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Message |
    
Maxgain
Junior Member
Username: Maxgain
Post Number: 34
Registered: 3-2007
| | Posted on Wednesday, August 29, 2007 - 9:37 pm: | 
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I have noticed over the years some guys running solid state, (yeasu,kenwood,icom), ham rigs on the CB channels and they try to get the ham rig to produce "loud" AM tx audio and they never seem to quite get it.
It seems that a basic tweaked CB or "export" is the way to go for LOUD AM transmit audio.
Why is this?
You would think that for being as expensive as they are a solid state ham rig would have superior desighn in it's favor but there's something missing. The CB/export group always seem to be noticably louder .
What's going on here? |
Unit199
Advanced Member
Username: Unit199
Post Number: 533
Registered: 8-2003
| | Posted on Thursday, August 30, 2007 - 5:14 am: |
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The main reason is that a ham radio is designed for the quality of audio not the loudness and ham radios are not designed for the 11 meter band and especially AM MODE!!!
HARVE
UNIT199
CEF210
CVC#18
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Dale
Senior Member
Username: Dale
Post Number: 1113
Registered: 12-2002
| | Posted on Thursday, August 30, 2007 - 5:32 am: |
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yup exactly right.ham radios are surpirior
to any 11meter or export radio on ssb.they
werent really designed with am in mind.if ya
notice the older tude ham radios dont even
have am mode all ssb
dale/a.k.a.hotrod
cef426
cvc#64
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Mister455
Junior Member
Username: Mister455
Post Number: 12
Registered: 12-2004
| | Posted on Thursday, August 30, 2007 - 9:52 am: |
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Some older ham radios naturally sound nice on AM Mode, as do most older Tube CB rigs.
Newer HAM radios can get good audio, but usually it envolves pretty extensive stuff to get the audio up to snuff.
I prefer a good clean, easy to copy signal; regardless ofthe mode being used. |
Hotwire
Senior Member
Username: Hotwire
Post Number: 2383
Registered: 1-2005
| | Posted on Thursday, August 30, 2007 - 1:07 pm: |
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I agree, loud and proud AM audio is not put on the drawing board when designing a top of the line Icom Kenwood or Yaesu!
Man if you ever have heard a great working ic-7800 or ts-2000 on usb you would fall in love! To this day I have not forgotten the ssb audio coming from Chile. The operator was using one of the newer base Kenwoods and it was just magnificent how nice he sounded!
KEEP IT REAL!
Kenny
cef491(27.115lsb)
2sf491(27.555usb)
Indiana
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Maxgain
Junior Member
Username: Maxgain
Post Number: 35
Registered: 3-2007
| | Posted on Thursday, August 30, 2007 - 6:18 pm: |
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I guess I'm looking for a technical reason that solid state ham rigs can't get "loud" on AM and CB's can.
What is essentially different in the AM tx circuits? |
Marconi
Advanced Member
Username: Marconi
Post Number: 749
Registered: 11-2001
| | Posted on Thursday, August 30, 2007 - 9:19 pm: |
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I am not technical at all in the area of the radio, but I would suspect that the quality you ask about is derived by how the drive of the transistors are set. If you have a power transistor capable of 8 watts and you drive it with a 5 watt driver transistor, the audio is likely to be under better control as to quality than it would be if the driver dead key is set to only 1 watt and driving out to the 8 watts max. |
Bruce
Senior Member
Username: Bruce
Post Number: 4499
Registered: 9-2003
| | Posted on Friday, August 31, 2007 - 5:28 pm: |
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MAXGAIN ....
The reason is simple who uses AM any more?
Most radios are low level derived AM unlike the collector modulated high level AM most CB radios have.
That said I have no problems with AM either on 10 or 75 meters using my FT-840 .....
On 6 since 66
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Hotwire
Senior Member
Username: Hotwire
Post Number: 2390
Registered: 1-2005
| | Posted on Tuesday, September 04, 2007 - 12:21 pm: |
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I'm not sure exactly the AM componet differences in a cb and a ham radio.All the loud and proud AM mode reeks havoc on the band with splattering bleedover. Tune to the high end of 10 meters when the skip is strong and you will hear cb there. You can even hear your local nieghborhood splatterbox up there sometimes if your close enough.The number 1 thing that annoys me is AM splatter when I'm trying to work another country on SSB! A problem that will never go away on 11 meters but in the ham community it is not tolerated and it shows in the radio design!
It is just that big loud and proud AM audio is unneccasary and causes problems in the band and the last thing a ham wants is his radio to be operating in an unacceptable manner before his peers.
I don't need to be speaker busting loud to have a world class station.
KEEP IT REAL!
Kenny
cef491(27.115lsb)
2sf491(27.555usb)
Indiana
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Patzerozero
Senior Member
Username: Patzerozero
Post Number: 3920
Registered: 7-2004
| | Posted on Tuesday, September 04, 2007 - 6:43 pm: |
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to continue on bruce's statement, many HF rigs don't use true AM either, but they inject a carrier into one of the sidebands. the end result, when CBers try to use hf rigs on 11 meter AM, they turn things up too high and sound like they are on SSB rather then AM. they want to see the 'meter swing', however, reading the owners manual ALWAYS says the ALC meter should see MINIMAL movement, and certainly not past a certain point. set things up that way, yeah, you may not even see the output of an export radio, BUT, 15-20 watts carrier, and 60 or more PEP on AM, with a decent amplified microphone set correctly and you WILL have AM audio that demands respect. |
Pickj
New member
Username: Pickj
Post Number: 3
Registered: 12-2008
| | Posted on Sunday, December 14, 2008 - 9:42 pm: |
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AM modulation is a thing of the past, on ham radio. I can tell you from experience that any AM radio that has high level AM modulation will be MUCH LOUDER than a low level AM modulated unit. The difference is, high level modulation is achieved when the RF signal is modulated by the audio amplifier in the FINAL RF stage of the radio. This is far louder and superior in quality. Low level modulation is where a low level audio signal is modulated with the RF signal several stages before the final amplifier. Many of the older CB rigs are high level units unlike most units of today. Low level modulated units are cheaper to build. A majority of the older CB radios were modulated with a audio signal that was close to 5 watts of power (TA7205P chip) You won't find that today. |
Captian_radio
Intermediate Member
Username: Captian_radio
Post Number: 490
Registered: 9-2004
| | Posted on Monday, December 15, 2008 - 8:33 am: |
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If you want good AM from a ham rig get an oldie like a Johnson Ranger etc I have an old Johnson all tube transmitter (Pacemaker) with AM and SSB and although not a big power house it is sparkling on AM.
Years ago there was a ham from I believe Maine that used only AM gear on 80 meters and man what a great sounding station.I remember him saying that he had ice on his antenna and he would fire up the amp and say oh yeah the ice is melting now .His shack burned down years ago (must have been too much RF lol)and I haven't heard him since.Those of you who go back that far will know who I am talking about.
Bob
Robert L. Spicer The days of radio are just beginning!
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