CW Stn on 4088.5 KHz

[cwguy]

Not sure if this is the right place (I don't want to look like a noob)

Been looking at some online SDRs lately, and this morning seeing/hearing some cw on 4088.5 KHz.  Seems to be a one way transmission (not a qso) - seems to be repeating lines of code, always starting with N3N.

"N3N UA56D3 6NU5DN4 AA3 36"
"N3N UA56DD 74U6UU5 AT5 5N"  and so on.....

Always starts with N3N, and ends with what seems like a sequence number, like 36, then 37 - just now heard 4N instead.

Some fades, so I can't vouch for the accuracy.  About 20 WPM.  I dialed up an SDR in Ft. Collins, CO and was copying it pretty ok there too at the same time as the KPH SDR in CA.

Thoughts anyone?

[Token]

The real frequency is 4089.0 LSB.  Yes, it is CW, however it is a 500 Hz modulated tone CW being sent in LSB mode.  You can tell because in addition to the CW on 4088.5 kHz you also see audio harmonics on 4088.0, 4087.5, 4087.0, etc.  In the past I have seen this station use the same technique in USB and AM, as well as SSB+carrier.  I have also seen it in honest ICW, keyed carrier, CW.

The station is thought to be part of a Chinese air defense network, and is sometimes called MC03.  A description can be found on page 27 of this document http://www.numbersoddities.nl/Chinese-military-nets.pdf

While it seems improbable, in this day and time, that stations like VC01, VC03, and MC03, could be part of an actual military network, after all they seem so old school, once you get over that preconceived bias the possible answers become few, and such a military network starts to rise to the top as an answer.

T!

[cwguy]

Just rediscovered this again this morning at 1547 on the KPH SDR (I forgot about my initial post!) - thanks for the info Token, and yes, I do see the audio harmonics.  Thanks for pointing that out.

[Josh]

"While it seems improbable, in this day and time, that stations like VC01, VC03, and MC03, could be part of an actual military network, after all they seem so old school, once you get over that preconceived bias the possible answers become few, and such a military network starts to rise to the top as an answer."

The reason for Chinese and Russian military use of hf cw is they want their radio ops to be fluent in cw and the vagaries of hf before the big one starts. They know the sats and land based telecom switching centers will be the first targets to be hit (kinetically or electronically) in any real global conflict.