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RachelF

6,354 karma · joined February 9, 2012

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RachelF··on Turn your Android phone into a modern ham radio transceiver
The Qansheng's that I've tested have been fine, first harmonic down 44dB, which is OK for the FCC.

However, if you hack the firmware and transmit outside the bands the radio's RF is designed to transmit on, then you will probably see all sorts of spectral weirdness.

RachelF··on Turn your Android phone into a modern ham radio transceiver
Anything aviation-related normally has 5 to 10x cost of mass-market products.

Plus you probably need a licence to transmit in those bands.

RachelF··on Turn your Android phone into a modern ham radio transceiver
Yeah those "autopatch" devices were illegal - Ma Bell had rules against connecting any radio to the telephone system. Probably worried about long distance revenue.

The portable radios/cord free telephones back then were a bit of a legal gray-zone.

RachelF··on Cisco is abandoning the LoRaWAN space, and there's no lifeboat for IoT customers
Yes, it's deliberately a low bandwidth, cheap protocol. It's hard to make something with a big margin off it.

Still, it's bad for Cisco's reputation to abandon support for existing customers.

RachelF··on A Bendy RISC-V Processor
I agree, this CPU has double the transistors of a 6502, and runs at 1/20th of a 6502 speed. A silicon product will be faster, the size of a printed dot and use less power.

No word either on how many bending cycles the product supports.

Still, it's early days, and flexibility might have some use.

RachelF··on Rotation-Based Compression
Note that JPEGs can be rotated without decompression, just by swapping the axes of the compression cells.

Some of the software he uses may do this, others may decompress, rotate and recompress.

RachelF··on Google Cache is fully dead
Sadly, not knowing what used to be, erases history.

“The past was alterable. The past never had been altered. Oceania was at war with Eastasia. Oceania had always been at war with Eastasia.” ― George Orwell, 1984

RachelF··on In 1870, Lord Rayleigh used oil and water to calculate the size of molecules
Semi off topic:

Interesting to look at picture of the text of the 1890 paper. That typesetting is almost the same as modern scientific papers.

Maybe Rayleigh had an early copy of LaTeX? ;-)

RachelF··on Data sleuths who spotted research misconduct cleared of defamation
It's hard to generalize. The whole field of behavioural intelligence has lots of fake/unrepeatable studies.

Even Kahneman, who got a Economics Nobel has this issue:

https://retractionwatch.com/2017/02/20/placed-much-faith-und...

RachelF··on Data sleuths who spotted research misconduct cleared of defamation
The irony is that Francesca Gino and Dan Ariely are famous for their pop-sci/TED talks studying dishonesty. Turns out they were dishonest themselves.

https://www.npr.org/2023/07/27/1190568472/dan-ariely-frances...

RachelF··on Windows NT vs. Unix: A design comparison
The original NT was a great design, built by people who knew what they were doing and had done it before (for VMS). It was superior to the Unix design when it came out, benefiting from the knowledge of 15 years.

I worked on kernel drivers starting in with NT 3.5. However, over the years, the kernel has become bloated. The bloat is both in code and in architecture.

I guess this is inevitable as the original team has long gone, and it is now too large for anyone to understand the whole thing.

RachelF··on QUIC is not quick enough over fast internet
Also bear in mind that many of today's network cards have processors in them that handle much of the TCP/IP overhead.
RachelF··on How a 16th Century Explorer's Sailing Ship Works
If you like Hornblower, you should read the Aubrey Maturin series.

https://en.wikipedia.org/wiki/Aubrey%E2%80%93Maturin_series

RachelF··on LwIP – Lightweight IP Stack
Yes, it's impressive. I had to write one in assembly years ago. However, could only do UDP unfortunately as I didn't have enough memory for code and TCP buffers in 64kB.
RachelF··on State of S3 – Your Laptop is no Laptop anymore – a personal Rant
One wonders how many giga-watts of electricity Windows update consumes each year?
RachelF··on Microsoft's 'Recall' feature can't be uninstalled after all
It's more complex than that now. For the last 4 years, Microsoft has a "Medic Service" that will put Windows update back if you just move those files.
RachelF··on Starliner crew reports hearing "sonar like noises"
That capsule better keep quiet - Boeing doesn't like Whistleblowers ;-)
RachelF··on Australian employees now have the right to ignore work emails, calls after hours
For me, the interesting thing about Japanese work culture is that they pay white collar jobs overtime.

Paid overtime seems to be a blue-collar only thing in most English-speaking countries.

RachelF··on Designing my own watch (2020)
For a digital-only lightweight alternative that does everything a watch should do, the Casio F-E10 is ideal.
RachelF··on I've built my first successful side project, and I hate it
"- Invest in good docs..."

In my experience, end users don't read the docs or FAQ's or help search - they send you a question.

RachelF··on Intel Clear Linux: 16% more Ryzen 9 9950X performance
That's what comes with actually using the instruction set of modern CPU's instead of the lowest common denominator instruction set.

However, note that some of the modern instructions like AVX-512 use a lot of electrical power on the CPU, for example pushing a 12gen Intel chip above 300W.

RachelF··on Mike Mageek is dead
Very true. Their journalists understand the technology they are writing about and explain it clearly. They also provide background and a bigger picture. One can view them as sceptical, perhaps even jaded hacks, but what they write generally stands the test of time.

In my opinion, it is the best tech news website.

RachelF··on Games People Play with Cash Flow (2020)
The important axiom you forgot:

- The government needs to take your money via tax on profits.

Result: Via fancy accounting, businesses can pretend not to have profits and avoid tax.

RachelF··on National Instruments acquired by Emerson (2023)
NI used to be big and well known to the electronic engineers in the 1980's and 90's who helped develop the early Internet.

See ti.com - Texas Instruments

RachelF··on Google Pixel 9 Pro
Yeah, I have a Moto G84 12GB RAM for $180 - and it has features that these Pixels do not have:

- SD Card up to 1TB

- 3.5mm headphone jack

RachelF··on Windows 11 July Update Breaks Bitlocker, Forces Recovery
Microsoft don't seem to have a QA dept anymore.
RachelF··on The Phantoms Haunting History
Very true, there are other sources of the same ideas. It's even in the Bible: "You shall have no other gods before me", implying that El is the number 1 god.

Paul Johnson has gone out of fashion but his wide works have stood the test of time.

RachelF··on Firmware update hides a device’s Bluetooth fingerprint
Indeed. For most solid-state transmitters many of these non-linearities in envelope and frequency are temperature dependent too.

The same device will give different signatures at different temps.

RachelF··on Firmware update hides a device’s Bluetooth fingerprint
Google "umop ew" for a list.

UMOP stands for unintentional modulation on pulse. This will start you off with the foundation papers in the field.

RachelF··on Firmware update hides a device’s Bluetooth fingerprint
Thank you for that link.

There are many flaws in the paper's approach. There is much literature on this already, it has been investigated for decades. Much of the fingerprinting used comes from non-linearities in the RF power amplifiers, not the frequency.

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