W8JI article about eSSB & all that

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YO3IBW
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W8JI article about eSSB & all that

Post by YO3IBW » Mon Dec 13, 2010 5:06 am

What do you think about this article? If I understood correctly, W8JI was one of those who complain to FCC to create a law that will make eSSB illegal.
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Post by Voodoo Guru » Mon Dec 13, 2010 8:57 am

Howdy YO3IBW,

Were not sure if he was one of the original complainers who sent the petition to the FCC or not, but that is ancient history as the FCC denied their petition and has given us the green light for this type of experimentation.

First we must say that it is up to the eSSB enthusiast to be aware of his Bandwidth and practice Good Amateur Practices. By this we mean to look up and down the band before we start to transmit to make sure that no one is in our pass band. This would be akin to looking both ways before you cross the street. If there is someone up or down the band, then you need to adjust your bandwidth accordingly.

If on the other hand, someone starts transmitting in your pass band after you were there first, then they are totally in the wrong and are not showing proper courtesy to you and are definitely not presenting Good Amateur Practices.

It would behoove you to read these articles penned by John, NU9N:

http://www.nu9n.com/apologetics.html#eSSB_perceptions

http://www.nu9n.com/apologetics_2.html


As far as the W8JI article you mentioned is concerned, for the most part what he is saying is true and the math is correct, but from the tests we have made here, he is exaggerating a bit on the final effect. As compared to a properly balanced Audio chain into a good transmitter and correctly tuned amp, there are far more contesting stations and poorly tuned amps out there that are causing far more IMD then any eSSB station ever thought about creating.

We have tested the IMD on many (10+) TS-950sdx transceivers with both the 2 Tone and the 3 Tone tests that he described in his article. This is in fact standard procedure here.

- All Testing are accomplished with a Tektronix 2712 Spectrum Analyzer.
- Transmitter is at Full Power (150 watts PEP) with minimum ALC.
- 2 Tone Tests were performed with 500cps and 3000cps.
- 3 Tone Tests were performed using 500cps & 3000cps tones, with a 3rd tone ranging from 60 to 150cps in a 1 second bi-directional sweep & modulated @ 100% with a period time of ½ second

The results between the 2 Tone and the 3 Tone tests were that the 3 Tone test consistently showed an average of only -2dB worse on both the IM3 & IM5 products.

Granted that the TS-950sdx is probably the best & cleanest rig out there for use with eSSB due to its 50V Mosfet Finals. These finals are only running at half there rated output which gives them lots of headroom. Much more then a PA using 12V finals.

Still, even the TS-870, which he mentioned in the article, if it is ran at only 50 watts to drive a high gain power amplifier has IMD products that are acceptable. It is however a different story when you raise the output level up to 100 watts, as the IMD on the TS-870 is quite poor at full output.

The bottom line is this,
You have to be responsible for your Bandwidth, just as every other Amateur Operator is. More so in fact because we are targets. Always be courteous until you can't.

Take Care,
Last edited by Voodoo Guru on Mon Dec 13, 2010 3:34 pm, edited 1 time in total.
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Post by YO3IBW » Mon Dec 13, 2010 1:37 pm

Howdy Voodoo Guru!
Yes, I perfectly agree with you on this mater. I do consider that W8JI is a bit exaggerated with his article. A bad setup adjustment of the entire station can cause problems no matter the bandwidth used on the transmission.
As a friend of mine was saying " I do prefer any time an eSSB transmission than a station using a class C amplifier with a double side band with almost suppressed carrier" . The European forum members understand better the phenomenon coming from the east, specially on the low bands (80m / 160m).

:roll:
73 de Dan YO3IBW
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Post by !KANT » Sat Jan 08, 2011 4:38 pm

It's always interesting to see/read/hear those whom are technically incline such as W8JI who can prove or fight so sizablly against this practice. It makes me want to question with, "how would you IMPROVE these transceivers or components used to provide a higher standard of performance which would be ACCEPTABLE??"

The reason I say this is because, anyone who can go through this bladle to show something is "incorrect" should be able to offer a sound "solution" (other than, "JUST DON'T DO IT!!"

[See those kids playing baseball in the street?? They can get injured by oncoming traffic. Tell them to stop PLAYING in the street, show them gruesome photos horrific car accidents involving pedestrians, call their careless parents!!!... Or just guide them to the playground after you're done with your Shytography]… :wink:

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