[CQ-Contest] Mission Impossible

[bogus at does.not.exist.com]

This tread is going on on the amps reflector but it really
belongs here

de SM2EKM
-----------------------------------------------


      Yes I agree Tom. But in spite of the known exciter problems
       it is possible to run the radios so they sound pritty good
       and have quite decent bandwith.
       When I first got the FT1000D I started to run it like this,
       ALC wiggling around the top of the blue scale and compression
       15 - 20 dB. Everybode I asked told me it sounded good or
       OK and nobody complained about the bandwith. Few years
       later after som testing with a friend (SM2CEW wrote about
       this in a previous post) we realized it was totaly wrong to
       run it like that. If you run the ALC level that high the signal
       level will increase almost 10 dB 3.5 kHz away, don´t know 
       how much larger the total bandwith will get but we can all
       agree on that it will get considerably larger. Now I run the
       radio so that the ALC meter just comes up a slight bit on the
       blue scale and I try to get the peeks on the compression meter
       not to exceed 10 dB. 
       This is an example from findings in reel life, no tecnocrate 
       measurements but pure simple dirty real life findings. In this
       case I have proved that it´s possible to run the FT1000D so
       it an excessive bandwith without really sounding bad. To get to
       the playground with those wide prominent contest hall of fame
       contesters it seems to me I would have had to increase ALC level
       even further and compression to 50 dB or so to be even close.
       What I ask myself is what is the explanation? Is it on dead 
serious
       purpose these guys are doing this or are the simply ignorant or
       do they simply not understand.
       I must give you a few examples. K1AR sounded so bad on all bands'
       I simply had to tell him about it on one band, ofcourse he showed
       total ignorance.
       K3LR sounded so bad on 15m that I had to ask him if he bought 
the 
       radio at K-MART, he claimed he didn´t so I asked him what he was
       running, it was a IC-781 and it sure beats me how a 781 can sound
       that band and also have that tremendous bandwith.
       W3BGN I tried to tell on 20m, he had a lot of distortion an very 
wide
       signal, all he did was BSing me with that he turned on his scope 
and
       sure enough his signal looked OK.
       KB1H sounded so bad on 10m when he called me so I got so pissed
       off that I refused to work him.
       Oh yes, KC1XX sounded reel bad on many bands as W3LPL did but
       I never botherd to tell them anything. There are also other 
examples
       but I didn´t keep notes so this is all I remember.
       I tell you guys, there used to be a time when USA stations 
sounded
       nice and they had nice behaviour but these days I simply don´t 
know
       what´s going on.
       So you tell me am I totaly wrong, am I stupid or what? Sometimes 
I
       think I´m dreaming so I have to pinch my ear to check!!

       73 from a frustrated SM2EKM
------------------------------------------------------------

-----Ursprungligt meddelande-----
Från:	w8ji at contesting.com [SMTP:w8ji at contesting.com]
Skickat:	 den 6 mars 2000 13:22
Till:	w8ji at contesting.com; amps at contesting.com; Jan.E.Holm at telia.se
Ämne:	Re: [AMPS] Re: Mission Impossible

>      Good somebofy did bring this up. At first I couldn´t beleive
>      what was going on and had to call a coupple of friends to
>      check if they did see the same, it was abslutley dreadful.
>      I tried to tell a few but ofcourse nobody wanted to take
>      notice. Many many big prominent stations did sound just
>      awful with big distortion and ecessive bandwith, if you
>      like I could name a bunch of callsigns but I don´t think
>      those guys read this reflector, maybe the contest one.
>      de Jim SM2EKM

If you think 40 and 20 meters are problems, try operating 160 
meters from a quiet location one hop away from some newer rigs.

On SSB most exciters are far worse than the PA's assuming the 
PA is properly tuned.

For all the complaints about PA's, look at IMD specs for many 
transceivers. Many of them not only have poor IMD that extends 
out very far, but they also have a large leading edge overshoot 
because of slow ALC response.

Until the exciters are corrected, the problem will remain.
73, Tom W8JI
w8ji at contesting.com
 <<Fil: Re_ [AMPS] Re_ Mission Impossible.TXT>> 



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