[Elecraft] KAT500 and TX delay feature request

Igor Sokolov ua9cdc at gmail.com
Thu Dec 6 14:41:09 EST 2012


I recently got THP HL1.1KFX amplifier to be used with KX3 and possibly other 
transceivers when going on expeditions. The reason I got THP instead of 
KPA500 is because I got this amp pretty cheap and it weights only 9 Kg. I 
immediately started to consider various antenna tuner options. MFJ has got 
994B but many users found it to be unreliable at 600W. Their more powerful 
tuner (up to 1500W) is pretty expensive and heavy. Finally I have chosen 
KAT500 and just have placed my order. But prior to that I had spoken to 
Elecraft tech support and found out the following.
KAT 500 has PTT interrupt line that controls PTT of the amp.That is when 
KAT500 has to retune it drops PTT of the amp to do the retune at reasonably 
low power level. At the same time if I change the frequency to one where SWR 
is high and tuner already "knows" the setting for this frequency, it 
switches to a new setting without dropping amplifier's PTT. The switching 
time of the relays used in KAT500 is (as I was told) 20-25msec. The 
switching time of the TR relay in the amp (from specs) is less then 10 msec
That means hot switching of the relays in KAT500 every time I change 
frequency from one sub band to another or from one band to another.
I think a provision of  programmable TX delay in the firmware of KAT 500 
would allow to avoid such a situations. I was told by tech support that this 
feature is going to be implemented soon. Knowing that Elecraft always keep 
their word I have light heartedly placed my order.
Thank you Elecraft for just one more excellent product which I hope will 
find a lot of customers.

73, Igor UA9CDC
 



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