[RFI] 2 MW Solar Farm

[Jim Brown]

On 9/22/2020 1:51 PM, Kim Elmore wrote:
> Will do. I have s cheap SDR that I can use to examine the local radio 
> environment. The question is what antenna should I use? I have a discone 
> up at nearly 60 ft and I'm tempted to look at 3-54 MHz using in. I may 
> try going down to 1.8 MHz but have a 1 kW AM BC station at 1.4 MHz about 
> 4 mi away and I dunno how well the SDR will handle that.

Hi Kim,

I strongly suggest that you study NK7Z's techniques for tracking RFI, 
and utilize them. The potential influence of that AM BC station is to 
define the overload point (or upper limit of the dynamic range) of the 
A/D in the SDR. If that's happening, it might pay to buy/borrow a BC 
Band HPF. But you might not need it if the sensitivity of antenna you 
use (like the discone) rolls off enough with frequency.

Also, depending on how that particular SDR aliases, you probably want to 
break the spectrum down into several segments and run Dave's plots on 
each of them, and for several different days of the weak for each segment.
> 
> I learned a little bit more: it'll be about 1 1/4 mi away and likely be 
> complete in 4-5 mos.

Since it's likely to be a physically large source, I would expect 
something on the order of -3dB per doubling of distance for direct 
radiation from the site itself. And at that distance, I would expect 
that you could null the direct radiation on the lower bands.

73, Jim K9YC