the KAT3 to be quite low. I would suggest adding a supplemental
inductor in series with the antenna wire. I am not going to suggest
just how much, but you can experiment. Using an antenna analyzer might
> Ok, Chuck, thanks alot. That explains all. I was thinking it was a pi
> with two capacitors.
>
> So anyway, for BCB reception, the capacitor doesn't do much and you
> would pretty much want to have maximum L, right?
>
> 73,
> Drew
> AF2Z
>
>
> On Sat, 19 Jul 2008 09:03:02 -0700 (PDT), Chuck, AE4CW wrote:
>
>
>> Vic and Drew,
>>
>> The ATU in the K3 is a low-pass "L" design which has a series inductance and
>> *either* an input (Ct) *or* output (Ca) shunting capacitance. There is only
>> one capacitance in this desigh, not two. The single capacitance is switched
>> between the input (Ct side - transceiver) or output (Ca side - antenna) of
>> the inductance. So, when you are in CONFIG:KAT3 --> LCSET --> ATU TUNE,
>> tapping ANT switches the capacitance between the input and output of the
>> inductance. You can hear the relay switch when tapping ANT and sometimes
>> hear a distinct difference in the received signal.
>>
>> In general the capacitance will need to be on the input (Ct) side when the
>> antenna impedance is below 50 ohms and on the output side when the antenna
>> impedance is greater than 50 ohm.
>>
>> You can look at the circuit design in the K3 schematics (documentation page
>> on the web) if you would like to get a more detailed understanding. Or,
>> you could also look at a program like TLW (transmission line wizard) that
>> will calculate and show you a picture of the correct values for a low-pass
>> "L" ATU with any given values of antenna impedances.
>>
>> Hope this helps! 73,
>>
>> Chuck, AE4CW
>>
>>
>
> _______________________________________________
> 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>
> No virus found in this incoming message.
> Checked by AVG -
http://www.avg.com
> Version: 8.0.138 / Virus Database: 270.5.2/1561 - Release Date: 7/18/2008 6:35 PM
>
>
>
>
Subscriber Info (Addr. Change, sub, unsub etc.):