DATV-Express Project - December update report

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KenW6HHC
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Joined: Mon Jun 01, 2009 4:20 pm

DATV-Express Project - December update report

Post by KenW6HHC » Mon Jan 01, 2018 10:42 pm

Art WA8RMC reported great results with his first hand-soldered prototype unit using MiniTiouner-Express PCB blank boards. The prototype hardware unit is shown in Figure01 below. Art’s initial testing demonstrates a higher sensitivity value than any set top box he owns. WA8RMC thought his Geosun set top box unit that we use at the WR8ATV repeater was as good as it gets, but this one is better and more stable.
The Geosun set top box units display frequent pixelation at the signal reception threshold but the MiniTiouner-Express unit is quite stable at that point with no pixelation. But, if I reduce the signal level of either just one dB, they drop out of lock as expected. The signal level at which the cliff effect takes place on the MiniTiouner-Express hardware prototype is -94dBm reliably (when receiving a transmission with FEC=7/8 and an RF BW of 4.2 MHz), which is about 5 dB lower signal strength than when using his sensitive Geosun STB.

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Figure01 – Hand-soldered prototype using MiniTiouner-Express PCB with Serit NIM. The NIM lies flat underneath the PCBA.

The MiniTiouner-Express hardware unit is designed to run with MiniTioune software developed by Jean Pierre Courjaud, F6DZP. Jean-Pierre F6DZP has been modifying Digital-ATV receivers for DVB-S protocol with software for years (and recently also DVB-S2) - in order to allow the tuner to provide information that hams need. The main problems with commercial DVB-S receivers are (a) that if the signal is not good enough - they show only the “blank screen of death” and (b) they do not work with smaller Symbol Rates that some hams want to use. The MiniTioune receiver/analyzer software from F6DZP solves these two problems. Figure02 shows a screen-capture of WA8RMC’s transmission received via the ATCO clubs DVB-S on 1268 MHz using F6DZP’s V.0.6b software. {Three NOTES:
(1) The received signal from the WR8ATV repeater is from about 15 miles away through trees.
(2) The F6DZP software v0.6b being run with MiniTiouner-Express hardware does not yet recognize this hardware unit…hence Fig02 displays “NIM = SeritPro”.
(3) Jean Pierre F6DZP reports that the next version of the 'MINITIOUNE software that he releases, v0.8a - Receiver/Analyser DVB-S/S2 144 MHz to 2450 MHz - for MiniTiouner/ MiniTiouner-Pro/ MiniTiouner-Express', will correctly recognize the MiniTiouner-Express hardware.


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Figure02 – Screen-capture using F6DZP MiniTiouner v0.6d software being received from ATCO WR8ATV repeater (about 15 miles away)

WA8RMC’s intent is to produce a smaller and assembled and tested version of the Serit NIM PCBA design at an affordable price. The MiniTiouner-Express project team has decided to sell the MiniTiouner-Express hardware unit (with cover included) at US$75 plus shipping from USA (plus any applicable VAT). Art reports that he expects to robot-assemble the “first article” MiniTiouner-Express PCBA around January 05 and then begin testing.

Finally, Analog Devices appears to have delayed the next PLUTO Tx/Rx lot availability in order re-spin the PLUTO PCB. The PLUTO availability slipped out from 16 weeks…to 24 weeks ….see Figure03 from electronics distributor, Mouser USA.

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Figure03 – Screen-capture from electronic distributor, Mouser USA, on latest PLUTO-SDR Tx/Rx availability.

Charles G4GUO had spotted an Analog Devices explanation of the PLUTO availability delay in the release-notes of Analog Devices which described a circuit change in the PLUTO PCB to improve the PLUTO power-supply noise.


“Project speed set to slow” …. de Ken W6HHC

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