SV: SV: SV: [AMPS] Mission Impossible

[sm5ki]

----------
>Från: "sm5ki" <sm5ki@algonet.se>
>Till: sm5ki <sm5ki@algonet.se> , Peter Sundberg <sm2cew@telia.com> ,
measures <2@vc.net>
>Kopia: amps@contesting.com
>Ämne: SV: SV: [AMPS] Mission Impossible
>Datum: mån 6 mar 2000 19.39
>

>
>----------
>>FrÂn: "sm5ki" <sm5ki@algonet.se>
>>Till: Peter Sundberg <sm2cew@telia.com> , measures <2@vc.net>
>>Kopia: amps@contesting.com
>>Ÿmne: SV: [AMPS] Mission Impossible
>>Datum: mÂn 6 mar 2000 19.31
>>
>
>>Hej Peter:
>>
>>In the TS950 two-tone test in QST 1/1991 distorsion is abt 42 dB below pep
>>for 3rd order mods. Higher order mods are also very low. This was worst case
>>measurment and on most bands it should be even better. However, I cant see
>>how much ALC was used in this test? Maybe no ALC? This rig usually sounds
>>very clean.
>>
>>I think the problem is behind the microphone as 150 watts pep is avaiable
>>and there is a possibility that too much drive was used for the finals. One
>>has also to know how the ALC from the amp was connected and used etc. Did
>>they use clipping and did they know how to use it properly? Maybe talked to
>>close to the microphone which in some differential pressure electret
>>microphones leads to distorsion. Do you remember when the ICOM SM2 first
>>came out? Boerge who worked for Bruel/Kjaer quickly found out, you could not
>>talk close to that microphone without getting very bad speech quality. This
>>has of course nothing to do with splatter outside the passband.
>>
>>Hej daa de Hans
>>
>>
>>----------
>>>Fr¬n: Peter Sundberg <sm2cew@telia.com>
>>>Till: measures <2@vc.net>
>>>Kopia: amps@contesting.com
>>>ümne: RE: [AMPS] Mission Impossible
>>>Datum: m¬n 6 mar 2000 17.13
>>>
>>
>>>
>>>At 07:55 2000-03-06 -0700, Rich wrote:
>>>>>Checking the web pages out shows these stations run FT1000MP's, FT1000D's,
>>>>>TS-950's, Alpha's, Henry's, you name it.
>>>>>
>>>>Peter -  'This has got to be an amplifier adjustment problem.  The radios
>>>>you mentioned are fairly clean.
>>>>
>>>>cheers.
>>>
>>>This is what puzzles me, but there is no doubt that "fine" radios can turn
>>>into mean machines if they are improperly adjusted. Many of the signals
>>>heard over the weekend had the sound to them that you get from setting the
>>>bias too low. I suppose this could be in either the exciter or the
>>>amplifier but it must be the easiest thing to check for most amateurs. Then
>>>again, one would have to find out what the ZSAC should be..
>>>
>>>I have been making some test with a good friend of mine re the behaviour of
>>>the FT1000D when driven beyond the ALC top level. IMD products 3.5 kc away
>>>from from the ssb carrier frequency rises about 10 db just by letting the
>>>ALC needle swing a little higher than recommended. This test turned out
>>>equal on two FT1000D's, driving different types of amplifiers. There is no
>>>doubt that even the FT1000D needs full attention not to sound bad.
>>>
>>>Listening to the microphone freaks on 14178.00000 in the mornings will tell
>>>you that the TS950SDX will splatter, check "Your Friend's" signal out and
>>>you will hear quite a lot of hash down the band. And they think they have
>>>the best audio achievable on SSB. Well they might (if you like the sound
>>>and want to spend 10.000 USD on a mixer/microphone), but out of the
>>>passband there is trash. Trash that their friends who want to operate close
>>>to the frequency will have to listen for NO reason.
>>>
>>>So Rich, it could be the amps, it could be the transmitter, but I'd go as
>>>far as to say it is the transmitter that makes the signal sound bad in most
>>>cases. (Or should we say the combination, to be politically correct..)
>>>
>>>Ciao,
>>>
>>>Peter/SM2CEW
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>--
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>>>Problems:                 owner-amps@contesting.com
>>>Search:                   http://www.contesting.com/km9p/search.htm
>>>
>>>

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