Effect of small hardware changes on 1m class hydrogen line radio dishes on removing radio frequency interference (RFI).

The following information is from Alex Pettit 23/12/2025:

For Example, in this case where local RFI is seen from an adjacent monitor to the receiver.

The following 3 plots show:

I had just completed a  24 hr drift scan and thought I’d do a few quick tests before tearing down.

Left = no RFI      Center High RFI with normal config       Right RFI Reduced with foll extensions.

1. If I turn on my monitor and it goes into sleep mode, I go from Centre spectrum (monitor on) to left spectrum (monitor off).

2. If I add the Aluminium foil extension on the reflector, the spectrum changes to the Right spectrum (with aluminium foil extension instead of turning off monitor).

Not Perfect, but it gives you an idea of things to try.

The plots show lower RFI by extending the V reflector .. may/may_not work depending on the source ..

Shown as an Example of the effect very small changes in Hardware  can make versus always chasing solutions in  Software  

I have no plan to refine this as I just turn the monitor OFF most of the time.

Yes, there may be secondary detrimental effects .. but sometimes trade-offs are required. In this case, noise floor seems to have increased slightly, although possibly this is due to some other factor that came into play as time progressed between centre and right plot.