Message-ID: <503FB292.8070507@freenet.de>
Date: Thu, 30 Aug 2012 20:36:02 +0200
From: wolf_dl4yhf <dl4yhf@freenet.de>
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To: rsgb_lf_group@blacksheep.org
References: <503EA718.2010301@charter.net>,<8CF54D89088EA63-22E8-50D77@webmail-d136.sysops.aol.com> <BLU153-W389FBFD780562FED0790B6CFA70@phx.gbl>,<B7E13557053D429E8C6F45855FE409D8@AGB> <BLU153-W10946B7505ACF6155BE9C1CFA70@phx.gbl>
In-Reply-To: <BLU153-W10946B7505ACF6155BE9C1CFA70@phx.gbl>
Subject: Re: LF: : Opera frequency usage and clicks, and over the Pole
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Hi Laurence and all,

Am 30.08.2012 19:18, schrieb Laurence KL7UK:
> Thanks G  I can/could go comm port keying but prefer the audio being 
> lazy.-
>
>  it appears in my set up that the rise time is very short and less 
> than the 5mSec thats generally accepted as required hence the click - 
> but Im sure Im seeing more than just the first rise of the sine, Ill 
> do some more delving -  but Im sure the software could be make more 
> soft with a slower ramp as done on Markus' Chirpix and some of the PSK 
> programs - It appears to be an anomoly with only Opera here? Am I alone?
Certainly not. I was also a bit annoyed by keying clicks (not only from 
Opera though).

A smooth ramp wouldn't cost much, and certainly will not affect the 
'average power' since there are not so many on/off transitions. From the 
software side, this should be extremely easy to implement (for "audio 
driven" linear transmitters).

The problem may be for people with hard-keyed ("brutally on/off keyed") 
transmitters, where the driving circuit may play havoc when fed with low 
input amplitudes.
But imho, for someone capable of building a large antenna, a large 
amplifier, etc etc, it shouldn't be too difficult to provide an adequate 
keying circuit either by modulating the DC supply voltage or similar means.

"A simple on/off keyed CW transmitter" without envelope shaping may be 
ok for QRP experiments but not for QRO on a crowded (?) band. This 
applies to LF, MF, and HF. Almost as bad (but often seen on 40 meters): 
Transmitter putting out a nicely shaped amplitude ramp, but a terrible 
power amplifier, completely overdriven, which completely removes the 
amplitude ramp or shortens it to fractions of a millisecond (i.e. 
clicking "bandwidth" in excess of one kHz).


All the best,
    Wolf  DL4YHF .


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    <div class="moz-cite-prefix">Hi Laurence and all,<br>
      <br>
      Am 30.08.2012 19:18, schrieb Laurence KL7UK:<br>
    </div>
    <blockquote cite="mid:BLU153-W10946B7505ACF6155BE9C1CFA70@phx.gbl"
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      <div dir="ltr">
        Thanks G&nbsp; I can/could go comm port keying but prefer the audio
        being lazy.-<br>
        &nbsp;<br>
        &nbsp;it appears in my set up that&nbsp;the rise time is very short and
        less than the 5mSec thats generally accepted as required hence
        the click - but Im sure Im seeing more than just the first rise
        of the sine,&nbsp;Ill do some more delving&nbsp;- &nbsp;but Im sure the
        software&nbsp;could be&nbsp;make more soft with a slower ramp as done on
        Markus' Chirpix and some of the PSK programs - It appears to be
        an anomoly with only Opera here? Am I alone?<br>
      </div>
    </blockquote>
    Certainly not. I was also a bit annoyed by keying clicks (not only
    from Opera though).<br>
    <br>
    A smooth ramp wouldn't cost much, and certainly will not affect the
    'average power' since there are not so many on/off transitions. From
    the software side, this should be extremely easy to implement (for
    "audio driven" linear transmitters).<br>
    <br>
    The problem may be for people with hard-keyed ("brutally on/off
    keyed") transmitters, where the driving circuit may play havoc when
    fed with low input amplitudes. <br>
    But imho, for someone capable of building a large antenna, a large
    amplifier, etc etc, it shouldn't be too difficult to provide an
    adequate keying circuit either by modulating the DC supply voltage
    or similar means.<br>
    <br>
    "A simple on/off keyed CW transmitter" without envelope shaping may
    be ok for QRP experiments but not for QRO on a crowded (?) band.
    This applies to LF, MF, and HF. Almost as bad (but often seen on 40
    meters): Transmitter putting out a nicely shaped amplitude ramp, but
    a terrible power amplifier, completely overdriven, which completely
    removes the amplitude ramp or shortens it to fractions of a
    millisecond (i.e. clicking "bandwidth" in excess of one kHz).<br>
    <br>
    <br>
    All the best,<br>
    &nbsp;&nbsp; Wolf&nbsp; DL4YHF .<br>
    <br>
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