DATV-Express efforts remained slow in April
Art WA8RMC has been testing a 64-bit version of draft DATV-Express v2.04 deb file that was built by Charles G4GUO. The main changes planned for v2,04 are:
(1) extend the range of PID values (correct PID MSB masking bug)
(2) add sin(x)/x compensation to improve the OFDM waveform used in DVB-T protocol (suggested by Ron Economos W6RZ)
(3) a few minor fixes involving UDP support
(4) support for Hauppauge HD-PVR encoder
So far his testing has gone well and for the first time, Art is able to use the DATV-Express to transmit to the WR8ATV DVB-T repeater…because the PID values can be set to match the default values used by HiDes UT-100B transmitter. Art encountered two lessons about DVB-T during the testing:
(a) First, DVB-T requires a higher signal-noise ratio to be received at the WR8ATV repeater than when using DVB-S protocol. Art has to crank up the power at home higher (with resulting large spectral regrowth “shoulders”) in order to hit the repeater. This overdriving of the amplifier is not good but a lower signal level won't make it.
(b) Second, the HiDes HV-110 receiver used for DVB-T at the WR8ATV repeater is NOT very “robust” for an unattended repeater. Art really doesn’t like this HiDes receiver and recommends “….. Don't put it in unattended repeater service. Had to go there to the repeater and manually reset the HV-110 again”.
Art still needs to finish all the planned testing on the 64-bit v2.04 software.
It turns out that Art really wanted the ODROID version of v2.04 for his home station instead of the 64-bit version. Since Charles G4GUO can not build and test reliably with his set-up on ODROID…Ken W6HHC switched gears. Originally Ken was going to first build the 32-bit version of v2.04 deb file…but instead started to build a deb file for ODROID U3. After six months, Ken was a “bit rusty” on building with QT5 and with debreate. Finally, Ken was able to successfully build a v2.04 draft version of deb file for ODROID using debreate package builder. One secret to good testing of a deb file is to NOT install it and test on your development system….but try to install and test on a “fresh image” of the operating system (without all the development tools present). So Ken has now regression tested the v2.04 deb and tested that that the extended PID values work fine on ODROID U3. The remaining tasks before releasing v2.04 for ODROID are:
1) Start the UDP feature testing without Express_Server
2) Then start HD-PVR testing (plan to order Hauppauge model 1228 “blue ring” this weekend on e-bay.)
3) Then plan to test UDP testing using Express_Server
4) Then plan to update User Guide for ODROID
Charles G4GUO has been testing streaming video from the Logitech web camera connected on a Windows PC using VMIX and sending the IP stream to the ODROID running a DATV-Express exciter. The MPEG2 encoder codecs come from the Hauppauge WinTV CD-ROM (although no Hauppauge encoder is actually installed). Also, he has been receiving IP streams via WiFi to a iPhone loaded with VLC.
Art WA8RMC will soon be off the Dayton HamVention to demo ODROID with DATV-Express.
"project is set to slow speed"....de Ken W6HHC
DATV-Express Project - April update report
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DATV-Express Project - April update report
Last edited by KenW6HHC on Tue May 05, 2015 1:59 pm, edited 1 time in total.
Re: DATV-Express Project - April update report
For those of you that don't read my blog http://www.g4guo.blogspot.co.uk/
I am currently investigating the Lime LMS6002D / Xilinx 7020 Zynq combo as a possible next generation
DATV transceiver. Lime have recently dropped the one off price of their chip from $110 to $35
http://www.limemicro.com/blog-2/lms6002 ... -adoption/
The LMS7002M would be a better alternative as it operates down to 100 KHz but it is too pricey.
The Lime chips pretty much remove about 1/2 of the parts needed on the Express board
and throw in a receive channel as well. They also have another device the LMS8001 in the
pipeline that has a claimed frequency range of 100 KHz to 12 GHz!
http://www.limemicro.com/products/
The Zynq chip from Xilinx combines FPGA fabric and a dual core ARM Cortex A9 device in a single package.
Again the prices of boards based on this chip are starting to come down too.
http://www.myirtech.com/list.asp?id=502
I am not too familiar with Xilinx parts so there is a lot of work involved getting up to speed in using
Vivado and their Linux environment PetaLinux.
- Charles G4GUO
I am currently investigating the Lime LMS6002D / Xilinx 7020 Zynq combo as a possible next generation
DATV transceiver. Lime have recently dropped the one off price of their chip from $110 to $35
http://www.limemicro.com/blog-2/lms6002 ... -adoption/
The LMS7002M would be a better alternative as it operates down to 100 KHz but it is too pricey.
The Lime chips pretty much remove about 1/2 of the parts needed on the Express board
and throw in a receive channel as well. They also have another device the LMS8001 in the
pipeline that has a claimed frequency range of 100 KHz to 12 GHz!
http://www.limemicro.com/products/
The Zynq chip from Xilinx combines FPGA fabric and a dual core ARM Cortex A9 device in a single package.
Again the prices of boards based on this chip are starting to come down too.
http://www.myirtech.com/list.asp?id=502
I am not too familiar with Xilinx parts so there is a lot of work involved getting up to speed in using
Vivado and their Linux environment PetaLinux.
- Charles G4GUO