drmpeg (u/drmpeg) - Readit News

drmpeg commented on Time Station Emulator github.com/kangtastic/tim... · Posted by u/FriedPickles

This is pretty darn cool, but I have to say I was somewhat let down by the WWVB signal. I was expecting the entire audible range instead of simply the extracted data. That being said, that's also really darn cool.

I find the WWV/WWVB droning soothing somehow.

drmpeg · 17 days ago

Here's an emulation of WWV I did with a transmit capable SDR.

https://www.youtube.com/watch?v=9LsJn0CyyZI

drmpeg commented on Television is 100 years old today diamondgeezer.blogspot.co... · Posted by u/qassiov

chasil · 18 days ago

I had a communications theory class in college that addressed "vestigal sideband modulation," which I believe was implemented by Farnsworth. I think this is a critical aspect to the introduction of television technology.

https://en.wikipedia.org/wiki/Single-sideband_modulation#Sup...

drmpeg · 18 days ago

VSB came later. From https://www.tvtechnology.com/opinions/hdtv-from-1925-to-1994

In the United States in 1935, the Radio Corporation of America demonstrated a 343-line television system. In 1936, two committees of the Radio Manufacturers Association (RMA), which is now known as the Consumer Electronics Association, proposed that U.S. television channels be standardized at a bandwidth of 6 MHz, and recommended a 441-line, interlaced, 30 frame-per-second television system. The RF modulation system proposed in this recommendation used double-sideband, amplitude-modulated transmission, limiting the video bandwidth it was capable of carrying to 2.5 MHz. In 1938, this RMA proposal was amended to employ vestigial-sideband (VSB) transmission instead of double sideband. In the vestigial-sideband approach, only the upper sidebands-those above the carrier frequency-plus a small segment or vestige of the lower sidebands, are transmitted. VSB raised the transmitted video bandwidth capability to 4.2 MHz. Subsequently, in 1941, the first National Television Systems Committee adopted the vestigial sideband system using a total line rate of 525 lines that is used in the United States today.

drmpeg commented on Level S4 solar radiation event swpc.noaa.gov/news/g4-sev... · Posted by u/WorldPeas

drmpeg · 25 days ago

Although everyone is interested in visible aurora, the proton flux is also really impressive. It peaked at 37,000 pfu at 1910Z. The highest ever recorded was 43,500 pfu in March 1991.

drmpeg commented on More than one hundred years of Film Sizes wichm.home.xs4all.nl/film... · Posted by u/exvi

drmpeg · a month ago

VistaVision has made a comeback with "The Brutalist", "One Battle After Another" and "Bugonia".

https://en.wikipedia.org/wiki/VistaVision

drmpeg commented on When square pixels aren't square alexwlchan.net/2025/squar... · Posted by u/PaulHoule

m132 · a month ago

>Before HD, almost all video was non-square pixels

Correct. This came from the ITU-R BT.601 standard, one of the first digital video standards authors of which chose to define digital video as a sampled analog signal. Analog video never had a concept of pixels and operated on lines instead. The rate at which you could sample it could be arbitrary, and affected only the horizontal resolution. The rate chosen by BT.601 was 13.5 MHz, which resulted in a 10/11 pixel aspect ratio for 4:3 NTSC video and 59/54 for 4:3 PAL.

>SD channels on cable TV systems are 528x480

I'm not actually sure about America, but here in Europe most digital cable and satellite SDTV is delivered as 720x576i 4:2:0 MPEG-2 Part 2. There are some outliers that use 544x576i, however.

drmpeg · a month ago

Here's some captures from my Comcast system here in Silicon Valley.

https://www.w6rz.net/528x480.ts

https://www.w6rz.net/528x480sp.ts

drmpeg commented on When square pixels aren't square alexwlchan.net/2025/squar... · Posted by u/PaulHoule

drmpeg · a month ago

> Videos with non-square pixels are pretty rare...

Before HD, almost all video was non-square pixels. DVD is 720x480. SD channels on cable TV systems are 528x480.

drmpeg commented on Ask HN: What skills do you want to develop or improve in 2026? · Posted by u/meridion

throwaway2037 · 2 months ago

    > Become conversational in Ukrainian.

This one caught my eye! What is your motivation?

drmpeg · 2 months ago

There's some thought that Ukraine could become a tech hub after the war due to their drone technology.

drmpeg commented on Ask HN: What skills do you want to develop or improve in 2026? · Posted by u/meridion

ChuckMcM · 2 months ago

I'd like to get a full QPSK based OFDM modulator/demodulator implemented in an FPGA. Means improving my Verilog skills, my FPGA tool familiarity, and really understand how to implement OFDM modulators.

Create a blog and post at least 8 times to it over the next 12 months, which would be improving my skills with writing and illustration.

Design at least two boards and get them through the prototype stage into bringup and running.

Become conversational in Ukrainian.

drmpeg · 2 months ago

Here's my ATSC 3.0 transmitter in C++.

https://github.com/drmpeg/gr-atsc3

drmpeg commented on When a video codec wins an Emmy blog.mozilla.org/en/mozil... · Posted by u/todsacerdoti

drmpeg · 2 months ago

Here's the Emmy that C-Cube Microsystems won back in 1995 for the MPEG-2 (actually unconstrained MPEG-1) encoder chip set used in the roll-out of DirecTV.

https://www.w6rz.net/DCP_1235.JPG

The original DirecTV encoder was MPEG-1 at 704x480 using eight CL4000 chips. Then in 1995 when the MPEG-2 capable CL4010 was finished, the encoders were upgraded to MPEG-2 (frame only encoding). Then upgraded again to a 12 chip AFF (Adaptive Field/Frame) encoder when the firmware was completed.

https://www.w6rz.net/videorisc.png

drmpeg commented on Scientific and Technical Amateur Radio destevez.net/... · Posted by u/gballan

plugger · 2 months ago

I look forward to Escapade Blue and Gold returning, I plan to have a look at them with my X band setup. I'm running a 1.2m offset, which is significantly larger than the 60cm Daniel was using here.

drmpeg · 2 months ago

I believe he's using a 6m antenna at the Allen Telescope Array (ATA).