[Elecraft] KAT500 LC settings recall -- complete explanation (including auxBus tradeoffs)

[Wayne Burdick]

ab2tc wrote:

> ...the question is if it's worth doing to save that one little
> squirt of RF needed to tell the tuner the exact frequency.


At present the KAT500 works exactly the same as the KAT3:

(1) On any band change or antenna change, the last-used LC settings  
for that band and antenna are immediately recalled.

(2) Every time you transmit, the VFO frequency is determined (using RF  
sensing in the case of the KAT500). This is then converted to a  
segment number within the present band. The segment number is used to  
look up LC settings from the current segment or from the closest one  
for which LC settings are available. If the LC settings need to be  
changed, this is accomplished very quickly -- typically in 5 to 10 ms.

When we first wrote the KAT3 firmware, we tried having LC settings  
recalled as you tune, in receive mode. This was extremely distracting.  
It would be even more so with the KAT500 since it has much larger  
relays.

So what we're talking about now is whether it would be worth sending  
frequency data from the K3 to the KAT500--at the time of keying--over  
either the auxBus or the RS232 port. The answer, IMHO, is no. In  
either case it would take approximately the same amount of time to  
send the data as it would for the KAT500 to do RF sensing of the VFO  
frequency.

If someone has a better idea or would like to explain their operating  
scenario further, I'm all ears.

73,
Wayne
N6KR