| Author |
Message |
    
Graymatter
New member
Username: Graymatter
Post Number: 2
Registered: 11-2004
| | Posted on Sunday, April 23, 2006 - 9:46 am: | 
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I recently converted a new Kenwood ts2000 radio using the mod found on the web, and have been very happy with the results. I use a Heil Goldline Pro mic, which effectively fixes the "low level" modulation many AM'ers are concerned about. It has a built in antenna tuner, DSP, VOX, and a number of "soft" mods you can do. There is a special maintenance menu you can use to peak and tune the radio without opening it up (200 w. ssb). On SSB, the radio is second to none. Total cost was $1700 for mic and radio. |
Hollowpoint445
Senior Member
Username: Hollowpoint445
Post Number: 1194
Registered: 6-2004
| | Posted on Sunday, April 23, 2006 - 11:32 am: |
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"Low level" modulation refers to the design of the radio. It means that modulation is added to RF at a low power level early in the RF stage, and then the modulated RF is linearly amplified to the final output power level.
High level modulation is where modulation is actually added at higher RF power levels later in the RF output stage. It requires more audio amplification/power, which can make it a little easier to control.
It's possible to have a great AM signal with low level modulation if the user takes the time to properly adjust the radio controls. You can't just crank the microphone level, scream into the microphone, and have great AM with low level modulation. It usually takes conservative adjustment of the carrier level, along with using the speech processor and microphone gain judiciously to get the proper level of modulation. Using the ALC function of the radio's meter is the only way to really know if you've done a good job. |
Bruce
Senior Member
Username: Bruce
Post Number: 3773
Registered: 9-2003
| | Posted on Saturday, April 29, 2006 - 8:07 pm: |
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I have had a bunch of radios over 40+ years including collins, Haillcrafters, Hamerland, Regency and drake ( R4-b, T4xb station 1970 ) before any Icom ever came along.
My first ICOM was a IC-230 in 1974 first Yeasu was a FT-620 in 76 and Kenwood TS-700 in 76 so i have had a lot more that ICOMS.
He has a problem ........The 706 is a FINE SOUNDING RADIO even on 440 mhz If his sound that bad he needs to SEND IT BACK. Mine is used on fm/ssb all the time and i work nets on 6, 2 and 440 with it and i have even run contest on SSB up on 440 mhz with it no problem.
I run ICOM, Yaesu, Alinco and even the kenwoods and the IC706mk2g with a heil mike sounds as good as anything out there.
I had a ts2000 here that a local had bought and put it side by side with the 706 and FT-100 and did not find it any better on receive on 20 meters.
We fired it up on 20 the person in Texas found no diffrence between the FT-840 - md-100 mike ( my main hf station ) and the ts-2000 on transmit.
Im not keen on Yeasu high end radios either.
Now the IC-7000 is impressive but like i said dosn't give me anything i dont already have.... |
Bruce
Senior Member
Username: Bruce
Post Number: 3775
Registered: 9-2003
| | Posted on Saturday, April 29, 2006 - 9:45 pm: |
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The rule is about 3KHZ MAX for a SSB signal and some of these " HIFI SSB " radios go 6KHZ. The advantage of SSB is with redused bandwidth you can get weaker signals and place more of them into a given space allowing 6 khz defeats this and has no advantage over AM. |
Hollowpoint445
Senior Member
Username: Hollowpoint445
Post Number: 1203
Registered: 6-2004
| | Posted on Sunday, April 30, 2006 - 1:42 pm: |
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I understand why they want to be allowed to use a similar bandwidth as AM, but I don't think their arguments are valid. 3kHz is plenty of bandwidth for speech intelligibility, the rest is higher frequency speech that adds little to intelligibility for the average person. Perhaps women and children could realize slightly more intelligibility because of their higher pitched voices, but I've never had a problem understanding either on normal bandwidth SSB.
Back in the mid '90s when I got started in CB, the "techs" who worked on radios claimed that they clipped limiters because the audio was better when the microphone was set properly - not necessarily louder. Of course no one (including those techs) had station monitors to actually watch the wave form to make that adjustment properly, so they all splattered at least two channels in either direction. To me the Hi-Fi SSB crowd is using the same kind of faulty logic. They're breaking the rules in name of better audio when that's not what amateur radio is about. It's about communication, not high fidelity.
About SSB - I like SSB for it's efficiency and generally much better filtering over AM - especially in CBs. For the same PEP you can communicate much further. I've seen it explained that a 12 watt PEP SSB transmission is similar to a 100 watt PEP AM transmission when you consider the additional filtering and narrower bandwidth of the receiver. There is a 9dB advantage for SSB over AM. As a mode it's superior to AM. |
Bruce
Senior Member
Username: Bruce
Post Number: 3777
Registered: 9-2003
| | Posted on Sunday, April 30, 2006 - 5:49 pm: |
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And that 9 DB is because you have LESS BANDWIDTH !
The laws of recever noise floors is this the noise floor is dependent on 2 main things .....
1) BANDWIDTH
2) Frount end noise figure
NOISE FLOOR = -174 + ( NOISE FIGURE ) + 10log10 (BANDWIDTH ) + 10
So if you INCREASE bandwidth your noise floor gets worse and you can't receive thoes week signals. |
Hollowpoint445
Senior Member
Username: Hollowpoint445
Post Number: 1204
Registered: 6-2004
| | Posted on Sunday, April 30, 2006 - 7:12 pm: |
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Wouldn't just 3dB come from the reduced bandwidth? |
Bruce
Senior Member
Username: Bruce
Post Number: 3779
Registered: 9-2003
| | Posted on Sunday, April 30, 2006 - 7:17 pm: |
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I would think so your right ...... but remember 75% of power in a am signal is wasted and that is the extra 6 db
In any case there is no advantage in a 6 khz wide signal .. |
Graymatter
New member
Username: Graymatter
Post Number: 5
Registered: 11-2004
| | Posted on Wednesday, May 03, 2006 - 5:55 pm: |
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You guys are over analizing this. I am using ESSB on 11 meters. I run a 3.4 kc signal with EQ'ing. It is a marked improvement on Ancient Mary.
73's |
Kid_vicious
Senior Member
Username: Kid_vicious
Post Number: 1506
Registered: 9-2004
| | Posted on Wednesday, May 03, 2006 - 7:31 pm: |
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they are just having fun.
sometimes we dont know what we want to discuss until we are in the midst of it.
matt |
Graymatter
New member
Username: Graymatter
Post Number: 7
Registered: 11-2004
| | Posted on Friday, May 05, 2006 - 4:53 pm: |
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I made this post for the benefit of my fellow CB'ers. Anybody with a little money and savvy can have a nice radio for CB. |
Tech808
Moderator
Username: Tech808
Post Number: 9919
Registered: 8-2002
| | Posted on Friday, May 05, 2006 - 6:43 pm: |
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Moderator Note!
I have edited and deleted several of the posts above.
PLEASE address/post your comment's to the QUESTION/TOPIC: Converting Ham to CB
NOT to an individual who is also posting his or her comments.
The Question/Topic has nothing to do with the legality of doing the modification or to become a debate od radio brands/model's.
If you wish to discuss the legalities or brand's or model's of radio's then PLEASE start a new topic.
Thank's,
Lon
Tech808
CEF808
N9CEF
CVC#2 |
