OFDM is also what is used for [A]DSL, and, but at UHF, or SHF, digital
TV (terrestrial and satellite). It's also, at least in Europe, for
digital radio, at VHF. I think it is also used for 4/5G mobile. phones.
It is not intrinsically secure. It's main advantage is that it gets
close to the theoretical (Shannon) limits on error free bit rates in the
presence of purely Gaussian noise, and has good multipath tolerance (not
useful for ADSL, though).
Encryption isn't required. Scrambling may be done to avoid spectral
peaks, but actually encryption, if used, is done at a higher level.
--
David Woolley
On 08/06/2022 09:22, Dynolab wrote:
Your 24kHz spaced spurs from 6.6 MHz to 7.4MHz sounds very much like Orthogonal
Frequency Division Multiplexing (OFDM).
A secure type of modulation encryption that is often used on the HF bands for
High Frequency securities trading.
If it is a foreign source, they may not respect our 40 meter ham band
frequencies.
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net
This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com
