Question On Modes Please

BOBRR

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Joined
Dec 15, 2004
Messages
1,406
Location
Boston, MA
Hello,

In my 80's now, so please bear with me a bit.
A great excuse for most anything.

Are these Fred's NFM ?:

142.825
143.475
156.7

Are these USB ?:

3.053
11.196
20.135

And for a MIL Tac Channel: USB ?:

30.3

I always seem to have uncertainty regarding modes.
Is there some general rule of thumb for ?

Thanks for help,
Bob
 

mmckenna

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Jul 27, 2005
Messages
18,861
Location
LATA 722
Hello,

In my 80's now, so please bear with me a bit.
A great excuse for most anything.

Are these Fred's NFM ?:

142.825
143.475
156.7

The first few are probably military frequencies and are likely narrow band.
156.7 is a VHF Marine channel 14 and would be Wide Band. Marine VHF was not impacted by the narrow banding mandate.

Are these USB ?:

3.053
11.196
20.135
Maybe.

And for a MIL Tac Channel: USB ?:

30.3
If it's 30.3MHz, then it is very likely FM wide. But if it's military, they can pretty much do whatever they want.

I always seem to have uncertainty regarding modes.
Is there some general rule of thumb for ?

Thanks for help,
Bob
"The nice thing about standards is that there are so many to choose from".

General Rule of thumb is that there are rules, but there's a lot of loopholes.
VHF Low band is almost always wide band FM*
VHF High Band (150.100MHz to 174.000MHz) is almost always Narrow FM*
Marine VHF is currently wide band FM*, although there are plans in the books to make it narrow, and eventually digital, but don't hold your breath.
UHF band for commercial/LMR/Public safety is all narrow band.*
700MHz is narrow FM, but more commonly P25*
800MHz band is wide FM and a mix of whatever digital mode you have.*


*Your milage my vary. Not valid in some areas. Tax not included.
There are various FCC waivers on some frequencies that still permit FM Wide, like on some of the old VHF paging frequencies.
There are some FCC licensees that didn't pay attention to narrow banding.
There are lots of unlicensed users that are using whatever their cheap Chinese radio came with out of the box.
The Military does whatever the hell they feel like.
Inland there are some commercial users legally using VHF marine channels in narrow FM mode.
And a ton of other variations of the above.
As I said, the nice thing about standards is there are so many to choose from, and there are those that don't pay attention to standards.

How's that for a "rule of thumb"?
 

BOBRR

Member
Joined
Dec 15, 2004
Messages
1,406
Location
Boston, MA
Hi,

Just a quick thanks.
Appreciated.

Sure can get confusing, at least for me.

Regards,
Bob
 

n4jri

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Premium Subscriber
Joined
Jan 10, 2004
Messages
1,459
Location
Richmond, VA
Are these Fred's NFM ?:

142.825
143.475
138-144 MHz is an interesting range for the military. Could be NFM if land mobile, but could also be used by aircraft in AM mode. A particularly popular range with F-16's.

73/Allen (N4JRI)
 
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