HF data using 3 (maybe more) freq

M0TAZ

This may have been discussed before (sorry if it has) but its the first time I have noticed it. TDoA was vague, could have been midlands UK maybe Tamworth area?
The sequence was data on 1 then 2 then freq 3 (mostly in that order) for 30 seconds or so, then pause, then repeat.

Any ideas
Dave
M0TAZ

G8JNJ

Hi Dave,

See

http://forum.kiwisdr.com/discussion/comment/2631#Comment_2631

NVIS makes a real mess of TDoA on the LF bands.

You may have to try TDoA at a few different times if day, before you find stable propagation.

Regards,

Martin

M0TAZ

Thanks, I think I nailed it now, seems to be on the South coast not too far from Weymouth / Bournemouth area been going all day hopping over 3 freq. TA

G8JNJ

Hmmm, not much out that way.

I know St Eval and somewhere in France had been used as test sites, but Blandford and Southwick (Portsmouth) are other possibilities.

Regards,

Martin - G8JNJ

G8JNJ

Hi Dave,

I've just managed to perform four runs using different KiWi's (fortunately Emerald was available.

I used the widest I/Q filter bandwidth to straddle two sets of databursts that had no other transmissions at low level in the background.

The best (narrow red band) 'pairs' of plots from all four runs intersect St Eval and the composite best guess location is just off the West Cornish coast in the Irish sea.

Regards,

Martin - G8JNJ

M0TAZ

Thanks, Martin, very interesting.

G8JNJ

Should have said, these are the bursts centered on 4785KHz

See

http://www.hfindustry.com/meetings_presentations/presentation_materials/2017_sep_hfia/presentations/THALES_HFXL_HFIAsept2017_Presentation_final2_Bernier.pdf

Regards,

Martin - G8JNJ

i56578

hi, take a look here
https://i56578-swl.blogspot.com/2018/09/psk-8-bursts-at-inconsistent-12800bps_19.html
http://i56578-swl.blogspot.com/2018/11/8-ary-constellation-bursts-at-12800bps.html

73
Antonio

WA2ZKD

The Thales scheme is quite different from the MIL-STD, Harris and Rockwell schemes.