benson

sdr.hu is now REALLY closed for non-amateurs

benson

January 2020

An article in 'Janes Intelligence Review' last year certainly points in that direction. A snippet of that article can be found in the link below. Written by one of Jane's editors it might carry some weight.

link: https://www.janes.com/images/assets/042/83042/Software-defined_radios_point_way_for_simpler_direction_finding.pdf

sdr.hu is now REALLY closed for non-amateurs

benson

January 2020

One of those less well known but excellent alternatives is directKiwi created by llinkz.
(https://github.com/llinkz/directKiwi)

The program allows you to select any of the available Kiwi receivers on a… (more)

Noise at roughly 60 KHz intervals

benson

December 2018

In the addition to all the good points above another thing that might be worth checking is the coax cables going to your receiver. I replaced one low quality cable with poor shield and center… (more)

v1.246: GNSS Kalman filter, LED brightness control

benson

December 2018

Now that many more Kiwis are updated to V1.246 I do see quite a few more station that can be used for TDoA and some at good locations for multilateration.
Locally I noticed much improved position… (more)

GPS antenna trick

benson

January 2019

If your friend can have access to the roof of the building there might be better options. I had a similar situation in Taipei and managed to install an active antenna on the roof outside the view of… (more)

KYOTO News FAX 16969.1 kHz 23:00utc

benson

March 2019

Over at Techzone ( https://goughlui.com/2019/01/13/radio-radiofax-hf-fax-reception-on-kiwisdr-with-kiwifax-py/ ) there is series of blog posts with a lot of current info about HF fax reception in… (more)

Ionosondes

benson

April 2019

WA2ZKD wrote: seems like an extension for tracking one chirp TX could be possible (?)

I recently used some auxiliary programs to tune KiwiSDR (via Catsync) and tracking certain chirp sounders to see… (more) if propagation is open in parts of the HF spectrum. Even without using Chirpview these programs allow synchronising the Kiwi with the sounder visually by trial and error and although not giving precise propagation delays and signal strength still give a good impression which part of the spectrum is open towards a particular sounder. A short video recording is attached*.

Identifying those sounders remains a challenge like in the Chirpview days since the period & chirp time tables that can be found are all quite dated. I tried to use TDoA during stepper operation but usually only few usable points on the dt chart show up. The internet time delays probably wreak havoc not giving enough settling time for the remote Kiwis to be tuned to the stepped frequency. For the GPS locked sounders however the distance (path length) can be easily found using Chirpview.

Likewise using the audio chirps or beeps to create an ionogram from the sweeps would require a known time delay. For the TDoA project this was already determined. Generating ionograms might be possible on the Kiwi internally but internet connections show unpredictable and continuously changing delays. Using a PPS signal I measured 1.4 to 2.2 sec delays between Kiwi rx in and audio out using a PPS signal on a local network. As mentioned in the forum ionograms are already available from the large GIRO network showing the more modern DPS4D pulse sounders.

Three different programs were used that can step tune a receiver to follow chirp sounders. One (ref 1) tunes via a COM port output but is limited to 100 kHz/sec sweep rates and a 300 sec periods only.

The others I found (ref 2) are more flexible however tune either via a localhost or DDE interface via HRD (Ham Radio Deluxe). Still trying to figure out how to bypass HRD altogether and send the data directly to Catsync via a virtual COM port.

These steppers are not ideal and would need some modification in terms of interfacing, currently used sweep rates and sounder periods. Alternatively a frequency stepper could be built from scratch.

So who knows at some point if there is sufficient interest and after enough of the remaining chirp sounders are identified this could lead to a Kiwi extension where a particular sounder is identified via a drop down list.

ref 1 : https://www.qsl.net/pa1are/chirps.html
ref 2: http://www.m0dts.co.uk/?tag=HF

Best regards, Ben (less)

Browser session reset after 60 min

benson

June 2019

Thanks Powernumpty for your suggestions.

After connecting directly using an Ethernet cable between the Kiwi and a laptop the problem was still there.

Then upon closer inspection I noticed that in the… (more)

sdr.hu is now REALLY closed for non-amateurs

benson

January 2020

One of those less well known but excellent alternatives is directKiwi created by llinkz.
(https://github.com/llinkz/directKiwi)

The program allows you to select any of the available Kiwi receivers on a… (more)

sdr.hu is now REALLY closed for non-amateurs

benson

January 2020

One of those less well known but excellent alternatives is directKiwi created by llinkz.
(https://github.com/llinkz/directKiwi)

The program allows you to select any of the available Kiwi receivers on a… (more)

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benson

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sdr.hu is now REALLY closed for non-amateurs

sdr.hu is now REALLY closed for non-amateurs

Noise at roughly 60 KHz intervals

v1.246: GNSS Kalman filter, LED brightness control

GPS antenna trick

KYOTO News FAX 16969.1 kHz 23:00utc

Ionosondes

Browser session reset after 60 min

sdr.hu is now REALLY closed for non-amateurs

sdr.hu is now REALLY closed for non-amateurs