i just bought the uniden bct8, and i read somewhere that it cant pick up digital frequencies. im new to this whole radio thing, so i have absolutely NO idea what im doing, but are digital frequencies FM, and analog frequencies AM? i live in sheboygan, and i found a website that gives out sheboygan frequencies, but it has FM next to them, is this the reason i cant hear anything on my scanner? help please!
Your scanner is analog only. All Public Safety radio transmissions in your area are FM. However, some are digital protocol and/or encrypted and your scanner will not receive those signals as anything more than a loud buzz.
Basics: Think of the
frequency of operation as you would TV channels. As you select TV channels in sequence from low to high, you are stepping up in frequency. The frequency is the center path of the signal. There are several different types of
Modulation that can be utilized on a frequency. The most common are Amplitude Modulation (AM) and Frequency Modulation (FM). Aircraft frequencies use mainly AM. When two AM signals on the same frequency occur at the same time, a 'heterodyne' (or tone beat frequency) is produced at the receiving station. In the case of aircraft frequencies, this was planned that way so air traffic contriollers could HEAR if more than one aircraft was transmitting at the same time and not loose track of an important message. If two aircraft transmit at the same time, the controller will hear the beat tone and will make certain that he or she contacts both pilots.
Most public Safety agencies, businesses, and government use FM. There are several types of FM modulation protocols - (the method of processing audio sound). Analog - which is a conventional means of basic speech and tone processing and Digital - which converts the voice or tone into a 'computer' based format that an analog receiver can not process. Within the Digital formats, there are any number of manufacturer proprietary methods of processing their digital signals - and most variations between manufacturers are not compatable with each other. This was done for marketing reasons, so an agency using a certain brand of equipment must stay with that brand in most cases.
Your scanner receives ONLY the non-digital analog voice and tone signals. Look through the DATABASE at the top of the main page for frequencies in your area. If the notations in those lists specify P-25, etc., your scanner will receive the frequency, but NOT the modulation component of the signal. Also, if there are still any CONVENTIONAL Analog Trunked Radio Systems in your area, your scanner can be programemd for all the frequencies in that trunked system and you can check the database here at R-R for the "talk group" codes to add to your programming. That will get rid of those transmissions that are not of interest to you and just allow your scanner to receive what you wish it to receive. Consult your owner's manual for the method of programming ANALOG Trunking data.
Hope that helps you just a bit...
