[Elecraft] K3 BETA FIRMWARE RELEASE -- MCU rev 1.94

Wed May 14 07:47:30 EDT 2008

Guys,

There is another way to solve the CW spot problem.

It's called get on the air and work CW.  You will quickly develop the skill
of zero beating by ear.
You will find that most CW ops don't use any zero beating gizmo.  Much
faster and easier to do it by ear.

Another thing.  Narrow filter passbands help.  If you're trying to zero beat
a CW signal with a 2.8KHz filter, it can be an exercise in futiltiy.   And
if a human can't do it,  don't expect some computerized gizmo to do it well
either.

Practically speaking,  if you've dialed in a 200- 400Hz CW bandwidth and you
peak the signal in the passband,  your going to be at most 100Hz off.   That
is really plenty good enough for most situations.

How accurate can zero beating by ear be?   The data points I have are from
RTTY.   My display indicator reads out deviation from zero  in 5 Hz
increments.    I can usually get within 10-20 Hz by ear!   I'm going to
assume the CW accuracy is similar.

73 de Brian/K3KO

Bob Cunnings wrote:
> 
> Unfortunately I see little improvement in the CW auto-spot feature,
> broken in the last release. It is still much less accurate than the
> original algorithm, and less consistent in it's behavior.
> 
> Try this - tune in a good steady (S6 or S7) cw signal. Set tuning to
> FINE, enable CWT and then press SPOT repeatedly, observing the
> frequency display. The beta version (like 1.88) settles on a
> considerably different frequency almost every time - moving 5 Hz or
> more commonly, and sometimes as much as 20 Hz or more. There is a
> tendency to tune low. The original version, on the other hand, rarely
> moves more than 1 or 2 Hz with each auto-spot invocation, bearing out
> the fact that it is more accurate in general, or less likely to get
> confused (by noise, varying morse code speed etc.).
> 
> Since I have two K3 units here, I set one up with 1.78/1.58 and the
> other with the beta firmware, and then compared their auto-spot
> behavior side by side on the same received signal using an antenna
> switch. The difference is quite pronounced. Here are some series of
> freqs (last three digits) resulting from 10 successive invocations of
> auto-spot on the same steady S7 signal on 40 meters (at 13 wpm or so,
> fortunately a long winded transmission):
> 
> v178/158 (TEXT DEC threshold = AUTO)
> 125, 125, 125, 129, 130, 130, 127, 128, 129, 129
> 
> beta (TEXT DEC threshold = AUTO)
> 115, 118, 124, 079 (!), 106, 106, 124, 107, 112, 100
> 
> beta (TEXT DEC threshold = 5)
> 124, 123, 109, 116, 118, 122, 117, 116, 120, 123
> 
> The newer firmware version tends to "bounce around" more with a
> tendency to tune low, often requiring multiple invocations of
> auto-spot to hit the right pitch, whereas the original algorithm
> generally tunes right the first time. With threshold set to 5 in the
> beta version auto-spot is a bit better, but all too often it takes
> multiple tries to hit the right pitch, as it still tends low. If I set
> the threshold much higher, it doesn't want to tune at all for signals
> that the original algorithm handled easily.
> 
> I'm not sure what the "improvements" to auto-spot introduced in 1.88
> were supposed to do, but IMO the feature is still negatively affected
> by the attempt. A side by side comparison of the two versions, on the
> same signal, is very revealing in this case  -  can someone else try
> this?
> 
> Too bad, since I use the feature a lot it's back to 1.78/1.58 for now.
> It "just works".
> 
> Bob NW8L
> 
> 
> 
> On Mon, May 12, 2008 at 7:08 PM, wayne burdick <n6kr at elecraft.com> wrote:
>> Thanks to your input on the last firmware release (1.88), we've made a
>> number of important improvements.
>>
>> For the first time, we're posting new firmware as "beta." Upgrading is
>> optional: if you want to minimize your risk, you might want to wait until
>> we've blessed it as a normal production firmware release. (Or until all
>> your
>> friends have it and you're a little jealous.)
>>
>> We'd love to have as many thrill-seekers as possible take the plunge and
>> load the new firmware now. We think it's greatly improved, and it will
>> certainly clear up many of the issues noted over the past week. Even
>> though
>> we're headed to Dayton in a couple of days, we'll be monitoring closely
>> for
>> any additional issues.
>>
>> For release notes and instructions on how to load beta firmware, please
>> see:
>>
>>  http://www.elecraft.com/K3/k3_software.htm
>>
>> The instructions (linked from within the release notes) explain how to
>> create a separate folder for the beta revision. This will allow you to
>> easily revert to an older revision if you find it necessary. Hopefully
>> not!
>>
>> For your convenience I've also provide the release notes below.
>>
>> 73,
>> Wayne
>> N6KR
>>
>> * * *
>>
>> MCU 1.94 / DSP 1.73, 5-12-08
>>
>>  * VOX: Increased sensitivity. Typical VOX GN settings now ~30-50.
>>
>>  * VOICE MONITOR: Eliminated "scratchy" artifacts with compression set to
>> high levels.
>>
>>  * FM DEVIATION ADJUSTABLE:  Use CONFIG:FM DEV menu entry (default: 5.0
>> kHz).
>>
>>  * Flash memory driver improved to prevent occasional receive dropouts,
>> "ERR
>> PL1", and
>>    "FPF LOAD PENDING" messages.
>>
>>  * XMIT SWITCH IN MENU: Tapping XMIT while in menu correctly starts/ends
>> transmit.
>>
>>  * PASSBAND SHIFT BELOW "0.00" CORRECTED: The SHIFT control no longer
>> allows
>>    continued rotation below 0.00. (This was occurring only with sidetone
>> pitch < 500 Hz.)
>>
>>  * SQUELCH/RF GAIN CONTROL CHANGES: By default, the RF/SQL concentric
>> pots
>>    control main and subreceiver RF gain, and squelch is controlled by two
>> CONFIG menu
>>    entries (SQ MAIN and SQ SUB). But setting SQ MAIN to "=SUB POT"
>> assigns
>>    SUB RF/SQL pot to both main and sub squelch, and in this case, the
>> main
>> RF/SQL
>>    pot controls both main and sub RF gain. Setting SQ MAIN back to a
>> numeric
>> value
>>    restores the default assignments. Note: Squelch applies only to FM
>> mode
>> at present.
>>
>> ---
>>
>> http://www.elecraft.com
>>
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