[TowerTalk] noise profiles...

[jimlux]

On 1/10/17 6:37 AM, Patrick Greenlee wrote:
> The typical offending grow lamp is a commercial item that doesn't meet
> the FCC requirements for a residential item. Some of the big box stores
> have sold the commercial models (noisy as all get out) without informing
> the buyer.
>
> So maybe a carrot could be offered instead of or along with the stick.
> When dealing with a grow light user you might mention there are
> residential grow lights that do not  S C R E A M  their presence in the
> RF spectrum and make it difficult to detect their use whereas the
> commercial ones are  easy to radio locate by the authorities should that
> be of interest to the owner/user.  Then there is a potential code
> compliance issue.  The commercial units are not intended for residential
> use.
>


HF noise related, so I guess it's on topic, although maybe this might be 
better for the RFI list...

I was looking into the idea of using a RFI detection system on a UAV for 
scanning neighborhoods for hot spots...

Law enforcement doesn't use RFI detection as a way to detect grow 
operations - they *might* use it after having a warrant, but if they 
have a warrant, an easier way is to look at the power consumption on an 
hour by hour basis, which in most places these days they can do with a 
simple request to the utility.

In the United States, it's not really legal to just do broad band 
spectrum surveys for the purposes of detecting illegal activity.  The 
FCC, in its spectrum management role, can do such surveys to locate and 
identify an RFI source, but in response to a complaint.

The basic rule is that law enforcement cannot use technical means that 
are not "commonly available" (thermal imaging, radar, spectrum 
analyzers) without a warrant.  Obviously, there's a fair amount of 
parsing what "commonly available" means - in the case of Kyllo, it was 
thermal imaging used to detect the excess heat from the grow operation. 
What is normal for a ham (a spectrum analyzer) would probably not pass 
the "commonly available" test - it's the combination of sensor cost and 
expertise in interpreting, etc.  So as a result, LE isn't going to use 
it - they're rather have a nice iron-clad bust than spend time arguing 
exclusionary rule, etc.

For what it's worth, the power company does NOT look for this either, 
and report to law enforcement - they only do it when asked, with a 
warrant.  The utility's point is that they have employees out in the 
field who are exposed to potential bad guys, and they do not want their 
service people being perceived as potential cops.  Nope, they rather 
have some clerk in a call center respond to the inquiry with a data file 
of kW vs time and let LE make the decisions.

The utility will get involved if there's a "theft of service"  - if you 
have high consumption, and all of a sudden it goes to zero, then they're 
thinking that someone might have bypassed the meter.  That's a crime, 
and the sudden drop is a reason to have someone go take a look (are 
lights on, and there's no movement on the meter?).  After that, then LE 
can go get a warrant because there's probable cause to investigate for 
electricity theft (and safety issues).  And, if they go in and happen to 
see a grow operation that's illegal (not all grow ops are illegal these 
days.. maybe violating zoning or business licensing, but in many states, 
it's legal to grow stuff).



take home message - make your field strength measurements and complain 
to the FCC - they're the ones who enforce Part 15.