- published: 06 Dec 2014
- views: 85960
Very high frequency (VHF) is the ITU designation for the range of radio frequency electromagnetic waves (radio waves) from 30 MHz to 300 MHz, with corresponding wavelengths of ten to one meters. Frequencies immediately below VHF are denoted high frequency (HF), and the next higher frequencies are known as ultra high frequency (UHF).
Common uses for VHF are FM radio broadcasting, television broadcasting, two way land mobile radio systems (emergency, business, private use and military), long range data communication up to several tens of kilometres with radio modems, amateur radio, and marine communications. Air traffic control communications and air navigation systems (e.g. VOR, DME & ILS) work at distances of 100 kilometres or more to aircraft at cruising altitude.
VHF was used for analog television stations in the US, and continues to be used for digital television.
VHF propagation characteristics are suited for short-distance terrestrial communication, with a range generally somewhat farther than line-of-sight from the transmitter (see formula below).
Basic VHF and UHF Fundamentals Antennas are a very important component of communication systems. By definition, an antenna is a device used to transform an RF signal, traveling on a conductor, into an electromagnetic wave in free space. Antennas demonstrate a property known as reciprocity, which means that an antenna will maintain the same characteristics regardless if it is transmitting or receiving. Most antennas are resonant devices, which operate efficiently over a relatively narrow frequency band. An antenna must be tuned to the same frequency band of the radio system to which it is connected, otherwise the reception and the transmission will be impaired. When a signal is fed into an antenna, the antenna will emit radiation distributed in space in a certain way. A graphical representa...
An introduction of how to turn on, set and use a VHF radio. Lesson provided by Mike Whitehouse, senior sailing instructor with the Canadian Yachting Association.
VHF vs UHF - What's the difference We often get calls pertaining to Two-Way radios and our asked what is the difference between UHF ( Ultra High Frequency ) and VHF ( Very High Frequency ), well in today's video we hope we can help clarify and explain the difference between these two radio frequencies. More or less just a small increase of electromagnetic waves but also the length and duration of the signal. I've taken the liberty of providing a variety of other links below that might help you to further understanding this topic. As well I've attached a link that takes you directly to our website where we offer phenomenal pricing on just about every two-way radio battery to date. As well our house brand UHF DSR-590 Two- Way radio. Please Like, Subscribe and Comment with any question...
http://features.boats.com/boat-content/2013/05/video-how-to-use-a-vhf/ For more videos, visit www.boats.com. Your VHF radio is your lifeline to the outside world in case of emergency. So you gotta make sure you're using it right. The first thing you'll need to do is adjust the squelch. This is pretty simple: just turn it until it hisses, and then back it off until the hissing stops. That will eliminate all the unnecessary static. Tune to the channel you want, and then take the microphone and hold it at a 90 degree angle to your face. Speak slowly and clearly as you key the mike. Okay, now, let's make sure the radio's working properly by doing a radio check. First, tune to a station that's an open frequency, like channel 68. Then repeat three times, "Radio check, radio check, radio che...
Routine voice call using a Marine VHF DSC radio http://www.seavoice-training.co.uk/
Possibly the simplest possible pulsed beacon transmitter. Video describes where I got the circuit from, modifications to make it light dependent and complications along the way. I then do a range test on a local beach and get a surprising distance for a 1 transistor circuit powered by 1 x AA battery. The beacon operates just below 37 MHz using a commonly available 36.864 MHz crystal. In Australia frequencies around this are allocated to 'low interference potential devices' with a 100mW EIRP power limit. This transmitter would have an output of a few milliwatts only.
Chorus:
Girl I get dat cold sweat
Creepin' up on me
I ache when you shake it
Girl I'm just a freak
Yeah, you set dat cold sweat
Trippin' on me
Burnin' with the fever
Girl you're killing me
Girl you're kinda freaky
Got something 'bout your smile
And when you bounce it up and down
I can't believe my eyes
I got to give you respect
Cos you know how to tease
Keep on walking I'll keep talkin'
You would not believe
Bridge:
What I would do
With a girl like you
Keep your body rockin'
I ain't gonna stop I just want you
And you know
It's shockin' when you rock it
I'm a sick, sick man cos
(Chorus)
Girl I'm just a freak
In need of therapy
I count the ounce in every bounce
And I just want to feast
I love the way you work it
I love the way you grind
Ya got da funk in every pump
If you could read my mind
Bridge
(Chorus)
Down
You're burnin' me down (x3)
I love the way shake now
Love the way you break now
Keep it comin' baby
I don't wanna hesitate now
You got me hooked every look makes me freeze
180 degrees you make me buckle at my knees
Crazy rump shaker sexy move maker
Baby bring it on
Better sooner than later
I feel a cold sweat creepin' up on me
We gotta get it on
Tell me what it's gonna be
(Bridge)
(Chorus until fade)