I was testing tonight into a dummy load and noticed some very peculiar behavior.
When connected to the dummy load on 14.179 MHz (USB) I see the noise floor (signal) in the panadapter as a flat line from -10K to +10K Hz at about -145 dBm. That looks good to me
Now I change frequency to 14.178 MHz and I see the signal rise to -130 dBm between -10K and -9.5K Hz. It is flat at -145dBm across the rest of the spectrum. Looks like more noise on the low end. Not so good.
If I change the frequency the to 14.177 MHz I see the signal rise to -113 dBm between -10K and -9.5K Hz. It is flat at -145dBm across the rest of the spectrum This shows a *lot* more noise.
Here come the strange part.
I change the frequency to 14.176 MHz and the signal looks just like the signal on 14.179. Flat across the entire spectrum at -145 dBm.
By changing the frequency down one kHz to 14.175, I see the signal that looks like 14.178 MHz. A small rise to -130 dBm at the low end again.
If I decrement the frequency down an additional kHz to 14.174, I see the signal that looks like 14.177 MHz. A large rise to -113 dBm at the low end again.
This pattern repeats itself through out the entire 20 meter band. The rise in the noise floor is a little less in magnitude at the very bottom of 20 meters (14.050), but by the time I get to 14.150 the rise in the noise floor is back to approximately -110 dBm.
I checked other bands and it exhibits this behavior on ALL bands. Always a three kHz stepping to repeat the pattern.
Anyone have a clue what might cause this behavior? I'm using the Delta 44 with the breakout box eliminator.
-Tim
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Tim Ellison
Integrated Technical Services
Apex, NC USA
919.674.0044 Ext. 25 / 919.674.0045 (FAX)
919.215.6375 - cell
Skype: kg4rzy
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