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Re: [Yaesu] mp amp keying?

To: "'K1TTT'" <K1TTT@ARRL.NET>, "'Yaesu'" <yaesu@contesting.com>
Subject: Re: [Yaesu] mp amp keying?
From: "Joe Subich, W4TV" <w4tv@subich.com>
Date: Sun, 16 Nov 2008 11:59:12 -0500
List-post: <yaesu@contesting.com">mailto:yaesu@contesting.com>
David, 

The Band Data keying line should work fine.  However, if you 
are getting "sticky" relays, that means the amplifiers have a 
significant back EMF spike when they are unkeyed (enough to 
generate a small arc in the relay on open).  

I would suggest checking all of the T/R relays in the amplifier 
and your antenna switching controller to make sure there are EMF 
suppression diodes across all the coils and/or add a buffer with
600V FET to the keying line. 

73, 

   ... Joe, W4TV 
 


> -----Original Message-----
> From: yaesu-bounces@contesting.com 
> [mailto:yaesu-bounces@contesting.com] On Behalf Of K1TTT
> Sent: Sunday, November 16, 2008 9:45 AM
> To: Yaesu
> Subject: [Yaesu] mp amp keying?
> 
> 
> I have had several mp's develop sticky amp keying relays.  
> This is now my most common reason to have them serviced and 
> would like to avoid this if possible.  I see the band data 
> jack has a tx ground through a 2n3444 transistor which is 
> rated at  60v and 1a, with my hf-2500 amps and a small relay 
> that locks out the antenna switching I measure either 12v or 
> 20v at about 75ma, so it seems that transistor should be more 
> than enough.  Does anyone use that band data output for amp keying?
> 
> 
> David Robbins K1TTT
> e-mail: mailto:k1ttt@arrl.net
> web: http://www.k1ttt.net
> AR-Cluster node: 145.69MHz or telnet://dxc.k1ttt.net
>  
> 
> 
> 
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