29MHz trans Atlantic DX...

[G8YTZ]

Steve G4NZV suggested this fix and it works!

In the SDRangel Device select box press the 'X' then the IQ button to swap the IQ to QI [if you have an inverted spectrum]

[f5oeo]

My 5 cents ... (Christmas gift ?)
My pluto reports attr 6: frequency_available value: [46875001 1 6000000000]
Which means LO at minimum at 47Mhz. It means with a samplerate of (47-29)*2=36MSPS we can modulate directly dvbs2 on 29Mhz (SR max to 1MS).
Just a matter of NCO/mixer in software.

Of course, RX side is similar : it could be received directly (LeanDVB or SdrAngel). If you prefere minitiouner, pluto could Rx on 29Mhz make a transposition which Tx on L frequency.

73
Evariste F5OEO

[g0mjw]

Interesting. What does the spectrum look like? It is good enough to use on-air?

Mike

[G4GUO]

If anyone is interested these are back in stock

https://qrpblog.com/product/a600-hf-vhf ... ifier-kit/

[G4GUO]

FYI

I tried using a Ham it up nano https://www.nooelec.com/store/ham-it-up-nano.html to transmit convert from 154 MHz to 29 MHz.
(They work in both directions).
However, I couldn't get more than -28 dBm before the waveform started to get noticeable shoulders.

- Charles

[M0DTS]

The only non linear parts in the RF path is the RF switches for Bypass, they will likely be the culprit.
They could easily be removed!

Rob

[radiogareth]

Turned more DC into heat this afternoon having changed the fan on my PA for something with a LOT more airflow. Propagations different again with fading but not as frequency selective as before. up to 22dB above the noise on the Milford PA Kiwi SDR and John also decoded a few single frames.

29.15_11_01.PNG (534.66 KiB) Viewed 4674 times

Recorded a few strong bits so will try local decoding of them next.
Gareth

[K0ZAK]

I was able to decode a sequence of individual frames from Gareth this morning, but not enough to be called motion. Signals were up and down quite a bit. Was watching with two different RTL-SDR dongles, a HackRF one, and a Adalm Pluto with a Ham it up upconverter. The two RTL-SDR dongles & the HackRF One were decoding data, but the Pluto wasn't. Best decoding was done with the 'RTL-SDR Blog V3 R860 RTL2832U RTLSDR 1PPM TCXO SMA'

1-11-2023 Test with G4XAT_1.jpg (309.75 KiB) Viewed 4669 times

John
K0ZAK
Baltimore, Md. USA

[M0DTS]

A copy of my script for generating the Transport Stream for 18Ks DVB-S at 2/3 FEC at ~2frames per second.
It's not perfect but works well enough for testing.

Assumes original OBS virtual cam plugin, encoding from Nvidia graphics card and ffmpeg in c:\ffmpeg\bin\ folder.
You may have to tweak for other encoder methods.

https://www.dropbox.com/s/win7r7xr2chvm ... S.zip?dl=1

Rob

[radiogareth]

And if you don't have a suitable graphics card, I have a version that uses the Intel encoder which I'm running on an I7 V7 laptop. Just ask, I'm not 'git-hubbed up' and I'll email it to you.
Gareth