AM, FM?

[OmensEdge]

I was wondering if someone could tell me which frequencies are designated for each band. I'm sure there's somewhere on the net that lists the info, but I can't seem to find it.

Just in case no one knows what I'm talking about. I'm asking what designates a frequency as AM, FM, SSB and such. I know the CB band and aviation are in AM. Where exactly do ranges start and end is what I'm trying to find out.

 

[Admin0140434]

idividual frequencies are different, but here is a general idea... ***NOTE: list from Uniden 246T manual***

25 - 27.995 AM

28 - 54.000 FM / NFM

108 - 136.975 AM

137 - 1300.000 FM / NFM



this doesnt include MILAIR frequencies (since the 246T isnt capable of MILAIR). MILAIR frequencies i believe are AM mode

 

[ka3jjz]

For the most part, UHF milair freqs between 225-400 Mhz or so are AM; however there are a few notable exceptions, particularly where satellites are concerned. The VHF milair section (138-144 Mhz) can be AM or FM depending on the whim of the user (the recent usage of the new splits by the Blue Angels is one example.

The 246T manual has one error in it, and I'm surprised Paul didn't catch it; the 10 meter ham band is generally not received in FM or NFM (even though the 246 probably has it set up this way). Freqs between 28.0-29.6 Mhz or so can be many different things (CW in the lower portion, data modes such as PSK31, SSTV, satellites and of course SSB). Between about 29.6 and the top end (29.7 mhz) are the 10 meter repeaters which are in FM/NFM modes. There is a little AM used in the 28.0-29.0 mhz range, but not all that often

To me it makes no sense to make a scanner that can cover the 10 meter band and not include the correct modes found there; better to start at 29.5 (some satellites can be found there) and continue upward from there.

73s Mike
'

 

[OmensEdge]

Thanks for the replies. Maybe I should point out that I'm using the WIN96 software to program a scanner for a friend. It gives the option to enter the band and sometimes I have no idea what to enter. Then again, when I would enter an incorrect band on my Pro-96, it would automatically correct itself whenever a transmission would be picked up.

Here's the thing - I have no idea if the scanner will allow itself to correct the problem if it has been programmed with the software. Also, the scanner is a Pro-2096 I'm told instead of the handheld like I had. Maybe I should ask elsewhere. I was just hoping there might be some sort of a table on the net somewhere.

See...I was just programming a local ham band here which would be AM, right? Then I notice the same frequency is also listed under the Skywarn frequency in this area and it designates it as an FM band frequency. Will the scanner not stop on a particular frequency if the band is wrong when I programmed it?

 

[Admin0140434]

dont get us wrong... the 246T manual is a general idea of what modes are for certain frequencies, whether your using a 2096, 96, 246T, 296D, etc

 

[loumaag]

See...I was just programming a local ham band here which would be AM, right? Then I notice the same frequency is also listed under the Skywarn frequency in this area and it designates it as an FM band frequency. Will the scanner not stop on a particular frequency if the band is wrong when I programmed it?

I am guessing that this is in the two meter Ham band and most communication in that band is on FM. Yes there is some weak signal work on SSB and even AM and digital modes, but nothing that you should bother with on a scanner.

BTW, the radio will stay at whatever mode you set it (either with the software or by hand), the only auto change it makes is on detection of a P25 digital signal, then it will change from FM or MOT to DG.

 

[ka3jjz]

Quite right, Lou. The same can be said of 432 Mhz as well as the low end of 6 meters (to about 51.5 mhz or so, depending on local conventions); in both cases, a similar setup exists; CW, weak signal work, digital and in the 432 mhz case, some ham satellites as well. However, I believe we are the only region that has 4 mhz on 2 meters; the other parts of the world stop at 146 mhz or so.

That's something that would be really valuable to a newcomer; a scanner that sets the correct mode for each freq range, particularly in the ham and UHF milair bands, subject to user correction of course. I wouldn't at all be too adverse to excluding those bands for which the scanner can't cover the mode, either (like the 10 meter range I mentioned earlier). But I suppose it would be tough with any regional changes, like for 2 meters.

73s Mike

 

[Al42]

See...I was just programming a local ham band here which would be AM, right? Then I notice the same frequency is also listed under the Skywarn frequency in this area and it designates it as an FM band frequency. Will the scanner not stop on a particular frequency if the band is wrong when I programmed it?

Hams, unlike all other users, are are allowed any of a number of modulation types, many times on the same frequency, so there's no "type" for a ham band - there are types for many segments of ham bands, such as FM on 144. 5(roughly) to 147.995. Skywarn operations on 2 meters are conducted in NFM. But you have to know the activity on the segment of the band - just the band isn't enough. http://www.csgnetwork.com/hamfreqtable.html will give you an idea of the possibilities from 28 MHz (it actually covers from 1.8 MHz) to 450 MHz.

Oh, aircraft normally operate on AM so that, even if there's interference, after-the-fact signal processing can isolate the transmission that's wanted. (For accident investigation purposes.) FM receivers, when receiving signals of different strengths, normally only receive the stronger one.

 

[ka3jjz]

That's true to a point; local conventions often dictate minor changes in what is allowed on a frequency. And the FCC Part 97 rules dictate what frequencies (and by extension. modes) are allowed to be utilized by license class. For example, most CW ops would frown on someone running a 1Kw sideband station on 7040 khz. Even if the guy was an Extra, it would be strongly discouraged.

73s Mike

 

[loumaag]

That's true to a point; local conventions often dictate minor changes in what is allowed on a frequency. And the FCC Part 97 rules dictate what frequencies (and by extension. modes) are allowed to be utilized by license class. For example, most CW ops would frown on someone running a 1Kw sideband station on 7040 khz. Even if the guy was an Extra, it would be strongly discouraged.

Mike,
I think the FCC (assuming US band usage) would frown on this example also. :shock:

Since only RTTY and DATA (includes CW) are allowed between 7.000 and 7.075 MHz by CFR 47; Sec. 97.305, SSB is not allowed down there. Now, if you would have grabbed 7080 KHz as an example, it would have been better. :wink:

 

[Al42]

That's true to a point; local conventions often dictate minor changes in what is allowed on a frequency. And the FCC Part 97 rules dictate what frequencies (and by extension. modes) are allowed to be utilized by license class. For example, most CW ops would frown on someone running a 1Kw sideband station on 7040 khz. Even if the guy was an Extra, it would be strongly discouraged.

Mike,
I think the FCC (assuming US band usage) would frown on this example also. :shock:

Since only RTTY and DATA (includes CW) are allowed between 7.000 and 7.075 MHz by CFR 47; Sec. 97.305, SSB is not allowed down there.

Of course a lot of DX ops don't seem to care - I see SSB on my waterfall often enough.

 

[nd5y]

In ITU region 2 (N & S America) the 40m band is 7.0 - 7.3 and in the rest
of the world it is 7.0 - 7.1. That is the reason you hear SSB in what is
the CW/Data subband in the US.

 

[Voyager]

That's true to a point; local conventions often dictate minor changes in what is allowed on a frequency. And the FCC Part 97 rules dictate what frequencies (and by extension. modes) are allowed to be utilized by license class. For example, most CW ops would frown on someone running a 1Kw sideband station on 7040 khz. Even if the guy was an Extra, it would be strongly discouraged.

Mike,
I think the FCC (assuming US band usage) would frown on this example also. :shock:

Since only RTTY and DATA (includes CW) are allowed between 7.000 and 7.075 MHz by CFR 47; Sec. 97.305, SSB is not allowed down there.

Of course a lot of DX ops don't seem to care - I see SSB on my waterfall often enough.

Does your waterfall confirm that it is coming FROM the USA? There are other countries with SSB ops allowed there. In the USA, it is downright illegal.

Joe M.

 

[Al42]

Does your waterfall confirm that it is coming FROM the USA? There are other countries with SSB ops allowed there.

I thought we were talking about courtesy. The PSK31 "band" is only about 4 KHz wide.

 

[Voyager]

Does your waterfall confirm that it is coming FROM the USA? There are other countries with SSB ops allowed there.

I thought we were talking about courtesy. The PSK31 "band" is only about 4 KHz wide.

Nope - there is an FCC RULE that prohibits SSB use in the USA below 7150 kHz (7.150 MHz) on the 40M band.

It IS Allowed in some territories and posessions that are in different zones from the continental USA, so it is possible to hear US-issued callsigns there, but any SSB transmissions coming from the continental USA are a definite 'no-no'.

Joe M.

 

[OmensEdge]

Hmm. Now I'm just confused. How about this - I'll give you guys the short list of frequencies I have and you can tell me if they should be designated as AM frequencies or not. These are all HAM band frequencies:

51.7200
145.1700
146.8400
444.5000
442.8500
147.0000
146.7200
147.0400
444.6500
145.3100

Again, I just need which band I need to designate these under in WIN96. Thanks!

 

[Joseph11]

I believe all FM.

 

[OmensEdge]

I was thinking that too going by that list for the 246T. I remember though that I had chosen AM mode when I had the majority of these programmed into my Pro-96 and I was still receiving transmissions on the channels. Does it not matter what mode you have them under?

 

[Voyager]

Hmm. Now I'm just confused. How about this - I'll give you guys the short list of frequencies I have and you can tell me if they should be designated as AM frequencies or not. These are all HAM band frequencies:

51.7200
145.1700
146.8400
444.5000
442.8500
147.0000
146.7200
147.0400
444.6500
145.3100

Again, I just need which band I need to designate these under in WIN96. Thanks!

All FM. All repeater outputs, in fact. Judging by the frequencies, I would estimate in MI.

Joe M.

 

[OmensEdge]

That would be correct. Thanks for the info!