Re: Mystery mode


Duration, frequency spacing, and any modulation (probably PM of some sort) would be interesting. Post processing to pull out relative timing and the like can also possibly pull out modulation using wide band USB.


On 20220709 14:14:56, Ken Sejkora wrote:

Thanks jdow.  I’m pretty confident that this is likely some ‘relatively new’ government/military communication mode, and most likely encrypted.  Trying to demodulate and decrypt the signal(s) is beyond what I’d try to do.  I was just curious as to what insights other users might have.  My point about recording them and looking at the waveform was more to the point of trying to see if the ‘pips’ on a given discrete frequency block are pure CW, or somehow modulated, but if they are very short in duration, that might be hard to determine.


As for location, I’m in SE Massachusetts (Cape Cod), so there is no shortage of potential sources within ±40-miles, such as multiple Raytheon and General Dynamics development labs, Navy facility near Newport, RI, submarine bases in Groton, CT and Portsmouth, NH, etc.  However, I’m guessing the origin might be more distant, perhaps one ionospheric skip, but hard to tell.  Kriss up in New Hampshire has also reported them.  Although he’s only ~93 miles away, it seems unlikely we’d both hear the same ‘local’ source on ~15 MHz.


Next time I notice them, I’ll try to get onto the Kiwi receiver network to select multiple receiver sites to se where else is ‘seeing’ them at the same time I am.  That might shed a small modicum of light on where the signals are coming from.


Thanks for your insights.  Have a great weekend. 73




From: jdow
Sent: Saturday, July 9, 2022 02:06 PM
Subject: Re: [SDR-Radio] Mystery mode


Roughly speaking where are you located? Are there military or protest sites anywhere near you? That definitely looks like some form of covert comm.


Join to automatically receive all group messages.