In general, most SA's have a very high noise figure. And a built in
whip is an inefficient antenna on 40 meters. So this "measurement" is
probably fairly meaningless. To get a meaningful measurement, you need
a combination of an antenna and a receiver that is sensitive enough to
hear noise off the air. For the antenna, I like to use a tuned loop
antenna. For a receiver ... well a real "communications receiver" (not
an entertainment device) with a noise figure below 10 dB. (turn on the
built in preamp). I like to use an Icom 706 running off a gel cell.
The off the air noise should peak as you tune the loop. (Do not use an
untuned loop with a preamp; you will only hear preamp noise, not off the
air noise).
---
Rick Karlquist
N6RK
On 2025-07-08 10:13, John Warren wrote:
> Has anyone in Texas installed whole house backup batteries from Base Power in
> Austin, Texas? I am considering installing their batteries and am looking for
> any insight on potentional RFI issues. My neighbors have their batteries
> installed and they were kind enough to allow me to take some rough
> measurements.
>
> I used a TinySA spectrum analyzer with the built-in telescoping antenna and
> did find that at the inverter enclosure for each battery there was around a
> 10 dB increase in noise from around 7 to 10 MHz and another similar peak in
> the area of 14 MHz. The noise level dropped quickly as I moved away,
> disappearing completely around 3 to 4 feet from the inverter enclosure.
> Around the other sides of the battery and conduit that connected to the
> house, there was no excessive noise.
>
> I plan on going back over with a portable AM/FM/SW radio and the TinySA
> again to make some better measurements and document what I find.
>
> Thanks for any input anyone may have.
>
> 73,
>
> John K5QX
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