FMN Or FM ?

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BOBRR

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Hello,

Using Sentinel and a 436.

Putting in some BAPERN frequencies for the Boston area.

RR shows them as FMN

But in Sentinel, it seems I can only select FM

Should I be putting in FMN ?
How ?

Thanks,
B.
 

jonwienke

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Yes. Sentinel option is NFM, not FMN.

Why not just copy from the main database? Sentinel has everything in RR if you update the database regularly.
 

BOBRR

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From OP:

Hi,

Oops, sorry.

Meant NFM

BTW: If I do change it in Sentinel, there does not seem
to be a pull down menu in the Modulation column.

Do I just type in NFM ? Or,...?

Thanks,
B.
 

BOBRR

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What Happens If FM Selected Rather Than NFM ?

Hello,

Using Sentinel with a 436.

If I have, e.g., FM selected where NFM is the correct modulation
scheme, what happens ?
Would I hear "anything" ?

Or, the reverse, where NFM is selected rather than FM ?

BTW: Is there any "general rule," or custom, regarding which types of stations are
FM, or NFM ?

Thanks,
Bob
 

ChrisABQ

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On the scanner, NFM or FM is merely the filter that is enabled. Selecting NFM narrows the filter bandwidth for narrowband frequencies. FM is a bit wider.
 

nd5y

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BTW: Is there any "general rule," or custom, regarding which types of stations are
FM, or NFM ?
Almost all Public Safety and Industrial/Business stations in the 138-174 and 450-470 MHz bands that are analog FM were required to use NFM (5 kHz deviation) on 01/01/2013.
See the FAQ at Narrowbanding - The RadioReference Wiki for more information on which types of stations and which frequencies are required to use NFM if analog or digital modes with less than 12.5 kHz bandwidth.

For a particular frequency in your area you can program it as both FM and NFM and decide which sounds best. You can't break anything by programming the wrong mode in a scanner and you will still hear stations if you program the wrong mode.
 

jonwienke

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Most digital is NFM, including P25, DMR, and most ProVoice (which can be FM). Business band is mandated to be NFM, public safety analog may be either, but is gradually migrating to NFM.

If you select NFM when FM is correct, the audio will be clipped and distorted on analog channels, Digital will not decode properly.

If you select FM on a NFM analog channel, you will have low audio level and potentially interference from adjacent channels. Digital will not decode properly.

As a general rule, start with NFM and don't change to FM unless you have problems decoding a digital channel or experience excessively loud and distorted audio on an analog channel.
 

jonwienke

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There is a dropdown. Click on the right side of the cell to see it.
 

ecps92

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And, altho ultimately exempted, the 470-512 aka T-Band were initially required to NB.

Here in the Boston area, many had already allocated the funds/grant $$, so they did Narrowband, as they also had to touch many of those same radios due to 450/460 frequencies in them. Some did not, and as Tom mentions below, the only true way [from a scanner perspective] to use FM vs NFM is to experiment yourself. See what audio is best, on a Freq by Freq basis. :cool:

Almost all Public Safety and Industrial/Business stations in the 138-174 and 450-470 MHz bands that are analog FM were required to use NFM (5 kHz deviation) on 01/01/2013.
See the FAQ at Narrowbanding - The RadioReference Wiki for more information on which types of stations and which frequencies are required to use NFM if analog or digital modes with less than 12.5 kHz bandwidth.

For a particular frequency in your area you can program it as both FM and NFM and decide which sounds best. You can't break anything by programming the wrong mode in a scanner and you will still hear stations if you program the wrong mode.
 

BOBRR

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For Jonwienke, et al: Drop-Down List In A Cell ?

Hello,

Thanks for help.

Having trouble getting the drop-down list in a Cell to show in Sentinel (BCD 436).

Want to be able to select, and possibly change, the Mode, on some older FAV lists I have.

"There is a drop-down. Click on the right side of the cell to see it."

When I click on a Cell (anywhere), with either the right, or the left, mouse button, the complete line
gets highlighted.

Can't seem to have only the particular Cell be highlighted, and the drop down list
appearing.

What specifically, am I doing wrong (as usual), and how do I get to the drop-down
list showing all the possible Modes for the Mode column ?

BTW: If RR shows P-25 for a particular source (like my local P.D.) is NFM the correct choice
to put in ?

Thanks,
Bob
 

jonwienke

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You have to be in the favorite list editor. Right-click on the Favorite List and select "Program Favorite List" from the pop-up menu. You can't edit anything (except to turn Avoids on and off) in the main Sentinel window.

And if something is in the RR database, you do not have to enter it into a favorite list manually. Just copy it from the main database. Right-click on the system in the database and select "Append to Favorite List" from the pop-up menu. Sentinel will ask you which favorite list.

And as I said before, ALL P25 and DMR is NFM. No exceptions.
 

BOBRR

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From OP For Jonwienke: A Bit More, Please. e.g, NFM vs. FMN ?

Hi,

Thanks for all the help; both now and in the past.
Really greatly appreciated. Sure is a lot to know, and at my age now I seem to miss a lot of the nuances.

Question: You say that P25 is always NFM. Great, our (Sudbury, Mass.) P.D. is P25, so I'll
set it to NFM.

Most of the BAPERN police channels for the Boston area say FMN.
FMN does not appear on the Mode pull down list in Sentinel.

What should these channels be set to, then ?

What is FMN ? Where and when should it be selected, etc. ?

Thanks again,
Bob
 

jonwienke

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NFM = FMN

Both refer to narrowband 12.5KHz channels.
 

BOBRR

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From OP: Re Previous Msg. (BAPERN Mode ?)

Hi,

Should have asked in previous Post:

What about all the BAPERN Freq's:

FM or NFM ?

Thanks,
B.
 

systech456

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as stated some scanners work better in wide or narrow to listen to a given system, however the system itself is narrow.
 
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