Radio/Scanner Advice

[SkyvanDelta]

Re: Radio/Scanner Advice

1. Decades ago, I use to listen to a Police Dept on the scanner because there was a lot of criminal activity that was interesting to listen to. Eventually, due to the criminals listening to the channels, I believe they scrambled it and made it impossible for the average person to listen. Does that sound possible?

2. Isn't the technology available to make it impossible for the average person to follow radio transmissions? The Secret Service, FBI, Air Force One, Military...are able to scramble their radios, correct?

[Tibia]

Re: Radio/Scanner Advice

Chris...

[Sky Critter]

Re: Radio/Scanner Advice

1. Decades ago, I use to listen to a Police Dept on the scanner because there was a lot of criminal activity that was interesting to listen to. Eventually, due to the criminals listening to the channels, I believe they scrambled it and made it impossible for the average person to listen. Does that sound possible?

2. Isn't the technology available to make it impossible for the average person to follow radio transmissions? The Secret Service, FBI, Air Force One, Military...are able to scramble their radios, correct?

See item 3 above. The technology exists, the equipment does not (in the general aviation market).

[Tibia]

Re: Radio/Scanner Advice

Chris,

Yagi beams work but suffer when hunting short duration interference due to the time required for recognition and triangulation. We now use mobile ground plane antenna arrays with either doppler shift sensing electronics or time of arrival sensing electronics. With gps input, we end up with a heading to the offending station. Requires a little more time to location when in high density urban areas but overall, it works very well.

Bob

[AirDOGGe]

Re: Radio/Scanner Advice

So if it's possible to transmit, why doesn't the Air Races have their own frequencies that are issued to certain people only?

And where would these frequencies come from? The air wave bands are entirely filled and regulated, and there are no more available frequencies anywhere that one could claim as their own for such a use.

The frequencies are all taken and reserved for certain uses, and considering the massive costs of licensing a block of frequencies corporations have to pay to run their wireless network or broadcast systems, I doubt any would be willing to give up space.

Additionally, If any frequency was assigned to the races as you suggest, it would certainly have to fall within the aviation band of 108-136 mhz, to avoid possible interference with other radio airwave users. I sincerely doubt tranceiver makers would want to put filters in their products to block any portion of the aviation spectrum.



Finally, a generic answer to the generic question, "If the tech exists, then why doesn't a device using said tech exist?"

The generic answer: Money. We can have moving sidewalks and roads that guide cars themselves and vacation resorts on the Moon all kinds of other wonders conceived by imaginative folk and engineers...but who's gonna pay for it?

[AirDOGGe]

Re: Radio/Scanner Advice

1. Decades ago, I use to listen to a Police Dept on the scanner because there was a lot of criminal activity that was interesting to listen to. Eventually, due to the criminals listening to the channels, I believe they scrambled it and made it impossible for the average person to listen. Does that sound possible?

2. Isn't the technology available to make it impossible for the average person to follow radio transmissions? The Secret Service, FBI, Air Force One, Military...are able to scramble their radios, correct?

1. Services like police and emergency switched to trunked radio systems in the 1990s or earlier.

""Trunked" radio systems differ from "conventional" radio systems in that a conventional radio system uses a dedicated channel (frequency) for each individual group of users, while "trunking" radio systems use a pool of channels which are available for a great many different groups of users.

For example, if police communications are configured in such a way that twelve conventional channels are required to permit citywide dispatch based upon geographical patrol areas, during periods of slow dispatch activity much of that channel capacity is idle. In a trunked system, the police units in a given geographical area are not assigned a dedicated channel, but instead are members of a talk-group entitled to draw upon the common resources of a smaller pool "


2. Not all government or military frequencies get scrambled or anything of that nature (not everything is top secret ), and yes, the technology is there to monitor them, but by law it's illegal to make radios for consumer use that pick up restricted government-use bands.

You can most of what you need to know about radio frequency assignments here: http://en.wikipedia.org/wiki/Radio_spectrum

[Sky Critter]

Re: Radio/Scanner Advice

The reason you don't hear much police chatter anymore is because most police and sheriff departments use a MDC (mobile data communicator). Its a secure digital wireless network that's somewhat like texting.

[AirDOGGe]

Re: Radio/Scanner Advice

The reason you don't hear much police chatter anymore is because most police and sheriff departments use a MDC (mobile data communicator). Its a secure digital wireless network that's somewhat like texting.

So technology has moved beyond trunked systems. I should have realized with wireless phones being so common now, and digital instead of analog to boot.

I haven't had a scanner since 1999. I need to catch up....again. Thx Sky Critter.


.

[Sky Critter]

Re: Radio/Scanner Advice

So technology has moved beyond trunked systems. I should have realized with wireless phones being so common now, and digital instead of analog to boot.

I haven't had a scanner since 1999. I need to catch up....again. Thx Sky Critter.


.

Funny but not, cops are driving and texting in a sense.

[AirDOGGe]

Re: Radio/Scanner Advice

Funny but not, cops are driving and texting in a sense.

They also get to carry guns. I'M not gonna argue with 'em.

[lowpasskid]

Re: Radio/Scanner Advice

I'm no expert on scanners or radio system's but I am a student. MCD system's are analog, regular systems, PTT like NEXTEL phone's were/are. Bay Area/ALCO PD are trunked systems. i listen wheni go there on a Uniden BC396. out here in the central valley,Tracy PD and the sherriffs are now digital.now i need to get a new scanner to listen to the law out here, about $500 to start with. have to wait untill after Reno though.
Radio reference..com has everything you need to know about scanning.
check it out,
The Low Pass Kid...

[Sky Critter]

Re: Radio/Scanner Advice

This is just one of the MDC system providers on the market. These systems do not replace VHF comm systems but, rather enhance capabilities. Officers can type in license plate numbers for check and get all the primary info back via text. It also allows silent communication during some operations where they know voice comms could compromise the mission.

http://www.crimestar.com/mdc_main.html