drmpeg

6 ms·

31.
by drmpeg 11mo ago
It's theoretically possible. 63.1 dbW = 93.1 dBm (240 watts + 39.3 dB gain) path loss at 5760 MHz = 283.2 dB (at perigee) RX gain = 39.3 dB 93.1 - 283.2 + 39.3 = -150.8 dBm Noise floor at 1.2 dB noise figure and 500 Hz bandwidth = -151
32.
Analysis of Hedy Lamarr's Contribution to Spread-Spectrum Communication(researchers.one)
66 points by drmpeg 11mo ago|54 comments
33.
by drmpeg 11mo ago
When I worked at LSI Logic in the 2000's, there were a lot of young Europeans (mostly Italian) on the staff. They had rented a house in Palo Alto which was affectionately called "The Pleasure Lounge". It was just one of those
34.
by drmpeg 11mo ago
I got to go inside Cheyenne Mountain Complex back in 1988 when I was the project engineer for the DSP satellite ground network upgrade. Unfortunately, I didn't get to see any control room. In fact, I didn't get to see much at all.
35.
by drmpeg 1y ago
Here's a video of AM modulation. SDR transmitter (running GNU Radio) connected to an SDR receiver. https://www.youtube.com/watch?v=9LsJn0CyyZI
36.
by drmpeg 1y ago
Cool. We had a small company in San Diego called Metacomp (long gone now) design a Z8530 add on module for their 80186 based Multibus board. It had two Z8530 chips on it and you could have two modules on the base board. So 8 channels total
37.
by drmpeg 1y ago
Multi-link HDLC. That brings me back to 1985 and the Intel 8274, Zilog Z8530 and the Western Digital WD2511 (that implemented the layer 2 protocol in silicon).
38.
ATSC 3.0 Further Notice of Proposed Rulemaking [pdf](docs.fcc.gov)
1 points by drmpeg 1y ago|0 comments
39.
by drmpeg 1y ago
Same experience here with hospital pagers. I tried this way back in 2013 when I first started with SDR. Even without covid, the messages were hideous and depressing. Not recommended.
40.
by drmpeg 1y ago
Here's some "glitch art" made with an SDR transmitter output power set to exactly the SNR threshold of the receiver. https://www.w6rz.net/pixellation.mp4
41.
by drmpeg 1y ago
It's going from the frequency domain (parallel symbol streams) to the time domain (multi-carrier RF), so it's using the inverse FFT.
42.
by drmpeg 1y ago
I've never bothered listening to music while coding. If I'm in the zone, it's entirely extraneous and I don't even hear it. At my first job in Silicon Valley, I used to code right on the production floor totally obliviou
43.
by drmpeg 1y ago
This is pretty pedantic, but allocated radio frequencies start at 8.3 kHz. https://www.fcc.gov/sites/default/files/fcctable.pdf
44.
by drmpeg 1y ago
Yes, this is what makes moon bounce (EME) attainable. The gain of the moon is about 142 dB at 1296 MHz.
45.
by drmpeg 1y ago
Here's what 4096 carriers looks like. https://www.youtube.com/watch?v=saac0ZtTeX4 https://github.com/drmpeg/gr-paint
46.
by drmpeg 1y ago
$30,000 SDR wasn't good enough. Zoinks!
47.
by drmpeg 1y ago
It's an organized event, just like Field Day. The most popular one is in June, since sporadic-E propagation on 50 MHz is available. https://www.arrl.org/june-vhf To be honest, I've pretty much phased out on conven
48.
by drmpeg 1y ago
I used the equipment for the same reason, to communicate through the Oscar 10 and 13 satellites at home. Oscar 10 was launched in 1983. At that time, I was living in an apartment. I strung up some smaller yagis on the balcony that fortunate
49.
by drmpeg 1y ago
It's certainly a contest for some groups, but I can't say what percentage that would be. There's many many groups that aren't even remotely competitive and for some groups it's primarily a social event. When we part
50.
by drmpeg 1y ago
I had the equipment. 2-meter SSB/CW receiver, 70cm SSB/CW transmitter, large 2-meter and 70cm yagi antennas and an azimuth/elevation rotator. Oscar 10 and 13 were amateur satellites in HEO (Molniya) orbit. They were super fun
51.
by drmpeg 1y ago
Back in the early 90's, I worked with some guys that were in the San Jose State radio club, W6YL. Although Field Day is not a contest, these guys really really wanted to finish in the top 10 for class 2A. They found out that I had an O
52.
by drmpeg 1y ago
It should be noted that TVFool hasn't been updated since 2017. It will give incorrect results for stations that changed frequency after the 600 MHz auction in 2016-2017. Use RabbitEars instead. https://www.rabbitears.info&#x
53.
by drmpeg 1y ago
It's a ham radio contest station. Doesn't really have to do with SDR. https://www.youtube.com/watch?v=Dd4NWyFq-dM
54.
by drmpeg 1y ago
There's the similar DragonOS for the Raspberry Pi. https://sourceforge.net/projects/dragonos-pi64/
55.
by drmpeg 1y ago
When C-Cube Microsystems was bought by LSI Logic in 2001, they grandfathered the old C-Cube e-mail policy of first/last initial. I ended up with the sweet e-mail address, re@lsil.com. Pretty good for a fairly large company. When Abhi T
56.
by drmpeg 1y ago
The specific allocation is 1400 to 1427 MHz. It is reserved for radio astronomy (the hydrogen line is at 1420.4 MHz), passive (receive only) Earth exploration satellites and passive space research. In the US, 1240 to 1400 MHz is allocated t
57.
by drmpeg 1y ago
https://github.com/OFFTKP/felix86/
58.
by drmpeg 1y ago
Who remembers when route 237 was country road with a flashing signal at Maude Avenue? The Bier Garten (not sure of the spelling) on the corner was a favorite lunch hangout with awesome cheeseburgers.
59.
by drmpeg 1y ago
I started with GNU Radio back in 2013, and have had a lot of fun with it. My "magnum opus" is an ATSC 3.0 transmitter. https://github.com/drmpeg/gr-atsc3 Demo clip running on a HiFive P550 RISC-V platform. h
60.
by drmpeg 2y ago
I can't remember now, but I want to say less than 5 dollars. I do remember that one of my customers with a fairly large lawn paid 2 dollars an hour , which I was very happy with.

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