[Elecraft] [K3] Using K3 for relative noise survey

[Dave Cole]

On 08/01/2017 06:33 AM, Rick Miller - N1RM wrote:
> I currently live in a townhouse and have made an offer on a few acres in a
> more rural area. I would like to measure the relative noise levels between
> the two locations to reduce the probability of surprises or disappointments
> should I close the deal.  I have gotten access to a very good battery
> powered spectrum analyzer and plan to use a tripod-mounted 6 foot whip and a
> 20 dB LNA to measure the noise levels at each location.
> 
> While setting this up, I though it would be interesting to try to also use
> the K3 to measure noise with the same antenna (but without the LNA).  I've
> written a Python script to control the K3 as it steps through each band and
> records S meter levels.

Might I suggest this:

http://nk7z.net/sdr-rfi-survey-p1/

blog entry.  It is a way of using a cheap SDR to get an overview of your 
RFI environment, and a way of being able to compare two environments.

We are going to move soon, and I wanted a way to do exactly what you 
described here.  I wanted a way to characterize the RFI on an entire ham 
band at once, and this fills the bill well.

> My first run through very late last night showed almost no variation across
> any of the bands.  I did see differences between bands.  Right now I pause
> for 1 second after setting band, mode, and bandwidth, and then another
> second after each frequency change (stepping in 10 KHz increments) for
> things to settle.
>   I don't know the dynamics of the S-meter processing, so maybe I should be
> waiting longer.

I believe you need to be looking at a wider bandwidth than the K3 will 
provide, hence the the use of an SDR in the above suggested read.  It 
takes a few days to create the spectrograms, but they will show you 
EXACTLY what is happening on the entire band.

Thanks, and 73's,
Dave (NK7Z)
http://www.nk7z.net