[Elecraft] New beta K3 firmware!

[Wayne Burdick]

Maybe I'll put the feature in and let you be my guinea pig, Joe. One  
complaint about noise bandwidth and it comes back out ;)

Wayne


On Sep 21, 2012, at 4:20 PM, Joe Subich, W4TV wrote:

>
>> 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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