DATV-Express Project

[KenW6HHC]

Art WA8RMC is preparing for a production build of a new version of MiniTiouner-Express units called “Rev B”. The small design change allows a push-on jumper to select either (a) allow external power supply to feed voltage to the board and any LNB or (b) to have the hardware unit powered by the 5V on the USB-3 cable. The shipment of 100ea Serit tuners is expected to arrive around October 10. The world-wide inventory of remaining “Rev A” units is quite low…and might run out before the newer units are assembled and fully tested.

Charles G4GUO has fixed one bug for PLUTO units with the v1.25LP10 software release. One user of the v1.25LP10 software (John G4BAO) discovered that there is a coding design problem with the LimeSDR-USB and LimeSDR-mini units. With LimeSDR-USB units, if frequency selected is <2.0 GHz, then then code did not select the correct output port and the RF power output was too low. With LimeSDR-mini units, if frequency selected is >2.0 GHz, then the code did not select the correct output port and the RF power output was too low. Charles has prepared a new v1.25LP11 of the software and Ken is getting ready to re-test at his lab and then prepare for this new release to be uploaded to the www.DATV-Express.com web-site.

Ken W6HHC has prepared a new Block Diagram that illustrates that the DATV-Express software now supports four different hardware boards.


Block Diagram of DATV-Express software supporting four different boards.

Ken plans to update the DATV-Express User Guide to emphasize that DATV-Express has transitioned to become solely a software product for the future.


During September, Tom WB6P completed the gerber artwork for “Rev B” of the MiniTiouner-Express printed circuit board. The artwork and other PCB files have been sent to the PCB-house for fabrication. .

Project Speed is set to slow….de Ken W6HHC

[KenW6HHC]

Just a note that the DatvExpress v1.25LP11 software for selecting and controlling the four different exciter board models has now been successfully uploaded as a zip file to the DOWNLOADS page on the www.DATV-Express.com website.

As a side note: while testing the v1.25LP11 software I came to realize that I did not have test equipment in my home lab to measure RF power (easily) at >2.0 GHz. My trusty Rigol DSA815 spectrum analyzer only measures up to 1.5 GHz. So I had to rely on the v1.25LP11 testing performed by Charles G4GUO and John G4BAO with the LimeSDR-USB and LimeSDR-mini boards at >2.0 GHz.. Download the NOTES_v1.25LP11.txt file to understand the details on the power-out-level issues when running with the LimeSDR-USB and LimeSDR-mini boards.

73...de Ken W6HHC

[VK5YYY]

Hi DATV-Express Project Team

I would like to run Lime Mini at 5msym 8PSK
Clearly my old PC can't do it, other PCs tested haven't done much better, between 2-3Msys it gets ordinary
VK5BD could run the original lime with old software and old I3 PC when the software came out and achieved that speed

Could someone please give me guidance on an approximate or minimum spec of the PC required
Is it more cores, faster clock, faster ram, ssd, Win 7,8.10, 32 vs 64 bit etc .... that contribute most the higher Msym
Or is it possible the current version of software needs fine tuning, or hasn't been tested or designed for that speed using Lime Mini
In which case the latest PC won't help

Tomorrows test will be a high spec gamer PC see how that goes
Any advice gratefully accepted

Cheers Roger VK5YYY

[G4GUO]

I hope you are using USB3

I just tested it on my i7-6700K 32G of DRAM and it can easily do 5MS/s 8 PSK H.264 with about 12% CPU

I wound it up to 5M 32APSK and the CPU increased to 13%

- Charles

[G8GKQ]

Roger

I suppose the inevitable question (from a UK perspective) is: Why do you need to run such a high SR? Is your video source that high res/fast motion that it needs almost broadcast-quality HD bandwidths?

I'm intrigued

Dave, G8GKQ

[VK5YYY]

Hi Dave and Charles

Here's a post from last year of the repeater we built viewtopic.php?f=79&t=5104&p=13323#p13323
You can input SD or HD, DVBS, S2 any FEC or PIDs the Strong box doesn't care, the output is DVBT 720P, it works great, looks superb!
There is so much great HD material out there promoting Amateur Radio, 3 of us broadcast 1080 and 2 SD for an hour 5 nights a week at 7pm
Programs like Ask Dave, ElectroBoom are staples with the kind permission of the Authors and the weekly Wireless Institute broadcast
as Audio with Text, other news/local activities are broadcast and we broadcast the monthly meetings/field activities
HD is good because you can see fine text from lectures, tutioune looks great and we broadcast to each other our latest projects
Ratings sometimes are 5 or 10 viewers, with call back after
The C920 camera looks LOVELY at 5Msym H264 through the repeater (your finest hour Dave)

Reduced Bandwidth hasn't taken off here, there is only 3 or 4 Portsdown (derivative) devices in South Australia I know of
VK5BI came up from Adelaide with his a few weekends ago and made a 97km contact across the Gulf
I've tried to promote Portsdown-under, the HF brigade don't get it, but they will watch Ham related broadcast material
We can't use 6 Metres or 2 Metres TV here in VK, we do have 7Mhz on 70cm and truck loads of spectrum at 23cm and above, so 5Msys it is

Thanks for the feed back Charles I've wanted to buy a new PC, but didn't seem much point if the software couldn't do it (yes we used USB3)
We since tried a AMD Risen 8 core PC which was fine, but that's a Ferrari and maybe we only need a Vauxall
Vmix wouldn't run smoothly, GOP problems maybe?
I did wonder if someone might know which aspect of the PC is important: to get best bang for buck...speed/ram/cores???
The only safe thing to do is to take the bitter pill and stump up for a high spec PC

Cheers Roger VK5YYY

[G8GKQ]

Thanks Roger

That explains it.

Interestingly enough, at 5 MS, the C920 is only using half of the available bandwidth. They have done a really good job with the H264 compression on that camera! (Them, not me - I just did some pipework for their signal and recombined the audio...)

73

Dave

[KenW6HHC]

Art WA8RMC reported he picked-up and tested the “first articles” of MiniTiouner-Express unit’s design called “Rev B” from the assembly house. All units fired right up…although one unit needed to have the USB-chip solder refluxed. Art observed that he observed some voltage drop at the end of the USB cable plugged into the computer USB-3 port. Use a short USB cable if you plan to obtain power from a USB-3 port using the new jumper. Quality brand USB-3-grade cables are not longer than 2 meters and are recommended.

New RevB of MiniTiouner-Express with arrow pointing to the new J3 jumper set-up that was added. The push-on shorting plug is shown positioned (away from end of the board) to configure power supplies as the original design (not USB-3 powered).

It important to note that the new RevB units will ship with J3 configured to work like the original design.

The photo below is the Fuji “pick-and-place robot” for SMT PCBAs. The PCB panel-array is designed to hold six boards. The assembly house started to complete the rest of the 100 unit production run on Friday, Nov 02.

The fast FUJI “Pick-and-Place” robot can complete each unit in 5 seconds, 30 seconds for the PCB-array of six boards.


Charles G4GUO had fixed one bug for PLUTO units with the v1.25LP10 software release. v1.25LP11 of the software was released to the www.DATV-Express web site DOWNLOADs page after Ken independently tested at his lab. No new problems have been reported with v1.25LP11. Charles did say he also improved his GPU LDPC decoder using a modification to the algorithm he read about in an academic paper.

Ken W6HHC Plans to upgrade the MiniTiouner-Express User Guide to include the new power supply options available with the addition of J3 in RevB. Ken is also working to update the DATV-Express User Guide to emphasize that DATV-Express has transitioned to become solely a software product for the future.


Project Speed is set to slow….de Ken W6HHC

[G4GUO]

If anyone is interested the improvement to my GPU LDPC decoder uses the Self Corrected Min-Sum algorithm.
https://arxiv.org/pdf/0803.1090.pdf
It improves decoder performance by about 0.4 dB

- Charles

[F4HSL]

Hy Charles,
Thanks a lot for your DATVExpress software. Anyway I have some problems...I have tested it with a PC windows (core i7) 10, up to date with Pluto and lime sdr mini.
No major problem with Pluto. With Lime mini, connected in USB3, latest drivers, the board is often not recognised by the software, I have to relaunch, to disconnect the board, trying again and so on, and sometimes it is not working at all and I have to reboot windows. The dialog between the board and the software during initialisation seems to be very slow (ie when I do a parameter modification in the software I have to wait quite a long time compared with the Pluto). However when it works it is fine. Seems to a mismatch? Drivers problem ? Any idea ?
Best 73’s
Yves (F4HSL)