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

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

Hi John,

This week I've been trying to use a number of KiWis to perform some antenna field strength measurements, but its been a somewhat frustrating process.

So I'd also like to echo Jim's request for an option to allow the the S-meter logging period to be even slower, perhaps up to 24hrs, so that I could also use it to monitor changes in my noise floor, signal levels from BC stations and other propagation related monitoring.

It's currently a real pain to have to derive this information from the graph image and the subsequent visual resolution is only about 3dB or so, it's also difficult to check for max values over a period of time or try to determine the signal average level. I know there is already a request to provide this functionality, but I also know that there are more pressing or higher priority fixes to be implemented first.

I wondered if it would be possible to add a function to store and be able to download the graphed dBm values as a CSV file. Each value to be timestamped and the header to the contain frequency and RX bandwidth.

This would permit much more detailed off-line analysis of max /min values, averages and other trends, which wouldn't need to be added to the existing graphing option. Maybe sampling intervals could be defined or automatically selected as a function of logging period so that huge files are not generated. Each time the S-meter restarts the file could be overwritten, perhaps a bit like the fax image files ?

Regards,

Martin - G8JNJ

Hi Dave,

There has been speculation on the UDXF@groups.io forum that it's associated with test transmissions from the Frankfurt area associated with High Frequency Financial Trading. It's also been heard just below 15MHz and moves around a bit.

If you are interested in'strange, signals it's worth joining UDXF just to get access to their logs of signals heard.

Regards,

Martin - G8JNJ

@Lonecrow

"That diagram there - the chokes are "as needed" right? Or do you need 2 for sure? Those brown lines above the "ground" symbol. What are they? Thinking of how I could ground coax without making another cut."

Yes the 'chokes are as needed' you will reach a point where adding more makes little or no difference.

The brown lines were meant to indicate the noise level being carried on the outer of the coax screen gradually diminishing as it gets closer to the actual antenna.

The three stepped horizontal bar symbols are ground connections and meant to indicate the addition of earth rod's, which like the chokes are "as needed".

You can ground coax by carefully stripping back the outer insulation and tightly wrapping some wire around the screen (if it is copper and you can very quickly solder with a hot iron even better) then tightly wrap the connection with some self amalgamating tape and cover with normal PVC insulation tape for a water and UV resistant joint.

I hope that now makes a bit more sense.

Regards,

Martin - G8JNJ