New to this: Two questions about frequencies..

[MarcInIllinois]

Hi all,

Just joined up yesterday, have a Pro-97 I purchased new from ebay and really liking it so far. I have two questions which I can't seem to find the answers to using the search:

1. In the frequency listings in the database (non-trunked), I see sometimes a 2nd freq. listed as "input", what is this one used for?

2. What is a "PL" tone or frequency and why do I need it?

I'm in Southern Illinois about 80 miles SE of St. Louis MO.

thank you.

 

[safetyobc]

The input frequency you will likely not need. It is the frequency that is inputed to the repeater or transmitted from the radio to the repeater. It will only carry a very short distance and unless you are close to the transmitting source you won't hear any traffic. The output frequency is the one the repeater is sending and carries many miles. I use some of the input frequencies for my local Fire and Police because if they go to "talk around" they are using only the input freq and not using the repeater. This is usefull if the repeater is damaged or if they just simply don't want to go through the repeater. This doesn't happen in my area maybe once a year or so but it is a possiblity. I only do this for local pd and fd's though.

The PL Tones are tones if inputed into the scanner will keep you from receiving interference from other agencies that are fairly close using the same frequency. For instance if your county uses 155.4000 and a pl tone of 123.0 and another county 80 miles away uses 155.4000 and a PL of 179.9, on a good day you may hear traffic from the county that is 80 miles away. To stop the interference you entere the PL tones for your county and it will block the other signal. You can input the same frequency with differenct PL tones so that you will still hear traffic from the other frequency if you are interested in hearing it.

Hope this helps.

 

[MarcInIllinois]

Hi

Yes that helps greatly, thanks!

One other thing; do either the pro-95 or pro-97 support the entry of these PL tones? If so, how would one enter them?

thank you!

 

[safetyobc]

Yes the 97 does I know. I don't have a 97 so I can't help you on that. I do know you can set it to search for the tones if you are unsure of the exact tone. Your manual should explain everything to you about inputing the tone. If you don't have the manual you can access it online at radio shack or to make it simple just click on this link Pro 97 Owners Manual

You will see the info you are seeking on pages 31 - 33 under CTCSS and DCS. (NOTE: PL/DPL is just another name for CTCSS and DCS so don't let that confuse you)

I didn't see the CTCSS and DCS on the 95 but the here is the Pro 95 Owners Manual

 

[Admin0140434]

...pro-95 support the entry of these PL tones?

no, the 95 doesnt support PL/DPL

 

[mn2deep]

I use some of the input frequencies for my local Fire and Police because if they go to "talk around" they are using only the input freq and not using the repeater. This is usefull if the repeater is damaged or if they just simply don't want to go through the repeater.

For true "talk around" (not keying up the repeater), the output freq would be used to transmit and receive. If your local agency uses the input frequency as transmit and recieve on "talk around" they are still keying up the repeater.

Just my 2 cents

 

[Colin9690]

Basically for a beginner, just listen to the output frequency for now. As you get more into the hobby, you will want to expiriment with listening the the input freqs to see if a transmitting radio is close to you or not. Anyways, to keep it simple, just listen to the output freqency. Have fun with your new scanner!

 

[MarcInIllinois]

I think that's going to be better, keeping it simple for now

thank you for all the help.

 

[Al42]

For true "talk around" (not keying up the repeater), the output freq would be used to transmit and receive. If your local agency uses the input frequency as transmit and recieve on "talk around" they are still keying up the repeater.

Unless the portables are programmed to use a different PL, or no PL, on talk around. But input and output each have their bad points - talk around (FG) should be on a separate frequency.

 

[kb2vxa]

Hi guys,

"For true "talk around" (not keying up the repeater), the output freq would be used to transmit and receive. If your local agency uses the input frequency as transmit and recieve on "talk around" they are still keying up the repeater."

"Unless the portables are programmed to use a different PL, or no PL, on talk around. But input and output each have their bad points - talk around (FG) should be on a separate frequency."

To clarify, the primary "bad point" of using a repeater input for simplex "talk around" is causing interference to the users of the repeater. Secondary is it's a technically complicated way of doing something simple like switching the transmit frequency. Normally the output is used because it's no matter if the repeater "steps on" a casual chit-chat, (another bad point) otherwise important comms are conducted on a simplex frequency or in some cases the output of a distant repeater (a secret channel, ha ha) not likely to be monitored by scanner buffs.

Before trunking "user groups" would use different PLs on a common repeater set up for more than one tone on the input and sometimes both input and output. This was only done on low traffic repeaters or if the likelihood of two or more groups being active at the same time was minimal. There were some EMS repeaters like that and such use of commercial repeaters is still fairly common. The mobile unit employs a hang up switch to disable the PL receive when the mic is off hook in addition to a switch on the control head. The user simply picks up the mic and pauses to listen for other users before transmitting. The "squelch" or "monitor" button on a hand held performs the same function and in some cases it's a switch on the top of the unit marked "PL on-off".

 

[safetyobc]

Sorry. I guess I was wrong.