After tweaking my old Realistic DX-302 I was scanning the bands.
By chance I decided to listen at 13.560 mHz and what do ya know? I'm hearing some type of beacon.
This is a keyed carrier. About once per second it's on for about 200 msec like a time signal. It's just a carrier, not modulated, so you need to be in CW mode to hear the beep.
Pretty weak with some fading so it may be skywave. Hear it here first as unprocessed and then after noise reduction and normalizing:
So, I have a new signal to monitor. First time I've actually heard something on 13.560 mHz.
This evening around 1730 Eastern Daylight Time when I tuned in, the beacon was present. At 1749 it stopped.
A few minutes later it came and went a couple times emitting only a few beeps.
Then at 1803 I heard it but stronger and after a few beeps quit and then came back as well as a second beeper slightly different in frequency.
Right now at 1808 there is only one weak but steady beep.
I'll stream the audio at MRAM BEEPER BEACON so I can check it out from other locations.
I wanted to hear the streaming beacon from MRAM 1500, but I knew from previous experience that if I started the wrong process my fragile KDX radio stream which has Zara Driving Winamp could be completely overtaken by the introduction of a different stream.
Reminding the nearby mirror that I am an underappreciated genius, I smartly set things up so MRAM's beacon would use the VLC Player, leaving my Zara/Winamp concoction undisturbed.
I tapped on the ENTER and FLOOF, the MRAM beacon was going out over KDX Worldround Radio and my setup was smooshed.
The beacon sounded very much like a tone. With background crackling.
It took one-hour to figure out how to re-configure KDX and this time I'm saving the instructions in a known location.
Bring it on.
Yes, sometimes these systems simply take control but I'm sure you'll have it well in hand quickly.
I've been monitoring the frequency and it was active for well over an hour. At times there were two signals each the same format. But, its been quiet for a bit now.
I'll listen tomorrow.
Well, I heard the beepers again this evening around 8:00pm Eastern Daylight.
Sounded like two of them at first and ended with only one.
They weren't on nearly as long as yesterday.
Haven't heard the voices like yesterday. Hopefully I'll be at the radio so I can tune in on them.
No sooner did I save this post and they returned. Slightly offset from each other there are two of them about 500 cycles apart and occuring in turn one then the other.
Sounds like someone playing that old "Pong" game.
Guess I'll stay up a little longer and listen.
Checking at 10:11 am Eastern Daylight the signal is on. It stopped momentarily.
Same periodic carrier, on about 200 msec repeating at 1 second intervals.
West of your Ohio location, sitting near the Mississippi River in Missouri which executed a mentally disabled man at midnight, there is nothing being heard at 13.560MHz except fizzy noise.
If these signals are from a Part 15 activity then the sources are likely nearby. Maybe by direction finding you can get an idea of location and perhaps from this some notion of what they are.
Neil
As this frequency may be used for RFID tags and other scanning devices it could be a local commercial use.
The signal is to weak to receive on a whip antenna. I've been using my HF band dipole which is up in the air.
I'll have to see what I can do to DF the signal.
I have a spare WSPR beacon that I would like to put on the 13.560 mHz band. What would be the maximum power in dbm (or mW) that I could output into a vertical dipole assuming that the transmitting unit was at the center of the dipole (no coax). I can measure this power very accurately, but need to know more about the regulations that apply.
Many thanks,
Jim
W3BH
Saxonburg, PA
There are about an infinite number of solutions to this, but below is one set that generally might be useful.
The power needed at the feedpoint of this vertical dipole to just meet FCC §15.225 is about 3.35 mW, for these conditions.
Thanks Rich, I have the oscillator and this gives me a starting point for my output stage when I get around to it.
In the mean time the "beacon" I'm hearing comes and goes. Sometimes I hear a constant stream of data type noise.
I have taken the live stream mentioned above off-line. If it gets interesting again I'll put it back on-line.
Every so often I try 13.560 and usually hear nothing, but last night two things were observed.
First, I could hear a continuous sine wave deep in the noise that had no breaks, it just keep whistling, maybe about 1.5 kHz.
Suddenly the background noise popped way up in volume as if a nearby mobile transmitter was keyed on and was swamping my receiver. Just as abruptly the noise went to normal, until once more it was keyed up and then off.
Might have been a UPS truck, taxi, police, ambulance, FCC inspector, low flying drone, HAM operator, CB radio, old-style cordless phone, DHS, NSA, TSA, FBI, CIA, Mexican Drug Cartel, TV remote truck, fire department or NASA.
I'll try again tonight.
here is a website and forum that deals with part 15 beacons on lowfer and hifer
Many thanks Rich,
That's just what I needed for a power analysis of my WSPR beacon.
Appreciate it.
Jim