UHF Radio Characteristics

the original text.)

Does anyone know what does "channel step size" for UHF radio

Hai I cant Understand U R Quasition

What is the use of this radio, is it for two way communication for business or something like that. Usually I would think the channel step size would refer to the amount of spacing between channels, I think those would be standard for most two way communication equipment. It could also refer to the channel bandwidth, although I would think they would call that channel bandwidth. Can you ask the manufacturer of the radio what they mean by that term?

IIRC 25 but now 12,5 is available.

Step size means channnel sapcing. It is regulated by RF control in each country. Typical channel spacing is 25Khz, 12.5KHz and recently the US (FCC) moving into 6.25KHz. Evanbtually 25KHz will be banned.

There are more two, 8.33 kHz and 5 kHz.

Caner

Hello

The previous comments are appropriate but perhaps I can go a bit farther for you.

Each country will have a set of specifications for spectrum use. They are normally coordinated from country to country by international treaty but there are some countries that don't subscribe or choose to participate in the otherwise fairly standardized usages. You must determine what your local standards and specifications are.

Generally, usage is broken out into "broadband" or "narrow band". In the older analog world, "narrow band" could go down to less than 3000 Hz bandwidth (telephone audio quality) because information content in the human voice, and consequently reliable voice communication can be accomplished in that bandwidth. Mobile communication radios (like taxis, busses, police cars, etc.) use these narrow bandwidth channels.

Again, analog usage for systems requiring full audio fidelity or video--FM commercial radio for instance will require 15kHz of bandwidth or more, TV even more, depending on scan rate and how the audio information is placed on the carrier, whether there are subsidiary (SCA) channels for things like subtitles, muzac services, pager services, etc.

The advent of various digital modulation methods (TDMA, CDMA, GSM, FSK, QPSK, etc.) are all basically designed to allow more information to be passed in a given bandwith...and they affect how bandwidth is allocated.

The higher you go in frequency the more channels can be allocated between any two numbers so step width (read channel size--which also depends on type of usage as noted above) will vary between one part of the spectrum and another. Radio waves behave differently at different frequencies. That is why AM radio and Short Wave radio and FM radio and Satelite, TV, cell phone, and etc. services are located as they are in the frequency spectrum.

Bottom line is that "channel step size" depends on the type of service, the physical attributes of the elctromagnetic spectrum, and ultimately, upon what your particular establisment of bureaucrats has decided to allocate.

The simple answer is to read the operators manual to determine what standards your particular device supports. I don't think I have said anything stupid. Someone please correct me if I have.

Lonnie

Can I guess that it might be amateur radio related? When you switch up or down in frequency, it is done incrementally in steps. If you have step size set for 25 KHz for example and start at 440 MHz, each time you ''click" the frequency selector, it will change in 25 KHz increments... such as 440MHz, 440.025 MHz, 440.050 MHz etc. If you want to go to 440.030 MHz, you are out of luck. So change the channel step size to 5 KHz. If you want to go from one end of the band to the other, it means alot of knob twisting, but you get much finer tuning. If you use certain frequencies frequently, put them in memory. Then you can get to them with very little knob twisting.

73's

Bill

Keep in mind the application of "Spread Spectrum" radio link methods that have found application in the UHF frequency spectrum for wireless industrial data communications. The concept of discrete channel step size doesn't really apply to this type of technology.

Art Mengon JR. Electrical Engineer

Mengon Enterpises LLC.

WA9TER (40 yr license holder)

mengonae@att.net

I hadn't thought about that Art... but there, frequency selection is done entirely by the radio(s).

I am awfully curious what the application is in this case... whether ham, commercial, or whatever. Maybe the originator of the thread will tell us.

For what it is worth, I will be coming up on my 50th year in ham radio in July. What is it about ham radio that makes us get into professions such as ours? HI!

73's de

Bill NW7L