3 to the 
K3 input, set the XG3 to 50.100 MHz, set the K3 to 50.250 MHz, turn on 
the XG3 and measure the increase in background noise on the P3.

     In my case, the noise floor for my K3 looking into a dummy load is 
-148 dB. Looking into the XG3 OFF it is the same, -148 dB. Looking at 
the XG3 ON and set at -33 dBm, the K3 set at 50.250 MHz, the noise level 
is -112 dB...that's 36 dB. It's a noisy sucker, alright...

     I had not appreciated just how noisy. Of course, these conditions 
are not very representative of on-the-air actualities, but you're quite 
correct.

     My motivation in all this has been the commentary we've been seeing 
on the reflector about running an XG3 wide open into a directional 
antenna with no filtering (quite illegally, IMO), and I hadn't 
considered the noise generation question at all. When I've used my XG3 
on my K3, it has always been set at -107 dBm, and no change in the noise 
floor is observed.

John Ragle -- W1ZI

=====

On 6/25/2011 1:55 PM, Joe Subich, W4TV wrote:
> I'm even concerned at 1W.  The XG3 is spec'd for -105 dBc/Hz.  I can
> see a noticeable increase in the noise floor of my K3 on 50 MHz when
> the XG3 is set to -33 dBm.