| Author |
Message |
    
Creator
Junior Member
Username: Creator
Post Number: 35
Registered: 1-2004
| | Posted on Tuesday, February 24, 2004 - 12:24 am: | 
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Got a radio that also transmits on FM, the DX 95T.
(1) I thought while transmitting on FM, it would'nt have a steady carrier like AM, but rather it would be more like transmitting on SSB with the carrier power getting out during modulation, was I wrong?
(2) If so, does 50 watts on FM transmit farther than 50 watts on AM?
(3) Can I transmit on FM on the standard CB channels, what would the CB'ers hear if I did?
Thanks,
Rob
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Ryan
Member
Username: Ryan
Post Number: 65
Registered: 11-2002
| | Posted on Tuesday, February 24, 2004 - 1:07 am: |
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1. FM is like am kinda, but instead of modulation, you have deviation as your method of injecting audio into the signal. should be minimal if any swing
2.50 watts on both modes will be close, but AM is a better mode for pulling out stations in the fringe due to the capture effect that FM mode has
3. yes you can, not legally, but some people could hear it, but not many ops use FM in the USA so chances are slim to none of actually making a qso. |
Alsworld
Junior Member
Username: Alsworld
Post Number: 769
Registered: 1-2002
| | Posted on Tuesday, February 24, 2004 - 1:47 am: |
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Creator,
1) FM will go to full power and stay there, i.e. no swing and virtually no movement on the radio needle once the mic is keyed.
2) 50 watts pretty much equals 50 watts, but on FM it goes there immediately, whereas sometimes AM gets there via PEP. If your radio swings to 50 watts on AM, there will be little noticeable difference from audio portion of the receiving end. Receiving end S units will read different being FM is full strength and AM reaches there with carrier plus modulation.
3) It's illegal to transmit on FM within the allocated CB frequencies. Yes it is physically possible, but is usually hard to understand if you are in the other mode, but not quite as hard as SSB.
I have played with FM a bit and at longer groundwave distances, it begins to get static as the signal gets weaker. AM seemed to work better for us then (SSB worked the best but I'm only comparing AM to FM). I realize that contradicts my #2 above. Closer distances, FM is nice where you can really use your squelch as designed.
Of course, we were only testing to ensure FM worked  .
Alsworld |
Bruce
Senior Member
Username: Bruce
Post Number: 1010
Registered: 9-2003
| | Posted on Tuesday, February 24, 2004 - 5:26 am: |
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Most know here im the 10 meter FM-A-Holic so when it come to fm i can answer your questions.
1) range on AM/FM are about the same. And FM will show as a steady carrer like AM.
2) FM can be used on regular cb channels but it's not a good idea the AM cbers will hear you but you will only hear muffled audio from them.
Now remember FM is ILLEAGAL on CB not on 10 meters ( if your licensed ) and the fm calling frequency in 29.600 for licensed HAMS...... so it's also a good idea if your going to use it to find a frequency that a group is all ready using FM there is some safety in numbers |
Barracuda
Intermediate Member
Username: Barracuda
Post Number: 190
Registered: 3-2003
| | Posted on Tuesday, February 24, 2004 - 1:50 pm: |
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FM is illegal on 11 meters CB. It is the standard mode on FRS,GMRS and MURS CB.
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Freebander
Junior Member
Username: Freebander
Post Number: 28
Registered: 10-2003
| | Posted on Tuesday, February 24, 2004 - 1:55 pm: |
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FM IS NOT ILLEGAL ON CB JUST ON 26-27 MHZ CB?
MY HR 2510 HAS FM AND I USE IT ON 27 MHZ. I WOULD JUST DO WHAT YOU WANT TO DO.
FREEEEEEEEEEEEEEEE-BANDEEEEEEEEEEER |
Bruce
Senior Member
Username: Bruce
Post Number: 1016
Registered: 9-2003
| | Posted on Tuesday, February 24, 2004 - 2:48 pm: |
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Freebander
Your hr-2510 is also illeagal |
Johnhenre
Junior Member
Username: Johnhenre
Post Number: 36
Registered: 1-2004
| | Posted on Tuesday, February 24, 2004 - 4:59 pm: |
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BRUCE CAN MY GALAXY DX 44V FM BE CHANGED TO A FREQ. OF 30.760 MHZ.? BOB |
Bruce
Senior Member
Username: Bruce
Post Number: 1019
Registered: 9-2003
| | Posted on Tuesday, February 24, 2004 - 8:09 pm: |
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Bob
Im not shure what your tring to do with it can it be channeled out to 30.760? i would think so but WHY? and who would you talk too? also above 30 MHZ it would require FCC aproval. The rules are not the same as at 27. |
