hi Kirt. appreciate the. response
I’ll try to take a stab at the questions you asked…
the freq range was. 440-449.
mode FM
types of receivers, Commercial moto or kenwood mobile radios, also various
brands ham HT’s
antenna used mobile dual band diamond, ht’s. =rubber duck
areas. were. as mentioned. as it was all over. i didn’t find a place w/o the.
noise. i don’t have the ability to really drive around. and denote a block that
might be rf quiet vs a block that is noisy. as it is all over a vast area.
I can try to make some recordings. in a day or so, but not sure how/where i
can post them
strength was normally s9
did i have electronics. on me, == they were removed. for testing noise
persisted i’ve not heard this noise. anyplace. else. but it’s so wide spread
n prevalent. in this s fl. region i am positive someone must know what it is :)
I have not tried to listen. around 434
am new here so can’t say if there are any radar like. set ups.
happy to provide any info. i think i covered all your questions. happy to
provide more info. and. can make a recording soon if you can suggest where i
can upload it
again , thanks so much for responding. the noise is annoying. for sure but am
also curious what it is and if it is ‘legal’ or not.
thoughts??
thanks
ml
> On Oct 18, 2021, at 6:50 PM, KD7JYK DM09 <kd7jyk@earthlink.net> wrote:
>
> Like you said, someone may already know, if you hear it, someone else may
> hear it. If so, that's awesome. If not...
>
> Lets start with exact frequency (ies), or overall range, then reception mode,
> type of receiver, antenna used, power source, and if wide spread, if possible
> to what extent, a square mile, 20 square miles, limited to specific areas?
> Is it stronger at any particular spot? Get some recordings to provide to
> some persons direct as they can't be passed through the list.
>
> Some will say RFI can't be ID'd by description, or sound, but those that have
> been around, or even just heard a few types, can do just that, as most RFI is
> unique to a large extent. A switching mode supply is unique, the model number
> of consumer garbage it's installed in isn't, but nobody will ever confuse it
> with the ignition system in a car, or even a power line or wireless weather
> station, so a thirty second recording can rule out literally billions of RFI
> sources across the US.
>
> It may be local to you, may even be your own receiver, or power source, or
> what you're using to move around to hear the signal all over the place. Have
> you heard the signal on foot, with a battery powered receiver, away from
> everything? To rule out a receiver, have you heard it to the same extent
> with an entirely different receiver and different power source?
>
> Do you have any other electronics on your person at the time? I've heard
> mobile phones, WiFi, Bluetooth, digital cameras, MP3 players, near-field
> devices, like contactless payment devices, and transponders, the type of
> stuff a person may normally carry. Even a digital recorder I used to use
> wiped out a large frequency range from HF to UHF, so I use an analog cassette
> recorder to document RFI.
>
> You did mention 440. Any chance you are listening around 433/434 MHz? If so,
> there is an ISDM (industrial, scientific, data, medical) band there, and you
> will hear noise/telemetry, pretty much everywhere around those frequencies,
> pretty much anywhere in the US. The devices are supposedly limited to 300',
> but I hear them miles from the source, even so far out in the desert, or
> hills, sources can't be seen.
>
> Any radar installations in your region? 440 is also a military radar
> frequency range, and I sometimes get blasted. The PAVE/PAWS system on the
> west coast, for example, operates from 420-450 MHz, and wipes out
> individuals, repeater, links, you name it, and I even hear it direct a few
> hundred miles east of it on occasion. From the late 80's to late 90's,
> 420-430 MHz in southern california was often affected by several radar
> systems.
>
> Any extra information can help.
>
> Kurt
_______________________________________________
RFI mailing list
RFI@contesting.com
http://lists.contesting.com/mailman/listinfo/rfi
|