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Any value in using a Microkeyer III with a K3S or K4?

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Courtney Krehbiel KD6X

Any value in using a Microkeyer III with a K3S or K4?

I have a K3... the best radio I've ever owed in my 50+ year ham life. I'm currently using a US Interface Navigator with it for digital modes. This is now sold as the Time Wave Navigator and has worked really well for me for many years.

My understanding is that the K3S and now the incoming K4's have sound cards built-in via the USB port. So perhaps I won't need the Navigator anymore when my K4 eventually arrives. But my question is whether there is still something to be gained using a newer transceiver interface with the K3S or K4? I've been looking at the Microkeyer III with its 24 bit audio processing. Does anyone have any hands-on experience with the Microkeyer III with Elecraft radios? I'm particularly interested if it has a lower noise floor or other features that might not be found in the stock K3S or K4.

Thanks for any input or feedback!

-- Courtney KD6X
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Joe Subich, W4TV-4

Re: Any value in using a Microkeyer III with a K3S or K4?

> Are you aware of any move afoot to support higher bit levels in
> upcoming versions of popular software?

I have no insight into the roadmap for most amateur digital software.
However, I doubt that many developers will expend the effort to do
24 bit processing. The 97 dB (theoretical) - 88 to 90 dB practical
dynamic range of a well designed sound card is quite adequate for most
HF purposes.

The "background noise" in suburban/semi rural areas is on the order of
-135 dBm (~0.05 uV). That means a 90 dB dynamic range can handle from
the background noise to about S9+30 dB. Using an attenuator or reducing
the RF gain in the presence of signals above S9+20 dB can extend the
useful dynamic range by another 20 dB or more.

The only use case for greater dynamic range would be for SDR purposes
where a very wide spectrum was being processed simultaneously or for
extremely "quiet" frequencies (e.g. VHF/UHF with antennas pointed to
a quiet part of the sky - EME or radio astronomy). In the VHF/UHF
case, dynamic range (noise floor) can be improved much more economically
through the use of low noise preamplifiers (and receiving converters).

73,

... Joe, W4TV

On 2021-01-04 7:34 PM, Courtney Krehbiel wrote:

> Thank you for your input Joe! I didn't really think of the software as impacting the functional resolution of the sound card. But upon looking at the block diagram for my Navigator, I can see that's the case. Are you aware of any move afoot to support higher bit levels in upcoming versions of popular software?
>
> Thanks again, and 73!
>
> -- Courtney KD6X
>
> -----Original Message-----
> From: Joe Subich, W4TV <[hidden email]>
> Sent: Sunday, January 3, 2021 7:12 PM
> To: Courtney Krehbiel <[hidden email]>
> Subject: Re: [Elecraft] Any value in using a Microkeyer III with a K3S or K4?
>
>
> Unless the interface is poorly designed (like some "low price"
> amateur only devices), the noise floor is generally set by the IF noise in the transceiver on the higher bands and by the "no signal" atmospheric noise on the low bands.
>
> A 24 bit sound card has the potential to provide greater dynamic range than the more common 16 bit cards but *only* if the software is written to take advantage of the "extra bits". Swapping a 24 bit sound card for a 16 bit sound card will make no difference on existing software like MMTTY, FLDIGI/DM780, etc.
>
> 73,
>
> ... Joe, W4TV
>
>
> On 2021-01-03 6:50 PM, Courtney Krehbiel wrote:
>> I have a K3... the best radio I've ever owed in my 50+ year ham life. I'm currently using a US Interface Navigator with it for digital modes. This is now sold as the Time Wave Navigator and has worked really well for me for many years.
>>
>> My understanding is that the K3S and now the incoming K4's have sound cards built-in via the USB port. So perhaps I won't need the Navigator anymore when my K4 eventually arrives. But my question is whether there is still something to be gained using a newer transceiver interface with the K3S or K4? I've been looking at the Microkeyer III with its 24 bit audio processing. Does anyone have any hands-on experience with the Microkeyer III with Elecraft radios? I'm particularly interested if it has a lower noise floor or other features that might not be found in the stock K3S or K4.
>>
>> Thanks for any input or feedback!
>>
>> -- Courtney KD6X
>
>

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Jim Brown-10

Re: Any value in using a Microkeyer III with a K3S or K4?

I strongly agree with Joe on this. The only thing I'll take exception is
that I suspect his estimates of noise levels are wildly optimistic,
which further supports his observations about sound card dynamic range.
From where I sit with neighbors running WSJT-X modes on the same band,
I look at dynamic range differently.

Consider a local who's 50 dB over S9 on a well calibrated S-meter (yes,
that's optimistic too). If you accept 5 dB/S-unit (I don't), your lower
limit is an S2 signal, or S1 at 6dB/S-unit. Few hams have noise levels
below S5. Depending on band and the direction my antennas are listening,
my noise level in the Santa Cruz Mountains with nearest neighbors ~400
ft from my antennas is S1-S2 with my 6M optimally aimed (to the North
Pole) to reduce noise and S4-5 pointed at either two solar systems in
those closer houses. While still in a Chicago residentail neighborhood,
it was a very good day if I got below S6 on HF on very inferior
antennas. You've got to be in the middle of NOWHERE with a 50dB over S9
neighbor to need more than a 16-bit sound card.

What you DO want is a much better than average sound card, which is why
I've looked to the better units designed for the semi-pro audio market.
One of the qualities of A/D and D/A stages important both to audio pros
and to hams is their amplitude linearity around their noise floor (and
very quiet audio stage feeding the A/D converter.

There's also the issue of how the units address differing sample
rates.WSJT-X works at 16-bits, 48 kHz. If the hardware runs at 96 or 192
kHz, how good are they at the conversion. And so on.

73, Jim K9YC

On 1/4/2021 5:36 PM, Joe Subich, W4TV wrote:

>
>> Are you aware of any move afoot to support higher bit levels in
> > upcoming versions of popular software?
>
> I have no insight into the roadmap for most amateur digital software.
> However, I doubt that many developers will expend the effort to do
> 24 bit processing. The 97 dB (theoretical) - 88 to 90 dB practical
> dynamic range of a well designed sound card is quite adequate for most
> HF purposes.
>
> The "background noise" in suburban/semi rural areas is on the order of
> -135 dBm (~0.05 uV). That means a 90 dB dynamic range can handle from
> the background noise to about S9+30 dB. Using an attenuator or reducing
> the RF gain in the presence of signals above S9+20 dB can extend the
> useful dynamic range by another 20 dB or more.
>
> The only use case for greater dynamic range would be for SDR purposes
> where a very wide spectrum was being processed simultaneously or for
> extremely "quiet" frequencies (e.g. VHF/UHF with antennas pointed to
> a quiet part of the sky - EME or radio astronomy). In the VHF/UHF
> case, dynamic range (noise floor) can be improved much more economically
> through the use of low noise preamplifiers (and receiving converters).
>
> 73,
>
>     ... Joe, W4TV
>
>
> On 2021-01-04 7:34 PM, Courtney Krehbiel wrote:
>> Thank you for your input Joe! I didn't really think of the software
>> as impacting the functional resolution of the sound card. But upon
>> looking at the block diagram for my Navigator, I can see that's the
>> case. Are you aware of any move afoot to support higher bit levels in
>> upcoming versions of popular software?
>>
>> Thanks again, and 73!
>>
>>    -- Courtney KD6X
>>
>> -----Original Message-----
>> From: Joe Subich, W4TV <[hidden email]>
>> Sent: Sunday, January 3, 2021 7:12 PM
>> To: Courtney Krehbiel <[hidden email]>
>> Subject: Re: [Elecraft] Any value in using a Microkeyer III with a K3S
>> or K4?
>>
>>
>> Unless the interface is poorly designed (like some "low price"
>> amateur only devices), the noise floor is generally set by the IF
>> noise in the transceiver on the higher bands and by the "no signal"
>> atmospheric noise on the low bands.
>>
>> A 24 bit sound card has the potential to provide greater dynamic range
>> than the more common 16 bit cards but *only* if the software is
>> written to take advantage of the "extra bits". Swapping a 24 bit
>> sound card for a 16 bit sound card will make no difference on existing
>> software like MMTTY, FLDIGI/DM780, etc.
>>
>> 73,
>>
>>      ... Joe, W4TV
>>
>>
>> On 2021-01-03 6:50 PM, Courtney Krehbiel wrote:
>>> I have a K3... the best radio I've ever owed in my 50+ year ham
>>> life. I'm currently using a US Interface Navigator with it for
>>> digital modes. This is now sold as the Time Wave Navigator and has
>>> worked really well for me for many years.
>>>
>>> My understanding is that the K3S and now the incoming K4's have sound
>>> cards built-in via the USB port. So perhaps I won't need the
>>> Navigator anymore when my K4 eventually arrives. But my question is
>>> whether there is still something to be gained using a newer
>>> transceiver interface with the K3S or K4? I've been looking at the
>>> Microkeyer III with its 24 bit audio processing. Does anyone have
>>> any hands-on experience with the Microkeyer III with Elecraft
>>> radios? I'm particularly interested if it has a lower noise floor or
>>> other features that might not be found in the stock K3S or K4.
>>>
>>> Thanks for any input or feedback!
>>>
>>>     -- Courtney KD6X
>>
>>
> ______________________________________________________________
> 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]

Alan Bloom

Re: Any value in using a Microkeyer III with a K3S or K4?

On 1/5/2021 2:17 PM, Jim Brown wrote:
> You've got to be in the middle of NOWHERE with a 50dB over S9 neighbor
> to need more than a 16-bit sound card.

And that assumes the 50 dB over S9 signal is within the receiver
passband. Otherwise the receiver AGC will increase the volume of the
weak signal to the point where sound card dynamic range is totally not
an issue.

However, as Jim mentions on his web site, it is important to set audio
levels so as not to over-drive the sound card input. And apparently
with some software it is important to set the sound card to the correct
sample rate.

Alan N1AL

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Joe Subich, W4TV-4

Re: Any value in using a Microkeyer III with a K3S or K4?

In reply to this post by Jim Brown-10

> There's also the issue of how the units address differing sample
> rates.WSJT-X works at 16-bits, 48 kHz. If the hardware runs at 96 or
> 192 kHz, how good are they at the conversion. And so on.

The sample rate conversion is a function of the operating system - not
the sound card (CODEC). Windows sets the hardware to operate at what
is defined as the "Default Format" and accepts that sample rate, bits,
channels (e.g., "2 channel, 16 bit, 48000 Hz (DVD quality)"). When an
application opens the sound card for input with different parameters
the operating system does the up/down sampling leaving the original
data stream available for other applications (the ability of multiple
applications/instances to operate in parallel).

The "easiest" (most accurate) conversion is when the sample rates are
integer multiples (e.g., 8000, 12000, 16000, 32000, 48000 Hz). The
least accurate conversions are where the sample rates are non-integer
multiples (e.g. 44100 Hz, 11025 Hz an 48000 Hz.). Generally, bit depth
conversions are "integer multiples" but there is considerable loss of
linearity (at the low end) when downsampling from 24 bit to 16 bit or
16 bit to 8 bit, etc.

73,

... Joe, W4TV

On 2021-01-05 4:17 PM, Jim Brown wrote:

> I strongly agree with Joe on this. The only thing I'll take exception is
> that I suspect his estimates of noise levels are wildly optimistic,
> which further supports his observations about sound card dynamic range.
> From where I sit with neighbors running WSJT-X modes on the same band,
> I look at dynamic range differently.
>
> Consider a local who's 50 dB over S9 on a well calibrated S-meter (yes,
> that's optimistic too). If you accept 5 dB/S-unit (I don't), your lower
> limit is an S2 signal, or S1 at 6dB/S-unit. Few hams have noise levels
> below S5. Depending on band and the direction my antennas are listening,
> my noise level in the Santa Cruz Mountains with nearest neighbors ~400
> ft from my antennas is S1-S2 with my 6M optimally aimed (to the North
> Pole) to reduce noise and S4-5 pointed at either two solar systems in
> those closer houses. While still in a Chicago residentail neighborhood,
> it was a very good day if I got below S6 on HF on very inferior
> antennas. You've got to be in the middle of NOWHERE with a 50dB over S9
> neighbor to need more than a 16-bit sound card.
>
> What you DO want is a much better than average sound card, which is why
> I've looked to the better units designed for the semi-pro audio market.
> One of the qualities of A/D and D/A stages important both to audio pros
> and to hams is their amplitude linearity around their noise floor (and
> very quiet audio stage feeding the A/D converter.
>
> There's also the issue of how the units address differing sample
> rates.WSJT-X works at 16-bits, 48 kHz. If the hardware runs at 96 or 192
> kHz, how good are they at the conversion. And so on.
>
> 73, Jim K9YC
>
> On 1/4/2021 5:36 PM, Joe Subich, W4TV wrote:
>>
>>> Are you aware of any move afoot to support higher bit levels in
>> > upcoming versions of popular software?
>>
>> I have no insight into the roadmap for most amateur digital software.
>> However, I doubt that many developers will expend the effort to do
>> 24 bit processing. The 97 dB (theoretical) - 88 to 90 dB practical
>> dynamic range of a well designed sound card is quite adequate for most
>> HF purposes.
>>
>> The "background noise" in suburban/semi rural areas is on the order of
>> -135 dBm (~0.05 uV). That means a 90 dB dynamic range can handle from
>> the background noise to about S9+30 dB. Using an attenuator or reducing
>> the RF gain in the presence of signals above S9+20 dB can extend the
>> useful dynamic range by another 20 dB or more.
>>
>> The only use case for greater dynamic range would be for SDR purposes
>> where a very wide spectrum was being processed simultaneously or for
>> extremely "quiet" frequencies (e.g. VHF/UHF with antennas pointed to
>> a quiet part of the sky - EME or radio astronomy). In the VHF/UHF
>> case, dynamic range (noise floor) can be improved much more economically
>> through the use of low noise preamplifiers (and receiving converters).
>>
>> 73,
>>
>>     ... Joe, W4TV
>>
>>
>> On 2021-01-04 7:34 PM, Courtney Krehbiel wrote:
>>> Thank you for your input Joe! I didn't really think of the software
>>> as impacting the functional resolution of the sound card. But upon
>>> looking at the block diagram for my Navigator, I can see that's the
>>> case. Are you aware of any move afoot to support higher bit levels
>>> in upcoming versions of popular software?
>>>
>>> Thanks again, and 73!
>>>
>>>    -- Courtney KD6X
>>>
>>> -----Original Message-----
>>> From: Joe Subich, W4TV <[hidden email]>
>>> Sent: Sunday, January 3, 2021 7:12 PM
>>> To: Courtney Krehbiel <[hidden email]>
>>> Subject: Re: [Elecraft] Any value in using a Microkeyer III with a
>>> K3S or K4?
>>>
>>>
>>> Unless the interface is poorly designed (like some "low price"
>>> amateur only devices), the noise floor is generally set by the IF
>>> noise in the transceiver on the higher bands and by the "no signal"
>>> atmospheric noise on the low bands.
>>>
>>> A 24 bit sound card has the potential to provide greater dynamic
>>> range than the more common 16 bit cards but *only* if the software is
>>> written to take advantage of the "extra bits". Swapping a 24 bit
>>> sound card for a 16 bit sound card will make no difference on
>>> existing software like MMTTY, FLDIGI/DM780, etc.
>>>
>>> 73,
>>>
>>>      ... Joe, W4TV
>>>
>>>
>>> On 2021-01-03 6:50 PM, Courtney Krehbiel wrote:
>>>> I have a K3... the best radio I've ever owed in my 50+ year ham
>>>> life. I'm currently using a US Interface Navigator with it for
>>>> digital modes. This is now sold as the Time Wave Navigator and has
>>>> worked really well for me for many years.
>>>>
>>>> My understanding is that the K3S and now the incoming K4's have
>>>> sound cards built-in via the USB port. So perhaps I won't need the
>>>> Navigator anymore when my K4 eventually arrives. But my question is
>>>> whether there is still something to be gained using a newer
>>>> transceiver interface with the K3S or K4? I've been looking at the
>>>> Microkeyer III with its 24 bit audio processing. Does anyone have
>>>> any hands-on experience with the Microkeyer III with Elecraft
>>>> radios? I'm particularly interested if it has a lower noise floor
>>>> or other features that might not be found in the stock K3S or K4.
>>>>
>>>> Thanks for any input or feedback!
>>>>
>>>>     -- Courtney KD6X