K3 firmware upgrade 1.55

[David Andrews-3]

On my K3 (#126) the latest firmware version (possibly previous ones also)
reset the RS232 speed to 38,400. If you lose serial connection, check
Config:RS232 to ensure software and K3 are talking at the same speed.

 

Advice please - the ATU BYPASS feature - is it a real bypass leaving no
stray capacitance or inductance in the path (unlike the K2)?

 

David G4CWB

 

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[M0XDF]

Yes, as far as I know


On 30/12/07 15:43, "David Andrews" <[hidden email]> sent:
> Advice please - the ATU BYPASS feature - is it a real bypass leaving no
> stray capacitance or inductance in the path (unlike the K2)?
--
Everything secret degenerates, even the administration of justice; nothing
is safe that does not show how it can bear discussion and publicity.
-Lord Acton, historian (1834-1902)


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[Ed K1EP]

If I recall, according the Aptos, there is capacitance/inductance
left in when it says Bypass to match the impedance of the bypassing
ATU circuitry.

At 12/30/2007 10:53 AM, David Ferrington, M0XDF wrote:

>Yes, as far as I know
>
>
>On 30/12/07 15:43, "David Andrews" <[hidden email]> sent:
> > Advice please - the ATU BYPASS feature - is it a real bypass leaving no
> > stray capacitance or inductance in the path (unlike the K2)?
>--
>Everything secret degenerates, even the administration of justice; nothing
>is safe that does not show how it can bear discussion and publicity.
>-Lord Acton, historian (1834-1902)
>
>
>_______________________________________________
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[Bill Steffey NY9H]

ed is correct....

check the schematic  you'll see that there are components still in
line  when in bypass.

bill

At 10:23 AM 12/30/2007, Ed K1EP wrote:

>If I recall, according the Aptos, there is capacitance/inductance
>left in when it says Bypass to match the impedance of the bypassing
>ATU circuitry.
>
>At 12/30/2007 10:53 AM, David Ferrington, M0XDF wrote:
>>Yes, as far as I know
>>
>>
>>On 30/12/07 15:43, "David Andrews" <[hidden email]> sent:
>> > Advice please - the ATU BYPASS feature - is it a real bypass leaving no
>> > stray capacitance or inductance in the path (unlike the K2)?
>>--
>>Everything secret degenerates, even the administration of justice; nothing
>>is safe that does not show how it can bear discussion and publicity.
>>-Lord Acton, historian (1834-1902)
>>
>>
>>_______________________________________________
>>Elecraft mailing list
>>Post to: [hidden email]
>>You must be a subscriber to post to the list.
>>Subscriber Info (Addr. Change, sub, unsub etc.):
>>  http://mailman.qth.net/mailman/listinfo/elecraft
>>
>>Help: http://mailman.qth.net/subscribers.htm
>>Elecraft web page: http://www.elecraft.com
>
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[Vic K2VCO]

David Andrews wrote:

> Advice please - the ATU BYPASS feature - is it a real bypass leaving no
> stray capacitance or inductance in the path (unlike the K2)?

The ATU BYPASS in current firmware adjusts the ATU to cancel out the
stray L/C in the path through the tuner to provide a 50 ohm match.

Early beta firmware simply switched all ATU components to zero. But the
problem was that then the strays from the traces, relays, etc. caused a
residual SWR.

What you may be looking for is a pair of coax relays in the K3! This
does not exist.

--
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco
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