Elecraft

K3s transmit bandwidth adjustment?

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Michael Blake

K3s transmit bandwidth adjustment?

Using normal SSB with the stock 2.7kHz. wide crystal filter is there any way to adjust the lower and upper bandwidth frequency ranges other than the TX EQ?

For example how would I adjust so that my 2.7 kHz. bandwidth was from 200Hz. to 2900Hz.?

It is easy to do on the receiver but I cannot figure out how to do this on the transmitter.

73 - Mike - K9JRI

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Bob McGraw - K4TAX

Re: K3s transmit bandwidth adjustment?

Based on my measurements the transmit frequency response is limited by
the 2.7 kHz SSB filter. It is reasonably flat thus +/-3 dB from 400 Hz
to about 2500 Hz. My next measurement points were 300 Hz {-6 dB} on the
low end and 3000 Hz {-6 dB} on the high end or 2700 Hz.

Thus your numbers of 200 Hz to 2900 Hz is 2.7 kHz, otherwise about the 6
dB points on the filter. I did not go into the ESSB mode and perform
any measurements. These were done in DATA mode, thus negating TX EQ
and Speech Processing. I also did similar measurement with TX ALC OFF
and in USB mode and in USB with TX EQ set to 0 dB at all frequencies and
well below any ALC action.

While I'm always reluctant to measure and report transmit frequency
response of a SSB transmit path, namely because many users not
understanding what takes place, thus would exclaim "that's horrible
frequency response" while in fact just the opposite is true in that it
makes for darn good sounding audio.

To answer your question, referring to the Elecraft manual and the Fred
Cady book, I find no way to "adjust" the transmit frequency response
other than via the TX EQ. On that point, I will emphatically state "it
is always better to attenuate a frequency or range of frequencies as
opposed to boost a frequency or range of frequencies".

73

Bob, K4TAX

On 2/10/2018 12:04 PM, Michael Blake wrote:

> Using normal SSB with the stock 2.7kHz. wide crystal filter is there any way to adjust the lower and upper bandwidth frequency ranges other than the TX EQ?
>
> For example how would I adjust so that my 2.7 kHz. bandwidth was from 200Hz. to 2900Hz.?
>
> It is easy to do on the receiver but I cannot figure out how to do this on the transmitter.
>
> 73 - Mike - K9JRI
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>

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Michael Blake

Re: K3s transmit bandwidth adjustment?

Thank you Bob.

Mike - K9JRI

> On Feb 10, 2018, at 13:57, Bob McGraw K4TAX <[hidden email]> wrote:
>
> Based on my measurements the transmit frequency response is limited by the 2.7 kHz SSB filter. It is reasonably flat thus +/-3 dB from 400 Hz to about 2500 Hz. My next measurement points were 300 Hz {-6 dB} on the low end and 3000 Hz {-6 dB} on the high end or 2700 Hz.
>
> Thus your numbers of 200 Hz to 2900 Hz is 2.7 kHz, otherwise about the 6 dB points on the filter. I did not go into the ESSB mode and perform any measurements. These were done in DATA mode, thus negating TX EQ and Speech Processing. I also did similar measurement with TX ALC OFF and in USB mode and in USB with TX EQ set to 0 dB at all frequencies and well below any ALC action.
>
> While I'm always reluctant to measure and report transmit frequency response of a SSB transmit path, namely because many users not understanding what takes place, thus would exclaim "that's horrible frequency response" while in fact just the opposite is true in that it makes for darn good sounding audio.
>
> To answer your question, referring to the Elecraft manual and the Fred Cady book, I find no way to "adjust" the transmit frequency response other than via the TX EQ. On that point, I will emphatically state "it is always better to attenuate a frequency or range of frequencies as opposed to boost a frequency or range of frequencies".
>
> 73
>
> Bob, K4TAX
>
>
>
>> On 2/10/2018 12:04 PM, Michael Blake wrote:
>> Using normal SSB with the stock 2.7kHz. wide crystal filter is there any way to adjust the lower and upper bandwidth frequency ranges other than the TX EQ?
>>
>> For example how would I adjust so that my 2.7 kHz. bandwidth was from 200Hz. to 2900Hz.?
>>
>> It is easy to do on the receiver but I cannot figure out how to do this on the transmitter.
>>
>> 73 - Mike - K9JRI
>>
>>
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>> Message delivered to [hidden email]
>>
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]

Bob McGraw - K4TAX

Re: K3s transmit bandwidth adjustment?

In looking back at my test data, I issue a correction as follows:

It is reasonably flat thus +/-1.5 dB from 400 Hz to about 2500 Hz.

My goof.

73
Bob, K4TAX

On 2/10/2018 1:29 PM, Michael Blake wrote:

> Thank you Bob.
>
> Mike - K9JRI
>
>
>> On Feb 10, 2018, at 13:57, Bob McGraw K4TAX <[hidden email]> wrote:
>>
>> Based on my measurements the transmit frequency response is limited by the 2.7 kHz SSB filter. It is reasonably flat thus +/-3 dB from 400 Hz to about 2500 Hz. My next measurement points were 300 Hz {-6 dB} on the low end and 3000 Hz {-6 dB} on the high end or 2700 Hz.
>>
>> Thus your numbers of 200 Hz to 2900 Hz is 2.7 kHz, otherwise about the 6 dB points on the filter. I did not go into the ESSB mode and perform any measurements. These were done in DATA mode, thus negating TX EQ and Speech Processing. I also did similar measurement with TX ALC OFF and in USB mode and in USB with TX EQ set to 0 dB at all frequencies and well below any ALC action.
>>
>> While I'm always reluctant to measure and report transmit frequency response of a SSB transmit path, namely because many users not understanding what takes place, thus would exclaim "that's horrible frequency response" while in fact just the opposite is true in that it makes for darn good sounding audio.
>>
>> To answer your question, referring to the Elecraft manual and the Fred Cady book, I find no way to "adjust" the transmit frequency response other than via the TX EQ. On that point, I will emphatically state "it is always better to attenuate a frequency or range of frequencies as opposed to boost a frequency or range of frequencies".
>>
>> 73
>>
>> Bob, K4TAX
>>
>>
>>
>>> On 2/10/2018 12:04 PM, Michael Blake wrote:
>>> Using normal SSB with the stock 2.7kHz. wide crystal filter is there any way to adjust the lower and upper bandwidth frequency ranges other than the TX EQ?
>>>
>>> For example how would I adjust so that my 2.7 kHz. bandwidth was from 200Hz. to 2900Hz.?
>>>
>>> It is easy to do on the receiver but I cannot figure out how to do this on the transmitter.
>>>
>>> 73 - Mike - K9JRI
>>>
>>>
>>> ______________________________________________________________
>>> Elecraft mailing list
>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>>> Help: http://mailman.qth.net/mmfaq.htm
>>> Post: mailto:[hidden email]
>>>
>>> This list hosted by: http://www.qsl.net
>>> Please help support this email list: http://www.qsl.net/donate.html
>>> Message delivered to [hidden email]
>>>
>>
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>> Message delivered to [hidden email]