[Elecraft] K3 and linear amp

[Ian White GM3SEK]

Roger Marrotte wrote:
>I guess as of now I'm out of luck if I want to use my amp with a K3.  I 
>just checked the manual for my AL-811H and "The open frame relay in the 
>AL-811H takes approximately 15ms to switch states".  My K3 is on order. 
>I hope there's a K3 firmware change made before I get my K3, that will 
>allow me to adjust the change over timing.  I'm far from an expert with 
>amps.  I have no idea what an average switch over time is for amps in 
>general.  Ameritron sells a high speed switching option, the QSK-5, 
>that reduces the switching time to 1ms.  It costs around $300.00.  A K3 
>firmware change would sure be less expensive.
>
That firmware change is surely needed, but there is another inexpensive 
way which often works - speed up that open-frame relay.

The circuit shown in the link below uses the existing relay supply rail, 
and it will shorten the switching time of most relays by about one-half. 
The same circuit will also convert many older amplifiers to a modern 
standards +12V, low-current switch interface.

http://www.ifwtech.co.uk/g3sek/in-prac/best-of.htm#speedup


-- 

73 from Ian GM3SEK         'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek