[Elecraft] Why ESSB and AM?

[Joe Subich, W4TV]

 > ESSB might be useful to transmit a wide-band, high bit rate
 > digital mode via a computer sound card. Those sound cards have
 > at least 15KHz bandwidth,

ESSB is limited to 4.0 KHz but is not available in digital modes
(DATA A or AFSK A).  While ESSB might be useful for those modes in
which "panoramic" (click in a 2.5 to 3 KHz wide waterfall) operation
is the norm, nearly every transmitter has an "in band" noise pedestal
(broadband noise) the width of the transmit filter that is only 60
to 80 dB below the transmitter's PEP output.

By the way, in the K3 when the ALC is adjusted for 4-5 bars and the
PWR control reduced to 25 watts or so for PSK31, that noise pedestal
is 80 dB relative to 25 watts  In the conventional rigs where the
power control is run "wide open" and the audio drive (mic gain) set
for no ALC, that noise pedestal is 60 to 80 dB below the *FULL POWER*
level as the IF stages run wide open providing maximum amplification
of the broadband noise.

73,

    ... Joe, W4TV


On 9/23/2012 2:13 AM, Bill Frantz wrote:
> When Don wrote the paragraph quoted below, I started to think
> why I would want to use one of these modes. AM doesn't seem very
> likely except as a demo.
>
> But ESSB might be useful to transmit a wide-band, high bit rate
> digital mode via a computer sound card. Those sound cards have
> at least 15KHz bandwidth, which would need to be reflected in
> the transmitter (and receiver) bandwidths. That amount of
> spectrum would be reasonable in bands where FM is commonly used.
>
> I find the regulations for 160M-10M confusing as to the maximum
> bit rate* and bandwidth permitted, but on 6 meters, the
> authorized bandwidth is up to 20 kHz with a maximum baud rate of
> 19.2K baud/second.
>
> Cheers - Bill, AE6JV
>
> * The regulations speak in terms of maximum baud rate, but you
> can send more than one bit/baud, if you have enough bandwidth.
>
> On 9/22/12 at 18:19, w3fpr at embarqmail.com (Don Wilhelm) wrote:
>
>> I too would like to see the FM filter also usable for AM and
>> ESSB. I really never anticipate transmitting in AM or ESSB,
>> there is always the possibility I would like to use it for some
>> demo sessions showing off the K3 capabilities.  The
>> cost/benefit ratio is too high for that kind of occasional application.
>
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> Bill Frantz        |"Web security is like medicine - trying to
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> 408-356-8506       |an evolved body of kludges" - Mark Miller
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