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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

#51

Post by jcrawfordor »

lostlogin wrote: post #41
saurik wrote: post #30

Earlier quoted context omitted.

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.

Yes, the script that generates the website was written in one evening when I was not entirely sober, and it has some weird behavior around linebreaks that I triggered by typo. Somewhere on my todo list is to add markdown parsing so I can do cutting-edge things like indented block quotes while still having the text reflowable for the RSS feed, but then I'll have to decide how to represent headings and links while still keeping to my 80x24 video terminal aesthetic.

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

#52

Post by jcims »

jcrawfordor wrote: post #45
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.

I went hogwild with this at the beginning of the RTLSDR era of SDR. I just started picking it back up after getting some better hardware and was kind of bummed at how little the quality of the voice decoding has progressed despite what appears to be a ton of energy invested.

If I recall correctly some of it is licensed and/or patented and people are just having to reverse engineer the protocols. I’d pay for a commercial demodulator to snap in.

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

#53

Post by supertrope »

heavyset_go wrote: post #20
breput wrote: post #14

Earlier quoted context omitted.

As a person who also did this, I feel like it has encouraged my suspicion of communication privacy. All it takes is listening to your married neighbor talking to their boyfriend/girlfriend to realize that someone could be doing it to you. The difference now is that it doesn't have to be within a 150 foot radius.

Now, not only does someone not need to be actively listening, they don't even need to save the audio. Just convert it to text, keep it indexed and whatever three letter agency is doing the tapping has an easily searchable record of your communications should they ever feel the need to look into you without you knowing.

Recording all calls is well within the financial and material means of the US Government. http://blog.archive.org/2013/06/15/cost-to-store-all-us-phon...

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

#55

Post by throwaway611657 »

myself248 wrote: post #48
ashleyn wrote: post #23

The article mentions the Oki 900. Here's a Wired article mentioning how hackable it really was: https://archive.is/AEq0B

MENU SND END RCL STO CLR

"GOOD TIMING!"

My friends and I used to get piles of old Okis at First Saturday in Dallas. We'd leave Austin at midnight and drive 3 hours to get all the pre-dawn good deals. I remember we got a hold of some mobile data terminals and tranceivers too, though we never quite got around to the mischief we dreamed of using them for. POCSAG decoding was another good time. Ah, to be young again!

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

#56

Post by temporallobe »

jcrawfordor wrote: post #51
lostlogin wrote: post #41

Earlier quoted context omitted.

I thought those were typos, accidental line breaks.

Yes, the script that generates the website was written in one evening when I was not entirely sober, and it has some weird behavior around linebreaks that I triggered by typo. Somewhere on my todo list is to add markdown parsing so I can do cutting-edge things like indented block quotes while still having the text reflowable for the RSS feed, but then I'll have to decide how to represent headings and links while stil…

If you don’t mind the conversion happening on the front-end side, Showdown.js has worked really well for me on a few projects.

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

#57

Post by fortran77 »

jcrawfordor wrote: post #45
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.

You'd be wrong if you think that. We're all using Uniden SD200

See: https://www.bearcatwarehouse.com/Trunking

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

#58

Post by molticrystal »

As a child in the 80s I was given an intellivision and a old (even in those years) ~13" black & white tv to play it on.

It had the ability to tune to the higher UHF channels 70-83 [0] which while planned for use in tv broadcast, never ended up being used, but they didn't know that at the time of the construction of the tv set. The frequency covered by those channels were reallocated in 1982 by the CCIR worldwide convention, and covered approximately 806 to 890mhz.

What was most interesting to me as a young teenager in the early 90s about this particular tv set, was that I found out I could hear an occasional phone call when tuned to those UHF channels, even more so when I used the fine tuning nob.

On a side note, the tv set also allowed me to view scrambled channels on the cable system which I could unscramble to various degrees by turning the tuning nob at certain rates back and forth. I suppose modern 90s systems were not designed with my old tv set in mind.

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

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

#59

Post by refurb »

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…

Related to that, I can remember borrowing a friend Motorola cell phone in the early 90's, probably the 9800 model, still unencrypted analogue transmission.

Anyways, you could enter the service menu and select which tower frequency you'd like to receive or send on. I remember playing with it and selecting the same channel to send/receive and there was already an on-going call. I heard one of the people say "did you hear that?" and I pulled the battery, it freaked me out.

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

#60

Post by bmcahren »

I'll never forget using grandpa's police scanner trying to find interesting sounds and tuned to one of the ~1800 frequencies and shockingly discovering that the cordless phone we bought in ~2003 was completely unencrypted broadcasting in the clear at half of the frequency I was listening to. My mom was in disbelief and we bought a new phone with DECT shortly after. I was a bit shocked myself.
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