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Why radio receivers won’t tune 800-900 MHz

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Re: Why radio receivers won’t tune 800-900 MHz

#41

Post by lostlogin »

saurik wrote: post #30
jcrawfordor wrote: post #27

Hi all, I am the author. I 1) have no idea how this made it to the top position, 2) now feel much guiltier about posting so infrequently, 3) apologize for the design of my blog being almost actively hostile to users, but then maybe that was the point?

Re 3: if it makes you feel any better--or worse! (most of the time I make people feel worse...)--I have added your blog to my list of "websites whose design I really like" ;P (the only thing I disagree with strongly is the seemingly-fixed word-wrapping, as it causes random-feeling new-lines while reading on my iPhone X screen).

I thought those were typos, accidental line breaks.

Re: Why radio receivers won’t tune 800-900 MHz

#42

Post by jcrawfordor »

breput wrote: post #10

I had (and probably still have) a Radio Shack Pro-2006 scanner from the late 80's. Even pre-Internet, instructions on how to bypass the cellular band block were easily found on Fidonet and local BBSes, and all it involved was removing a single diode. https://www.wentztech.com/radio/Equipment/Pro2006/pro2006mod... It was really a golden time for snoop...er..listening to cellular phones because they were so enormously…

Cordless phones are a whole different and rather interesting topic. The huge security issues with early cordless phones lead to DECT (or technically DECT 5.0) becoming widespread in the US, and it's actually a rather interesting protocol with a very complex and rich set of capabilities considering we normally only see it used for simple cordless phones. IP over DECT is an uncommon but interesting application.

Re: Why radio receivers won’t tune 800-900 MHz

#43

Post by jcrawfordor »

Sebb767 wrote: post #32

Seems we hugged the site to death :( Here's an archived version: https://web.archive.org/web/20201213003741/https://computer.... EDIT: Seems to be back up.

oops. everything seems fine on my end, but my whole Enterprise Hybrid Cloud is a single pizzabox in a low-rent datacenter that I "fully manage" by running updates when I remember to. I put it on CloudFlare just to be safe and make sure my packets are adequately mixed with pharma spam for transit.

Re: Why radio receivers won’t tune 800-900 MHz

#44

Post by wiml »

lsllc wrote: post #19

Anyone have any recommendations on a "modern" digital trunking scanner? (handheld) I have an old GRE PSR-500 which isn't terrible, but I'm looking to replace it as it has next to zero software support for programming it and doing it by hand is a real pain. You'd think in this day and age someone would make a scanner with a companion app connected to Radio Reference for programming. Would be nice to have bluetooth aud…

Since we're on HN, how about an RTLSDR, a Pi, and op25?

Re: Why radio receivers won’t tune 800-900 MHz

#45

Post by jcrawfordor »

lsllc wrote: post #19

Anyone have any recommendations on a "modern" digital trunking scanner? (handheld) I have an old GRE PSR-500 which isn't terrible, but I'm looking to replace it as it has next to zero software support for programming it and doing it by hand is a real pain. You'd think in this day and age someone would make a scanner with a companion app connected to Radio Reference for programming. Would be nice to have bluetooth aud…

I think much of the scanning crowd has either 1) abandoned interest in digital trunking systems or 2) switched to SDRs, which is an unfortunate state of affairs as the state-of-the-art in SDR trunking decoders is actually pretty bad.

Re: Why radio receivers won’t tune 800-900 MHz

#46

Post by KMag »

LeoPanthera wrote: post #7
LMYahooTFY wrote: post #6

Earlier quoted context omitted.

I take it that was related to the munitions classification for encryption?

Yep. https://en.wikipedia.org/wiki/56-bit_encryption

All of the SSL 3.0 / TLS 1.0 EXPORT cipher suites are actually limited to https://en.wikipedia.org/wiki/40-bit_encryption , see for instance page 60 of https://www.ietf.org/rfc/rfc2246.txt

For a while, exports were limited to 40-bit symmetric key strength and 512-bit moduli for DH and RSA. I had forgotten about the limits being raised to 56 bits for a few years before being fully dropped by the Clinton administration.

There was a brief attempt to get around the pushback against key length restrictions with the Clipper chip[0]. The idea was to give everyone 80-bit Skipjack encryption while enabling U.S. law enforcement intercept by having the chip refuse to function if it wasn't shown a valid escrow message (LEAF) for the key it was using. Skipjack was classified at the time and supposedly stronger than anything commercially available at the time. The problem was that LEAF itself only used a 16-bit authentication code, so it was trivial to bruit-force another LEAF message that would work with your session key, but yield garbage data in a wire tap.

[0] https://en.wikipedia.org/wiki/Clipper_chip#Technical_vulnera...

Re: Why radio receivers won’t tune 800-900 MHz

#49

Post by jcrawfordor »

rsync wrote: post #39
jcrawfordor wrote: post #27

Hi all, I am the author. I 1) have no idea how this made it to the top position, 2) now feel much guiltier about posting so infrequently, 3) apologize for the design of my blog being almost actively hostile to users, but then maybe that was the point?

Why do I recognize your name ? There's some hazy link here between "JB Crawford" and Kuro5hin and ... ? Or is that just a coincidence / faulty link in my memory ?

I think I did use Kuro5hin for a time, but if you have seen my writing elsewhere it is most likely LWN or some miscellaneous technical training vendors, both of which I contributed to for a while before my life got a little crazy. I'm actually currently getting back into freelance writing, so while I have fifteen minutes of fame... my first passion before technology was writing and teaching, and I write and develop training on technical topics I am interested in (there's a number of them). Contact info in my profile.
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