Why aren't scanners continuous?

[zz0468]

I'll admit it has been many years since I actually read the ECPA, so I may be way off on this, but... didn't it merely say that they couldn't manufacture radios capable of monitoring cellular communications, rather than spelling out in black and white which exact frequencies those were? In other words, does the ECPA actually address those now-dead frequencies, or does it only address the communications that were on them at the time? If it is the latter, then there is no legal revision necessary for the manufacturers to resume putting those freqs into the scanners again.

Those frequencies are NOT dead. Not by any stretch of the imagination. There's simply nothing there that you're allowed to listen to. It's illegal, it's digital, it's encrypted. For the few analog systems still on mentioned by n2mdk, that falls under the illegal category. Bottom line is, there is no reason for the scanner manufacturers to consider marketing scanners that cover that range. They already cover everything that's there to be covered. No, really... they do.

 

[kd7rto]

I disagree with the premise that I cannot learn anything useful from a signal which I cannot demodulate.

Suddenly getting close call hits on an FBI frequency is an interesting thing to note, even if they can’t be turned into an audible voice.

If I had an 800 MHz cell site within a block of my QTH, I certainly would want to periodically sweep that range with a spectrum analyzer to ensure it is not causing any interference problems with any of the radios I use in my hobby.

Furthermore, if it could be determined through sigint which cellular carrier’s total subscribers and minutes of use are on the increase, and which carriers are on the decrease, the average joe might not care, but there are people who would.

 

[w0fg]

Read it again:

FCC rule 15.121 (Code of Federal Regulations, title 47, chapter I, part 15, section 15.121) says, in relevant part:

(a) scanning receivers shall:
(1) Be incapable of operating (tuning), or readily being altered by the user to operate, within the frequency bands allocated to the Cellular Radiotelephone Service in part 22 of this chapter (cellular telephone bands). ... Scanning receivers, and frequency converters designed for use with scanning receivers, also shall be incapable of converting digital cellular communication transmissions to analog voice audio.

(b) Except as provided in paragraph (c) of this section, scanning receivers shall reject any signals from the Cellular Radiotelephone Service frequency bands that are 38 dB or lower based upon a 12 dB SINAD measurement, which is considered the threshold where a signal can be clearly discerned from any interference that may be present.

Both tuning to the frequencies and converting digital transmissions seem to be prohibited by current law.

 

[Don_Burke]

I disagree with the premise that I cannot learn anything useful from a signal which I cannot demodulate.

Suddenly getting close call hits on an FBI frequency is an interesting thing to note, even if they can’t be turned into an audible voice.

If I had an 800 MHz cell site within a block of my QTH, I certainly would want to periodically sweep that range with a spectrum analyzer to ensure it is not causing any interference problems with any of the radios I use in my hobby.

Furthermore, if it could be determined through sigint which cellular carrier’s total subscribers and minutes of use are on the increase, and which carriers are on the decrease, the average joe might not care, but there are people who would.

I agree with all of this.

If the last two things were important to me, I would figure out a way to do them with something that did not meet the CFR definition of a "scanning receiver."

 

[zz0468]

I agree with all of this.

If the last two things were important to me, I would figure out a way to do them with something that did not meet the CFR definition of a "scanning receiver."

A spectrum analyzer...

 

[stevewebb3275]

I want to Buy a PRE fcc ban scanner, Where can i buy one?????

i used to have a uniden bct7 that could pick up cell phone calls and i loved it, then i heard the fcc stopped the manufactuers to from making them, so does anyone Know where i can buy one before the bann came in?? thanks

 

[W4KRR]

i used to have a uniden bct7 that could pick up cell phone calls and i loved it, then i heard the fcc stopped the manufactuers to from making them, so does anyone Know where i can buy one before the bann came in?? thanks

You might try looking on eBay. But there isn't much point; there are very few analog cell phones left in use these days.

 

[jon_k]

i used to have a uniden bct7 that could pick up cell phone calls and i loved it, then i heard the fcc stopped the manufactuers to from making them, so does anyone Know where i can buy one before the bann came in?? thanks

All cellular is digital now. I doubt anyone is using those brick phones for cellular anymore. You'd just hear digital noise now days.

 

[poltergeisty]

edit delete please

 

[n1das]

I disagree with the premise that I cannot learn anything useful from a signal which I cannot demodulate.

Suddenly getting close call hits on an FBI frequency is an interesting thing to note, even if they can’t be turned into an audible voice.

Agreed!

If I had an 800 MHz cell site within a block of my QTH, I certainly would want to periodically sweep that range with a spectrum analyzer to ensure it is not causing any interference problems with any of the radios I use in my hobby.

Agreed!

Supposedly there is a clause in ECPA'86 that says it's legal to monitor for interference to the extent necessary to identify the source of the interference. I know that's a vague description but the clause in ECPA'86 is just as vaguely worded.

 

[PhilJSmith67]

Now, to be fair, it IS possible to make a 0-1300 MHz receiver that won't let the elephants and monkeys in, but it not only wouldn't be cheap, it probably wouldn't be even remotely affordable. Everyones favorite uncle has such toys, and if you could afford the $20,000 price class, maybe you could too. I've often thought about what it would take to build something...

An $80 transistor on the front end with a +45 ip3 and .5 db nf, high side injection with a 3 GHz first IF for image suppression, YIG local oscillator phase locked to a low noise synthesizer... Hmmm...

This could be done with ebay parts for under $1000. But there's still nothing to listen to on most of that spectrum. It's an interesting technical problem, but little more.

Excellent point.

Segments of spectrum have to be tuned (or block-converted) in ranges in order for reception to be effective. Adding 216-406 on a scanner typically requires another conversion circuit. Same goes for other ranges typically omitted, such as 54-108, 512-806, 960-1240, frequencies below 25, etc. That costs money. There's a lot more going on with reception of radio frequencies than just a display, cpu and buttons.

It's kind of like a car... "If they can make a car with a speedometer that goes to 120, why don't they just make a car that goes 400?" Think about what goes under the hood.

Of course, the cell-band blocks are purely done in the CPU. I can guarantee you that every 800MHz-capable scanner made has all the RF hardware needed to tune continuously from 806 to 902 MHz or beyond, but 824-849 and 869-894 MHz are prohibited by the cpu/firmware, in such a way that removing the blocks is virtually impossible.

 

[PhilJSmith67]

All cellular is digital now. I doubt anyone is using those brick phones for cellular anymore. You'd just hear digital noise now days.

Most of the country, yes... But not entirely.

Illinois Valley Cellular (IVC), which lies about 60+ miles south of Chicago and covers a large area, has not yet terminated analog service. At my house 35 miles south of Chicago, I am looking at the phone right now (switched to analog-only), and it's registering signal from System ID 1178, which is the IVC system.

I'm using a Nokia i3589. It's not new by any means, but it does have 1xRTT digital, text messaging, mobile web, color screen, and it's definitely not a "brick."

On the topic of not bothering with listening to digital signals (or digital "noise")... I hear all sorts of digital signals on my scanners and shortwave receivers, and just by the sound can identify nearly all of them. The sound of an AMPS data channel is highly unique. So are the digital signals of POCSAG, EDACS, ATCRBS, RDS/RBDS, ProVoice, RTTY, EAS, GPS, APCO25, CDMA, IBOC, X-10, GSM, LORAN-C, and on and on. I suggest to anyone serious about getting into the world of RF today to take a step back and listen to the analog rendition of various digital signals. It is a worthwhile learning experience, and can be invaluable for troubleshooting digital equipment, especially when it involves resolving interference. Keep in mind that EVERY signal propagates in an analog world. It's the circuits we build that interpret these signals digitally.

So... Having said that, I prefer receivers with as few frequency coverage gaps as possible (one reason why I still have an old Regency MX-7000 in my arsenal, and recently bought a BR330T). I mostly listen to analog signals of course, but I want to hear what these various digital signals sound like, too.

 

[BillQuinn]

There is ONE Scanner

There is 1 scanner that can receive on any frequency between 30 mhz and 2400 mhz, or something like that. But it is only available to government agencies! Obviously!!

 

[BillQuinn]

I think i saw it on HRO's website.

 

[W4KRR]

There is 1 scanner that can receive on any frequency between 30 mhz and 2400 mhz, or something like that. But it is only available to government agencies! Obviously!!

Well, my Icom R20 will receive from 150 khz to 3300 MHz continuous, no gaps, and I am not a government agency! :lol:

 

[zz0468]

Well, my Icom R20 will receive from 150 khz to 3300 MHz continuous, no gaps, and I am not a government agency! :lol:

If you hear anything of interest above 1300 MHz, be sure and let us know. In fact, if you hear anything at all, tell us.

 

[W4KRR]

If you hear anything of interest above 1300 MHz, be sure and let us know. In fact, if you hear anything at all, tell us.

I've never heard anything above about 940 MHz. But I was responding to BillQuinn, who seemed to imply that wide band, continuous coverage scanners were only available to the government, which, of course, isn't the case.

 

[RogerH11]

I've never heard anything above about 940 MHz. But I was responding to BillQuinn, who seemed to imply that wide band, continuous coverage scanners were only available to the government, which, of course, isn't the case.

Legally that is. They pass a dumb law, my money left the country. Now with it all digital HERE, I shop at home again.