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K3s SSB transmitting bandwidth?

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K3s SSB transmitting bandwidth?

When using the stock K3s 2.7 KHz. roofing filter and all TX EQ settings are zero (0) what is the normal TX audio rolloff below 300Hz.?

Michael Blake
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Don Wilhelm

Re: K3s SSB transmitting bandwidth?

Michael,

I think the rolloff is not much (in support of those who want ESSB
operation. Much of the rolloff depends on your microphone.
Jim Brown K9YC has long advocated reducing the TX EQ below 500 Hz or so
in order to increase your effective communications power. An
improvement of 3 dB or more can be had by reducing the low frequency
audio since those low frequencies take a lot of the total power and add
little to communications effectiveness.

73 and Merry Christmas,
Don W3FPR

On 12/25/2018 11:03 AM, Michael Blake via Elecraft wrote:
> When using the stock K3s 2.7 KHz. roofing filter and all TX EQ settings are zero (0) what is the normal TX audio rolloff below 300Hz.?
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Elecraft mailing list

Re: K3s SSB transmitting bandwidth?

Thanks Don. The published curves ( https://elecraft.com/pages/k3s-8-215-mhz-first-if-crystal-filter-response-curves <https://elecraft.com/pages/k3s-8-215-mhz-first-if-crystal-filter-response-curves> ) suggest that there will be significant low end rolloff below 300 Hz. But I have not taken the time or effort to attempt to measure it myself. I believe that the ESSB improvements also require a wider filter to be totally effective.

The reason I ask is that when on-the-air testing of my new HyperX Cloud Pro headset there was not much change (none actually) noticed when I rolled 50Hz. And 100Hz. off to -16.

I thought that I had seen actually measurements of the actual rolloff in the past and thought that someone might recall where there were.

Very 73 - Mike - K9JRI

> On Dec 25, 2018, at 11:18 AM, Don Wilhelm <[hidden email]> wrote:
>
> Michael,
>
> I think the rolloff is not much (in support of those who want ESSB operation. Much of the rolloff depends on your microphone.
> Jim Brown K9YC has long advocated reducing the TX EQ below 500 Hz or so in order to increase your effective communications power. An improvement of 3 dB or more can be had by reducing the low frequency audio since those low frequencies take a lot of the total power and add little to communications effectiveness.
>
> 73 and Merry Christmas,
> Don W3FPR
>
> On 12/25/2018 11:03 AM, Michael Blake via Elecraft wrote:
>> When using the stock K3s 2.7 KHz. roofing filter and all TX EQ settings are zero (0) what is the normal TX audio rolloff below 300Hz.?

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W2xj

Re: K3s SSB transmitting bandwidth?

In reply to this post by Elecraft mailing list

The rule for a balanced sound is that the product of the lowest and highest frequency should be between 450,000 and 500,000. So for a 2.7 KHz cutoff that means a low cut of 166 to 185 Hertz, or rounding that could be 200 Hertz.

Sent from my iPad

> On Dec 25, 2018, at 8:03 AM, Michael Blake via Elecraft <[hidden email]> wrote:
>
> When using the stock K3s 2.7 KHz. roofing filter and all TX EQ settings are zero (0) what is the normal TX audio rolloff below 300Hz.?
>
> Michael Blake
> [hidden email] <mailto:[hidden email]>
>
>
>
>
>
>
> ______________________________________________________________
> Elecraft mailing list
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Elecraft mailing list

Re: [Elecraft-K3] K3s SSB transmitting bandwidth?

Bob, good information as was Don’s response but I am looking for a specific piece of information relative the actual response of a K3s on SSB using the stock 2.7KHz. filter and zero TX equalization.

Michael Blake
[hidden email] <mailto:[hidden email]>

> On Dec 25, 2018, at 12:05 PM, W2XJ <[hidden email]> wrote:
>
> The rule for a balanced sound is that the product of the lowest and highest frequency should be between 450,000 and 500,000. So for a 2.7 KHz cutoff that means a low cut of 166 to 185 Hertz, or rounding that could be 200 Hertz.
>> On Dec 25, 2018, at 8:03 AM, Michael Blake via Elecraft <[hidden email]> wrote:
>>
>> When using the stock K3s 2.7 KHz. roofing filter and all TX EQ settings are zero (0) what is the normal TX audio rolloff below 300Hz.?
>>
>> Michael Blake
>> [hidden email] <mailto:[hidden email]>
>>
>>
>>
>>
>>
>>
>> ______________________________________________________________
>> Elecraft mailing list
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Don Wilhelm

Re: K3s SSB transmitting bandwidth?

In reply to this post by W2xj

The cutoff would be higher than 2.7kHz. What you add to the high
frequency end is subtracted from the low end.
The high end is normally about 3kHz which means the low end of the
roofing filter is at about 300Hz.

Yes, ESSB operation would require the 6kHz roofing filter.

73,
Don W3FPR

On 12/25/2018 12:05 PM, W2xj wrote:
> The rule for a balanced sound is that the product of the lowest and highest frequency should be between 450,000 and 500,000. So for a 2.7 KHz cutoff that means a low cut of 166 to 185 Hertz, or rounding that could be 200 Hertz.
>
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Don Wilhelm

Re: [Elecraft-K3] K3s SSB transmitting bandwidth?

In reply to this post by Elecraft mailing list

Michael,

There are curves of the filter response on the Elecraft website - but
with the new website, I cannot give you a link, things have changed.

73,
Don W3FPR

On 12/25/2018 12:10 PM, Michael Blake via Elecraft wrote:
> Bob, good information as was Don’s response but I am looking for a specific piece of information relative the actual response of a K3s on SSB using the stock 2.7KHz. filter and zero TX equalization.
>
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Joe Subich, W4TV-4

Re: K3s SSB transmitting bandwidth?

In reply to this post by Elecraft mailing list

On 2018-12-25 11:54 AM, Michael Blake via Elecraft wrote:
> Thanks Don. The published curves (
https://elecraft.com/pages/k3s-8-215-mhz-first-if-crystal-filter-response-curves
) suggest
> that there will be significant low end rolloff below 300 Hz.

The actual low end is controlled by two parameters: the low cut
frequency in the DSP algorithm and the local oscillator frequency
(where the IF filter is placed relative to the carrier frequency).

In general, the "normal" passband for a 2.7 KHz SSB signal would
be 300 - 3000 Hz. In the K3/K3s that bandpass would primarily be
set by the DSP. In fact, if you look closely at the response of
both the 2700 and 2800 Hz filters you will notice they are not
symmetrical - they have steeper skirts on the high frequency side
than the low frequency side. If the filter were the only determinant
of transmit audio response, one sideband would have less low end
response than the other.

In analog filter SSB designs, one typically set the carrier at -40 dB
on the filter skirt (to improve carrier suppression) and accepted the
low frequency roll off that started between 200 and 500 Hz (depending
on the filter skirts). For the K3/K3S, I'm certain that Elecraft
adjust the "carrier offset" to some degree for normal SSB and ESSB
settings but I don't recall ever seeing response specifications
other than total bandwidth (2.7, 3.0., 3.1, 3.2, 3.2, 3.4, 3.5, 3.6,
3.7, 3.8, 3.9 and 4.0 KHz).

73,

... Joe, W4TV

On 2018-12-25 11:54 AM, Michael Blake via Elecraft wrote:

> Thanks Don. The published curves ( https://elecraft.com/pages/k3s-8-215-mhz-first-if-crystal-filter-response-curves <https://elecraft.com/pages/k3s-8-215-mhz-first-if-crystal-filter-response-curves> ) suggest that there will be significant low end rolloff below 300 Hz. But I have not taken the time or effort to attempt to measure it myself. I believe that the ESSB improvements also require a wider filter to be totally effective.
>
> The reason I ask is that when on-the-air testing of my new HyperX Cloud Pro headset there was not much change (none actually) noticed when I rolled 50Hz. And 100Hz. off to -16.
>
> I thought that I had seen actually measurements of the actual rolloff in the past and thought that someone might recall where there were.
>
> Very 73 - Mike - K9JRI
>
>
>> On Dec 25, 2018, at 11:18 AM, Don Wilhelm <[hidden email]> wrote:
>>
>> Michael,
>>
>> I think the rolloff is not much (in support of those who want ESSB operation. Much of the rolloff depends on your microphone.
>> Jim Brown K9YC has long advocated reducing the TX EQ below 500 Hz or so in order to increase your effective communications power. An improvement of 3 dB or more can be had by reducing the low frequency audio since those low frequencies take a lot of the total power and add little to communications effectiveness.
>>
>> 73 and Merry Christmas,
>> Don W3FPR
>>
>> On 12/25/2018 11:03 AM, Michael Blake via Elecraft wrote:
>>> When using the stock K3s 2.7 KHz. roofing filter and all TX EQ settings are zero (0) what is the normal TX audio rolloff below 300Hz.?
>

Bob McGraw - K4TAX

Re: K3s SSB transmitting bandwidth?

In reply to this post by Elecraft mailing list

Just made a quick sweep of my K3S in DATA A mode, no EQ, No SP, and find
that it will pass 70 Hz with little to no attenuation. On the high end
it will pass 3000 Hz but greatly attenuates 3100 Hz. This is done with
the stock filter of 2.7 kHz.

At this point in time, I don't have a suitable attenuator and cable to
make measurements from the MIC input.

73

Bob, K4TAX

On 12/25/2018 10:03 AM, Michael Blake via Elecraft wrote:

> When using the stock K3s 2.7 KHz. roofing filter and all TX EQ settings are zero (0) what is the normal TX audio rolloff below 300Hz.?
>
> Michael Blake
> [hidden email] <mailto:[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]
>

Elecraft mailing list

Re: K3s SSB transmitting bandwidth?

Thanks Bob.

Very 73 - Mike - K9JRI

> On Dec 25, 2018, at 4:21 PM, Bob McGraw K4TAX <[hidden email]> wrote:
>
> Just made a quick sweep of my K3S in DATA A mode, no EQ, No SP, and find that it will pass 70 Hz with little to no attenuation. On the high end it will pass 3000 Hz but greatly attenuates 3100 Hz. This is done with the stock filter of 2.7 kHz.
>
> At this point in time, I don't have a suitable attenuator and cable to make measurements from the MIC input.
>
> 73
>
> Bob, K4TAX
>
>
> On 12/25/2018 10:03 AM, Michael Blake via Elecraft wrote:
>> When using the stock K3s 2.7 KHz. roofing filter and all TX EQ settings are zero (0) what is the normal TX audio rolloff below 300Hz.?
>>
>> Michael Blake
>> [hidden email] <mailto:[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]
>>
>
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Bill Frantz

Re: K3s SSB transmitting bandwidth?

In reply to this post by Bob McGraw - K4TAX

This is good data for those running sound card modes such as FT8.

Thanks - Bill AE6JV

On 12/25/18 at 1:21 PM, [hidden email] (Bob McGraw K4TAX) wrote:

>Just made a quick sweep of my K3S in DATA A mode, no EQ, No SP,
>and find that it will pass 70 Hz with little to no attenuation.
>On the high end it will pass 3000 Hz but greatly attenuates
>3100 Hz. This is done with the stock filter of 2.7 kHz.
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ANDY DURBIN

K3s SSB transmitting bandwidth?

In reply to this post by Elecraft mailing list

"This is good data for those running sound card modes such as FT8."

If you do FT8 right you only need a TX bandwidth of 500 Hz (low 1,500 high 2000). Any more than that is only needed for those who insist on not using split and more than a few of those are over-modulating and filling the spectrum with double wide and triple wide audio harmonics.

Andy. k3wyc
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