[Elecraft] New beta K3 firmware!

[Joe Subich, W4TV]

 > This in-band noise "pedestal" could be 20-30 dB above the normal
 > transmit noise floor if you were using a lot of mic gain and/or
 > compression. If you were using high power in these modes, your signal
 > would now be much more likely to bring up the receive noise floor at
 > nearby stations.

It would seem that the same argument would be made against using the
2.7 or 2.8 KHz filters for CW or digital modes that have a transmit
bandwidth of 50 to 100 Hz.  Why generate an excessively wide 3 KHz noise 
pedestal for CW or PSK31/63 or even FSK RTTY (300 Hz required)?

This is all academic since it is easy - although very inconvenient - to
set FL1 BW to 6.00 with the FM filter to enable AM/ESSB and return it
to 13.00 to go back to FM.

The real issue is that any user with three "narrow" filters for SSB and
CW/Digital is precluded from using both FM and AM/ESSB without playing
games with FL1 BW.

73,

    ... Joe, W4TV


On 9/21/2012 6:40 PM, Wayne Burdick wrote:
> The 6 kHz filter band-limits the transmit noise originating from the
> DAC and the transmit mixer to a bandwidth appropriate for AM and ESSB
> modes. The 15 kHz filter would allow a noise bandwidth over twice as
> wide.
>
> This in-band noise "pedestal" could be 20-30 dB above the normal
> transmit noise floor if you were using a lot of mic gain and/or
> compression. If you were using high power in these modes, your signal
> would now be much more likely to bring up the receive noise floor at
> nearby stations.
>
> Do you really want to create a 15-kHz wide swath of broadband noise
> when using ESSB or AM?
>
> I don't. That's why I haven't modified the code to allow use of the FM
> filter for this purpose. I suppose it could be YAMU (yet another menu
> entry), forcing you to do at least a minimum amount of soul-searching
> before "going broadband" :)
>
> 73,
> Wayne
> N6KR
>
>
> On Sep 21, 2012, at 3:09 PM, Thomas Horsten wrote:
>
>> Hi Gary,
>>
>> The point is not to widen the SSB but to use the FM crystal filter
>> to limit
>> it. The DSP does the actual shaping of the TX signal which will
>> still be
>> the same width regardless of whether you're using the 6kHz filter or
>> the
>> 12.5kHz FM one.
>>
>> The idea is to be able to use the FM filter for AM and ESSB as well
>> instead
>> of filling up two precious filter slots, when what you may want/need
>> are
>> closer filters on the low end (say, 400 and 200 Hz).
>>
>> 73, Thomas M0TRN
>>
>> On 21 September 2012 22:00, Gary Gregory <garyvk4fd at gmail.com> wrote:
>>
>>> Joe,
>>>
>>> I have to ask, why?
>>>
>>> In VK we have a 3Khz SSB BW written into our LCD's and yet some folks
>>> consume 10Khz out here on a net which tears up a considerable
>>> amount of
>>> spectrum.
>>>
>>> What advantage do you see to widen the ESSB?
>>>
>>> Not sure I follow your thoughts here, hence the question Joe.
>>>
>>> 73
>>>
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