[Elecraft] Fix the old amplifier......leave the K3 alone!

[Fern Rivard]

Hi Ian and the group:

    I would suggest that you fix/modernize your old amplier and leave the K3 as is!  The problem is NOT with the K3 but rather your amplifier. Upgrade the darn linear with more modern faster switching relays and vacuum relays are not that expensive if you shop around for some good used ones.

    73 from Fern VE7GZ with a fine K3 transceiver






----- Original Message ----- 
From: "Ian White GM3SEK" <gm3sek at ifwtech.co.uk>
To: <elecraft at mailman.qth.net>
Sent: Thursday, March 20, 2008 11:31 AM
Subject: Re: [Elecraft] K3 and linear amp


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
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