Sunday, March 1, 2015

Band Noise

On eham I was in a discussion asking why the band noise seemed to slope up in my radio.  Here is a shot with no antenna connected to the 6300 on my RF patch panel.

This pic shows my spectrum from 1 mhz to 8 mhz.  Nice and flat with a couple spurs in the BC band.

Here is a pic with the freq flag at 1.8 mhz and my 80M vertical inserted into the 6300's antenna jack on the patch panel.

This pic shows the BCB band to a little over 7 mhz.  Notice how quiet 160M is.  The peak around 3.7 mhz is the resonance of my 80M full sized 1/4 wave antenna.  I can switch the picture by switching to my 40M 1/2 wave vertical fed through a resonant parallel network 

Here is up to about 10mhz on the 80M 1/4 wave.

I used this method to discover what the strongest signal presented to my ADC was and it turns out to be whatever station is on 7305 (this is on the 40M antenna)

He is peaking -37 dBm or so which is 46 dBm below where my radio crunches aka +9 dBm.  On the 80M antenna the culprit is Radio Havana at 6mhz but they are still 39 dBm below crunch time.

73  W9OY