[Elecraft] Neat K3 Video! - K3 Amp interface questions

[Joe Subich, W4TV]

Jerry, 

> I am presently using a method in which my PC reads the rig freq and 
> generates band-data signals for the amp ( 
> http://www.ab4oj.com/quadra/w4uk.html or 
> http://mywebpages.comcast.net/rwilliams309/QUADRA_interface.html ). 
> This works OK, but always requires the logging computer is on and 
> that the program is running.

It's a non-issue. Both the Quadra and FL-7000 have internal pull-ups. 

Further, the TopTen and microHAM Band Decoders include pull ups 
on their BCD inputs.  The only device that I know of that lacks 
the pull-ups is the Unified Microsystems (W9XT) BCD-10 decoder. 

> Ian, if this is fixable within the K3, will it require a hardware 
> change or can it simply be inverted in software?

It's fixable (if necessary) in the K3 by adding pull-ups on the 
KIO3 board. 

73, 

   ... Joe, W4TV 
 

> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net 
> [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Jerry Flanders
> Sent: Monday, December 03, 2007 12:57 PM
> To: Ian White; elecraft at mailman.qth.net
> Subject: Re: [Elecraft] Neat K3 Video! - K3 Amp interface questions
> 
> 
> 
> At 10:32 AM 12/3/2007, Ian White GM3SEK wrote:
> <SNIP>The problem was simply that, on the issue of compatibility with 
> existing technical standards in the market, nobody picked up the ball.
> 
> ><SNIP>
> >
> >3. Reverse logic in the band data output. Again, this 4-bit encoding 
> >was originated by Yaesu, and has since been adopted and extended by 
> >a range of third-party providers. The standard band data output is 
> >TTL, logic 1 = 5V, logic 0 = 0V.
> >
> >The K3 uses industry-standard band encoding, but the output 
> >interface is not standard. Use of open-drain pulldowns in the K3 
> >means that existing non-Elecraft band data  interfaces will not work 
> >without some modifications and a user-provided positive supply rail.
> 
> Thanks for mentioning this, Ian. I hadn't picked up on this before. 
> One of the major reasons I ordered a K3 was because I assumed the 
> automatic band selection feature on my Quadra would work directly 
> with the K3 after I wired up a new cable.
> 
> I am presently using a method in which my PC reads the rig freq and 
> generates band-data signals for the amp ( 
> http://www.ab4oj.com/quadra/w4uk.html or 
> http://mywebpages.comcast.net/rwilliams309/QUADRA_interface.html ). 
> This works OK, but always requires the logging computer is on and 
> that the program is running.
> 
> Are there any existing devices that would work with the K3 band-data 
> interface as-is? Anybody know of such?
> 
> Ian, if this is fixable within the K3, will it require a hardware 
> change or can it simply be inverted in software?
> 
> Jerry W4UK
>