[NLRS] Increase noise on 432

[Chris Elmquist]

On Wednesday (09/10/2025 at 07:24PM -0500), Dave Fugleberg wrote:
> Good point, Chris! Might be worth firing up a SDR and rtl_433 and see what
> decodes. I may very well be hearing my own wireless thermometer …

And-- it doesn't have to be a weather station or thermometer per se--
it can be an outdoor sensor for a heating system that may not have
any user viewable display. Honeywell HVAC controls, as one example,
use wireless temp+humidity sensors with a 433 MHz wireless link. So
someone may not even be aware that a wireless link is in use for that.
Check around for who got a new furnace because the control board inside
can use a 433 MHz link from a remote sensor.

Also, not applicable to Jon's issue but could be for others, there are
several weather stations, a LaCrosse model in particular I am aware of,
as I have one, that run on 915 MHz for the outdoor sensors.  So, you
could encounter issues on 902 with these.  I have not.  Mine seems to
keep to itself up on 915 MHz and is not so broad as to appear in 902 or
903 range.  But you never know how each one might behave.

Chris NØJCF

> On Wed, Sep 10, 2025 at 7:04 PM Chris Elmquist <chrise at pobox.com> wrote:
> 
> > On Wednesday (09/10/2025 at 11:03PM +0000), Jon Platt via NLRS wrote:
> > > Over the last few weeks I've noticed an increase in pulsed noise on the
> > low end of 432.  Tuning up to 433.900 MHz shows the usual crude there but
> > I've linked my 432.100 pulses to really strong & wide pulse around 433.900
> > that are hundreds of KHz wide.  Maybe LoRa stations?  I hear two closely
> > spaced fast duration strong pulses every 30 seconds that are very wide,
> > hundreds of KHz, like maybe a chirp .... LoRa?   I thought maybe its the
> > 1300 MHz radar that can be heard on 1296, but its not that.  Seem to be
> > unduly and nasty very wide signals.
> > > Any one else hearing this, especially as it appears as a pulsed noise
> > source with short duration on 432.1 ?
> >
> > I will do some listening here but the first thing that comes to mind is
> > someone nearby spinning up a new wireless thermometer or weather station.
> > These are supposed to be on 433.920 but use SAW resonators to do that,
> > and can be extremely broad and off frequency, and include lots of spurs.
> >
> > They are usually pretty low power so the guess would be that it is close
> > to you.  You might use your yagi's directionality to try to pinpoint a
> > particular direction it comes from.  If you can't isolate a particular
> > direction, then it's pretty close in-- maybe something new you acquired
> > or a very nearby neighbor did?
> >
> > 73, Chris NØJCF
> > --
> > Chris Elmquist
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-- 
Chris Elmquist