BCD436HP/BCD536HP: Does Close Call work with P25?
- Thread starter tamar
- Start date
Yes, it does work for strong signals. It will alert whenever you are close to a radio that's transmitting, which is handy for finding out car to car frequencies that are not part of the trunking system. Also, you will be able to find the input frequencies used on the system.
Do you know what range it can be? Can it detect one mile away or is it just if its close?
It is simply (strong) signal strength, so the answer is - it depends...
ERP of the TX antenna, line of sight, your antenna's gain, etc, etc, etc....
And it can't close call an encrypted P25 signal? Not to listen, just to know that the signal is near.
I've been under the impression that CloseCall did not work on P25. This is interesting news.
Did the older radios, like the BCD396XT or BCD996XT, also capture P25 signals with CC? I ask this because I had asked Paul Opitz at a get together years ago if it worked on digital signals and he told me no. This was back around the time the 396/996 was out.
I'm glad to hear that it does work on P25 signals however. I've been thinking it only works on analog for a long time now.
Brian
COMMSCAN
Did the older radios, like the BCD396XT or BCD996XT, also capture P25 signals with CC? I ask this because I had asked Paul Opitz at a get together years ago if it worked on digital signals and he told me no. This was back around the time the 396/996 was out.
I'm glad to hear that it does work on P25 signals however. I've been thinking it only works on analog for a long time now.
Brian
COMMSCAN
On a typical system, P25 or not, a handheld radio has to be within a block or so of your location. Even in-vehicle radios anymore are really just docks for a handheld.
So, depending on how busy cars/trucks/public safety folks are within your neighborhood, you may never get a hit on Close Call.
Can it close call the P25 handheld radio? A block or a mile would be good, an alternative to radar detection for police
A block or two, yes it works if he/she is transmitting. But officer will already have you locked in on radar at those distances, so it is not an alternative to a radar detector.
If it would be at least half a mile it would work, I tried a radio frequency detector and it worked on police but most of them are P25 and probably encrypted, how can I close call and detect that? Encrypted can't listen but can still be detected, but not sure which scanner can close call a P25 handheld radio
AB5ID
Member
Not a radar detector but a radio detector. Heard about these in the UK , article says US band versions on the way.
www.foxnews.com
'Police detector' monitors emergency radio transmissions | Fox News
'Police detector' monitors emergency radio transmissions
www.foxnews.com
Ubbe
Member
CloseCall are a frequency counter and as such it needs a clean signal to be seen above everything else in the spectrum. In a city environment you can expect a lot of signals in the air that could make the range go down to 100ft.
For the "Police Detector" Target Blue-Eye it is a receiver tuned to the Tetra 380-385MHz band that detects RF pulses, and as the GPS positions always are sent as minimum of two pulses it will be something like a 50mS distance between them that can be used as a window where two pulses must be seen, as something like a 17Hz modulation, to trigger an alert.
You can use a SDR dongle and a RaspberryPie computer to detect any RF signals within that RF spectrum that works to detect nearby Tetra mobiles and if you add a 17Hz detector function it will filter out any stray signals. Then add a RF bandpass filter and you have a Target Blu-Eye. But from the pictures of its inside I believe the Blue-Eye to be built around a conventional receiver as a SDR one does not perform as good RF wise.
In my country they partly finance the public safety system be renting out capacity to commuter transports, daycare, elderly care at home, electrical companies, road works and so on. It makes it detect a lot of non public safety transmissions. In a couple of years our public safety will move to a LTE 700MHz system. Then it will probably be possible to detect any RF in that specific frequency band, and it probably will be pulsating at a specific rate.
One issue with Tetra, and probably other systems as well, are that mobiles reduce their transmit power when they are close to a tower and can go down to 10mW which makes it difficult to receive and detect until you are a few feet from the one that transmits.
/Ubbe
For the "Police Detector" Target Blue-Eye it is a receiver tuned to the Tetra 380-385MHz band that detects RF pulses, and as the GPS positions always are sent as minimum of two pulses it will be something like a 50mS distance between them that can be used as a window where two pulses must be seen, as something like a 17Hz modulation, to trigger an alert.
You can use a SDR dongle and a RaspberryPie computer to detect any RF signals within that RF spectrum that works to detect nearby Tetra mobiles and if you add a 17Hz detector function it will filter out any stray signals. Then add a RF bandpass filter and you have a Target Blu-Eye. But from the pictures of its inside I believe the Blue-Eye to be built around a conventional receiver as a SDR one does not perform as good RF wise.
In my country they partly finance the public safety system be renting out capacity to commuter transports, daycare, elderly care at home, electrical companies, road works and so on. It makes it detect a lot of non public safety transmissions. In a couple of years our public safety will move to a LTE 700MHz system. Then it will probably be possible to detect any RF in that specific frequency band, and it probably will be pulsating at a specific rate.
One issue with Tetra, and probably other systems as well, are that mobiles reduce their transmit power when they are close to a tower and can go down to 10mW which makes it difficult to receive and detect until you are a few feet from the one that transmits.
/Ubbe
Isn't that article from 10 years ago?Not a radar detector but a radio detector. Heard about these in the UK , article says US band versions on the way.
'Police detector' monitors emergency radio transmissions | Fox News
'Police detector' monitors emergency radio transmissions
AB5ID
Member
AB5ID
Member
Thanks! Great info.
And many (more) don't. Here on the western slope of Colorado, most agencies on the state DTRS don't even have docks in their police vehicles. The officers use lapel speaker/mikes for the handheld radios on their utility belts. That includes our State Patrol.
wtp
Member
even my 396T got a P25 hit many years ago.
it is just rare that i ride around with close call on.
it is just rare that i ride around with close call on.
Similar threads
