29MHz trans Atlantic DX...

[K0ZAK]

12-1-2022 Test with M0DTS_2.jpg (312.54 KiB) Viewed 3140 times

Rain has finally stopped here in Maryland and band conditions are starting to improve again. Rob's signals are all over the place today, but I did finally get some strong enough signals to get decoding again. Captured a few frames of video, but not any motion, before it dropped down in the noise again.

[g0mjw]

A little more success today.

2022-12-05_29MHz.jpg (1.44 MiB) Viewed 2823 times

But so far signals are a little weak and multipath is the problem again.

Mike

Edit - a bit later John managed to get about 10 seconds of video!

[radiogareth]

Conditions briefly good between me and the K3FEF KiwiSDR and I managed to record and decode myself
Gareth

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[K0ZAK]

Conditions were good on and off today. I tested got some decent semi sequential image decodes from G4XAT, then a few deccoded images from M0DTS, then the band folded a bit. It opened back up later and I was able to finally decode about 10 seconds of actual full motion video of G0MJW walking around his shack! So full motion is indeed possible with the right conditions! Unfortunately, I wasn't set up to capture that motion....

John Kozak; K0ZAK/3

12-5-2022 Test with M0MJW.jpg (344.45 KiB) Viewed 2776 times

[f1faq]

My first picture...
No call ?
Via KA1GXR (USA / MA)
Recorded on the WebSDR and played back in SDR Angel

Capt1.PNG (328.67 KiB) Viewed 2765 times

[g0mjw]

That's me - there was a call, it is in red but it seems to have blurred out.

Mike G0MJW

[G8JNJ]

Hi All,

I finally got my Low VHF KiWi Web sdr 0 - 62MHz on-line.

It's on a rural hill top in Dorset, and has a very low noise floor.

http://wessex.zapto.org:8075

The antenna is a 20m per side terminated delta loop. It's a bit of a compromise antenna on the Low VHF bands, but it works well enough up to about 40MHz, and it's certainly good enough for most of the stuff we have been hearing recently.

I have set it up with 3 receive channels, so that it can allow an I/Q bandwidth of up to 20kHz.

If you are more interested in just the 0-30MHz spectrum then, please use this co-sited KiWi instead.

http://wessex.zapto.org:8073

Both sdr's have an exceptionally good noise floor, and are probably among the best worldwide.

However, I'd be very interested to see how well they compare with your receive setup's.

Regards,

Martin - G8JNJ

[K0ZAK]

Here are a couple of screenshots on todays DVB-T test with G0MJW. pictures show 2 different SDR dongles, one feeding SDR# and the other feeding SDRAngel. Also feeding a Knucker RX with an upconverter, but It did not indicate that it was seeing anything at all. More work is needed here to confirm that the upconverter is working with the Knucker.

John, K0ZAK

[HB9DUG]

Dear All,

I have asked Edouard F4EXB to look at adding an option for a 20 kS/s sample rate (20250 S/s actually) as for now,the kiwiSDR plugin assumes always a 12 kS/s rate.

I will keep you posted of the status of my request.

73 qro de michel, hb9dug

The plugin has been updated and now select automatically the right sample rate. Merci à Edouard

[G8YTZ]

A warning to those using up/down converters (stay with me on this one!)

My TV repeater GB3JV transmits on 3.404GHz using DVBS-2. The transmitter consists of an SR-Systems HD Modulator that produces an IF signal at 404MHz and is followed with a Kuhne up-converter with an LO of 3GHz that produces the final output frequency at 3.404GHz. The modulator is set to spectrum = normal (as opposed to inverted) The symbol rate of the repeater output is 2MS/s

The receiver uses a Titanium or Norsat C-Band LNB with a LO of 5.150GHz, giving an IF of 1.746GHz. Note: the LO is above the received IF frequency.

All is well receiving this "inverted" spectrum on every receiver I have tried: Sony TV, Minitiouner (Serit Tuner) with Ryde and Minitioune software, GT Media Sat finder, Domestic satellite receiver. never a problem which way up the spectrum is...

However, when using SDR Angel's DATV de-modulator the constellation freezes and no decode is possible, however invert the spectrum of the transmitter so that the received spectrum is "Normal" at the receiver (due to the LNB inversion) then all is ok and SDR Angel decodes correctly with an almost instant lock.

Thinking about it the LO of your typical 10-12GHz LNB is always below the received frequency

Interesting observation that might help those having problems decoding some transmissions using SDR Angel - make sure that the Tx/Rx arrangement when using up/down-converters ensures that the received spectrum is not inverted. Perhaps (I've not confirmed this) this spectrum inversion limitation is not present with DVBS which is why some people say that DVBS-2 does not work on 29MHz?