PRO-97 and trunking
Yes I am very new to scanning. I recently purchased a Pro 97 and am trying to program a local frequency.
Hello and welcome to RadioReference.com. In the olden days everyone simply used frequencies; we now call that "conventional". What you are trying to monitor is a "trunked radio system" (TRS).
The primary control channels are 854.61250c 856.73750c 859.73750c. I have programmed these in and changed the mode to MO.
It sounds like you are programming these manually. That's OK, but keep in mind you will need to set each frequency to "MO" (which you state you've done) as well as the BANK. After you've programmed in the 4 frequencies, press FUNC TRUNK. Next you may need to press the MODE button several times to select the correct mode for the bank of MO.
On one of the control channels, I see the MOT: Sys-4210 95%. Every so often that line will change to MOT: and a number which I assume is the talkgroup. Why do I hear a loud buzzing noise instead of the conversations? Thanks for help, please excuse my lack of knowledge I'm still new at this.
The buzzing sound is data being sent over the control channel. Other frequencies on the system (not likely those you have programmed) will have parts of the conversations. In order to "trunk track" conversations you MUST be in SCAN mode. If you're getting 95% from the control channel that is great. You should not have problems getting the conversations.
Note that there are two basic ways to operate the PRO-97 with regards to trunked systems. They are called "open" and "closed" mode. In open mode, the scanner will stop on ANY talkgroup that is active. In closed mode, the scanner will only stop on a talkgroup which has been programmed, is in a sub-group which is on and is not locked out. While you are scanning, under the digit on the display which represents the bank you are using, there will be a "+" or a "-". + indicates the bank is in open mode, - indicates it is in closed mode. To toggle the bank, press FUNC DELAY while in MAN mode.
The manual that comes with the scanner is one of the worst in history. There is an online version which is much easier to understand. You can also find more info on that scanner here:
Pro-97 - The RadioReference Wiki