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Frequency Scanners
Scanners can monitor a variety of things: police, fire, EMS, and even air traffic. Although they can't transmit, they are still very useful.
409 Questions
What are the scanner frequencies for lake okeechobee Florida?
For a comprehensive database of active frequencies and systems in your area, and a lot of other useful scanning information, visit the related link below.
A conventional VOR (CVOR) has three Amplitude Modulated (AM) signals encoded on a VHF carrier:
1) a 30 Hz variable (VAR), which is modulated by the antenna, not the transmitter;
2) a 9960 Hz subcarrier, which is in turn frequency modulated (FM) with a 30 Hz reference (REF) signal;
3) and a voice / identifier channel, which includes 1020 Hz "Morse code" identifiers and aural voice signals.
The 9960 Hz subcarrier and the voice / identifier channel is the same for CVOR and Doppler VOR (DVOR). The explanation for the generation of the VAR signal offered below applies to CVOR. For explanation of the VAR signal of DVOR, see http://wiki.answers.com/Q/Explain%20both%20doppler%20aswell%20as%20convenional%20vor.
The VAR signal is created by spinning a slightly directional antenna at 1800 rpm (30 revolutions per second). The phase of this 30 Hz signal is variable, dependent on the location of the receiver.
To determine VOR bearing, another 30 Hz signal is required. The REF signal is perceived as being the same phase regardless of position of the receiver relative to the VOR.
Here is the problem: the VAR 30 Hz signal is already modulated on the carrier. If the REF 30 Hz signal is modulated onto the carrier without processing, a receiver would find two 30 Hz signals (just one signal if REF and VAR signals are in phase). How would the receiver know which signal is the REF and which is the VAR?
To get around this problem, the VOR takes a 9960 Hz carrier and frequency modulates this carrier with the REF 30 Hz signal. The modulation index is 15, meaning the 9960 carrier has a deviation of 450 Hz (30 Hz times 15). In other words, the subcarrier varies between 9510 Hz to 10410 Hz (9960 +&- 450 Hz). This frequency excursion occurs 30 times per second (30 Hz). The subcarrier signal spectrum does not overlap with the spectra of the VAR or aural signal; therefor it can be amplitude modulated on the RF carrier.
The reason for frequency modulation of the REF signal on the 9960 carrier, as opposed to amplitude modulating the REF signal, is that the AM detector in a VOR receiver would still output two 30 Hz ambiguous signals and a 9960 signal, all summed together.
The VOR instrumentation processor takes the detected VOR signal (called VOR composite video signal (COMP)), and processes the signal as follows:
1) COMP is processed through a low pass filter that preserves 30 Hz to get the VAR signal;
2) COMP is processed through a high pass filter to reject the VAR and aural signals, then an amplitude limiter, and then though an FM detector to get the REF signal. The FM detector could be a discriminator (used in the bad old days), or a phase lock loop (used in modern equipment);
3) COMP is not processed by VOR instrumentation; however it may be filtered to please the listener, i.e. range filter (1020 Hz bandpass), voice filter (200 to 3000 Hz bandpass). VOR bearing (magnetic direction away from the VOR) is simply the phase angle of the VAR signal minus the phase angle of the REF signal.
Why 9960 Hz and not something lower? The baseband spectrum of the whole VOR signal consists of a reasonably narrow 30 Hz signal (VAR), the aural / ident signal (approximately 200 Hz to 3000 Hz), and the 9960 subcarrier (9510 to 10410 Hz). No overlap can be allowed. Also, the receiver has to separate the signals; therefore a significant gap between the signals is provided.
A Doppler VOR varies from a conventional VOR in that the VAR channel is 30 Hz frequency modulated instead of 30 Hz amplitude modulated. The spectrum of the CVOR REF signal is a narrow signal at the RF carrier frequency (fc) (between 108 to 117.95 MHz), and two side bands, one at fc + 30 Hz and the other at fc - 30 Hz. The DVOR REF signal has the same spectrum components as the CVOR REF signal, with the addition of sidebands at (plus and minus) 60 Hz, 90 Hz, 120 Hz ... and on (diminishing in amplitude). The VOR receiver does react to the sidebands at 60 Hz and above because the VAR signal is separated by a low pass filter; therefore it does not matter to the receiver whether the signal comes from a CVOR or DVOR.
What is squelch on a police scanner?
The high frequencies used on scanner channels cross over into the area where there is a lot of random "white noise", a harsh, loud "hiss". Squelch turns the gain down below the hiss, but hopefully not below the signal. It has to be adjusted carefully, otherwise you eliminate the signal along with the noise.
How do you find frequency information for your area?
To find frequency information, check out Policescanners.net. PoliceScanners.net is a resource for the radio community, as well as anyone looking to get involved in the hobby or in need of a scanner as a communications tool. Policescanner.net provides its users with scanner comparisons, a scanner database for every county in the nation, programming options, and other features to help scanner hobbyists decide the best scanner for their location and situation, with just a few simple keystrokes.
Where can you find local police scanner frequencies for Arkansas?
For a comprehensive database of active frequencies in your area, along with a lot of useful scanning information, visit:
www.RadioReference.com
How accurately does a police scanner measure the speed of a vehicle?
Modern police scanners are accurate to with about 3 mph.
Scanner frequency Kentucky Floyd county?
There are several different scanner frequencies for Floyd County in Kentucky. The 911 dispatcher frequency is 154.80000. Law enforcement is 154.81500, 155.31000 or 155.06250.
Dose any out there know how old this radio shack scanner a pro 2018 or how you can get a manual?
The pro 2018 two hundred desktop scanner's manual has a date on it as 2002.
The manual can be found at the Radio Shack website listed as a click able link below in the Related Links section. The manual is in PDF format.
What does a scanner operate similar to?
A scanner operates similarly to a photocopier, as both devices capture physical documents and convert them into a digital format. Like a camera, a scanner uses light to capture images of the document, translating the visual information into data that can be processed and stored on a computer. Additionally, it shares similarities with a fax machine, as it transmits information electronically after scanning.
How do you program a regency scanner model mx-3000?
To program a Regency MX-3000 scanner, start by turning on the device and accessing the menu. Use the keypad to navigate to the programming section where you can input frequencies manually or enter specific channels. You can also use the software provided by Regency, if available, to make programming easier via a computer connection. Finally, save your settings and ensure the scanner is set to the desired mode for receiving transmissions.
How do you peak tune you Uniden pc68xl?
To peak tune your Uniden PC68XL, first, ensure you have the proper equipment, including a wattmeter and an SWR meter. Open the radio and locate the adjustment pots on the circuit board for the modulation and output power. Using the wattmeter, adjust the output power pot to achieve the desired output (typically around 4 watts for AM), and then adjust the modulation pot to increase audio clarity without distortion. Make sure to test the radio after tuning to ensure it functions properly and meets your communication needs.
Will a US radio channel scanner work in the UK and is it legal... the scanner is a GRE PSR-500?
A US radio channel scanner like the GRE PSR-500 may work in the UK, but it depends on the frequency ranges it covers. However, using it to listen to certain communications, especially those that are encrypted or used by emergency services, can be illegal under UK law. It's important to check local regulations regarding scanning and ensure compliance to avoid any legal issues. Always verify the specific frequencies you'll be listening to and their legality in the UK.
Where can you find free scanner frequencies and channels for Hopkins county?
You can find free scanner frequencies and channels for Hopkins County by visiting websites like RadioReference.com, which offers a comprehensive database of frequencies and user-contributed information. Additionally, local amateur radio clubs or community forums may provide updated frequency lists. Social media groups focused on local emergency services or scanner enthusiasts can also be valuable resources. Lastly, mobile apps like Scanner Radio can offer live feeds of local channels.
How do you program Z 45 regency scanner?
To program the Regency Z30
TURN UNIT "ON"
1. Press "MANUAL"
2. Enter the frequency you want, example 162.475
3. Press "ENTER"
The display will show "Ch_" with the _ (underscore) flashing
4. Enter the number of the channel where you wish to store the frequency.
Note: channels 1 thru 9 must have a zero before them, example 01, 02,........ 09
If you want to add more frequencies at this time, got to step 2.
To lock out a channel, press "SCAN" and while the unit is scanning,enter the channel number. Repeat this action to unlock a channel.
To increase or decrease the scanning rate, press the "SPEED / ENTER" key while the unit is scanning.
To create a delay after a transmission, press the "DELAY" key while the unit is scanning.
You can change the display by pressing the "CHANNEL / DISPLAY" key.
There are 3 choices: display only the channel number, only the frequency,or alternate displaying the channel number and the frequency.
