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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

#121

Post by barrkel »

giantg2 wrote: post #15
james_pm wrote: post #13

Cordless phones were more "fun" to scan since it was generally your neighbours you heard just because of the range of those things. Also baby monitors were (and probably still are) wide open. Literally a 24/7 mic broadcasting for anyone to listen to. Pagers were also easy to listen to. You'd get short messages without context. A lot were office to doctor or dispatch to tradesperson.

Some baby monitors are using "encryption". I don't know if they are actually using encryption or just privacy codes. Even if they are using encryption, I doubt it's very secure stuff (probably 8 bit or something).

Our baby monitor uses DECT - it's basically a cordless telephone. While I wouldn't expect it to be encrypted to any significant degree, in most cases a baby monitor is either broadcasting silence with a little background room noise, or it's turned off. Once a monitor starts broadcasting noise, a parent intervenes.

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

#122

Post by HPsquared »

kabdib wrote: post #24
ed25519FUUU wrote: post #16

Earlier quoted context omitted.

Stories please!

I once overheard a phone interview for a position so interesting that I wanted to apply for it myself. The answer to "How did you hear about our company?" would not have gone well. :-)

"word of mouth"

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

#123

Post by tim-- »

jcrawfordor wrote: post #84
foepys wrote: post #81

Earlier quoted context omitted.

There are some smart home devices that use DECT Ultra Low Energy to communicate with their base station. It's a pretty cool tech because DECT uses its own frequency band and doesn't interfere with bluetooth or wifi in the often highly congested 2.4 and 5 GHz bands. Even firmware updates are possible because the bandwidth is large enough to push some megabytes through.

That's very cool. When I was a kid, a nearby department store (Fred Meyers on 39th and Hawthorne) used a large-scale DECT system for employee-to-employee and paging. Each staff member carried what was essentially a ruggedized cordless phone with an earpiece and they heavily used DECT's "intercom" handset-to-handset feature to talk to each other, and it was all on a PBX with their outside phone lines. I believe it was…

DECT VoIP base stations are still very much a thing.

http://www.grandstream.com/products/ip-voice-telephony/dect-...

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

#124

Post by firloop »

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).

Reminds me a lot of reading old GameFAQs guides

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

#125

Post by 2sk21 »

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…

I bought a RadioShack scanner in 1993. I found that even though 800-900 MHz was blanked out, reflections of cellphone signals were clearly audible! Back in the early 90s, sitting in my house, I was able to listen to cell phone conversions from cars on a highway near my house. You have to remember that early cell phones were so large that people mostly used them from cars.

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

#126

Post by ChrisMarshallNY »

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…

I used to work for a company that made “super Bearcat scanners.” These were “DC-to-light” scanners, with multiple demodulation methods (SSB, DSB, Phase, Frequency, Amplitude, etc.). They cost about 40 grand each, in the early 1980s.

Needless to say, most customers were military or TLAs.

We could listen in on mobile phone conversations without much difficulty.

Then frequency-hopping started to become en vogue, along with encryption, and made it a lot more difficult to eavesdrop. Most of that happened after I left the company.

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

#127

Post by polote »

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?

> apologize for the design of my blog being almost actively hostile to users

I edit a newsletter of blogs of HN and I can tell you that your design is not more hostile than most HN bloggers, don't worry you are fine

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

#128

Post by jacquesm »

FiddlerClamp wrote: post #38
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…

The funniest thing was that people were convinced that you could cut more diodes (if only you knew which ones) and enable more hidden frequencies. They couldn't understand that this was a one-shot deal. I imagine there were quite a few that ended up destroying their scanners trying.

At 15 cents per diode I don't think that would be a particularly expensive fix or worth throwing out an otherwise perfectly good scanner for.

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

#129

Post by DanBC »

quercusa wrote: post #11
augstein wrote: post #4

This blogpost is unfortunately barely readable on a small screen, because of the fixed line widths.

He's faithfully captured the 1980s BBS vibe.

Here's what I get. 1980s BBSs didn't have wrapping this bad unless you were quoting.

  To start: yes, long time no see. Well, COVID-19 has been like
  that. Some days I
  feel accomplished if I successfully check my email. I finally
  managed to clear
  out a backlog of an entire handfull of things that needed
  thoughtful responses,
  though, and so here I am, screaming into the void instead of at
  anyone in
  particular.
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