[600MRG] Ultimate 3 must have???

[Brian Pease]

The U3 turns it's tiny RF power amp on and off with a second identical 
MOSFET wired to ground.  This T/R Mosfet receives a +5VDC signal from 
the controller when Transmit starts.  I just brought out this wire and 
use it to turn on a MOSFET that operates my homemade 12 Volt T/R relay.  
It also turns on a MOSFET that shorts out the mike input line to the 
computer during transmit.  In this case, the DC bias for the electret 
mike biases the MOSFET drain.  NPN transistors would also work because 
the 5V control signal can supply some current.  The same line also turns 
on the Class-E amp, which has a big keying MOSFET that applies power to 
the push-pull final. This last is not strictly necessary, but may 
prevent noise in the receiver.
On 11/30/2013 1:56 PM, John Langridge wrote:
> Brian,
>
> How are you controlling T/R?  RF Sense or something else?
>
> thanks,
>
> John XIQ
>
>
> ------------------------------------------------------------------------
> *From:* Brian Pease <bpease2 at myfairpoint.net>
> *To:* 600mrg at w7ekb.com
> *Sent:* Saturday, November 30, 2013 12:49 PM
> *Subject:* Re: [600MRG] Ultimate 3 must have???
>
> Exactly.  Just build it into an old dusty box.  Hans is almost
> overwhelmed with orders now that the word has gotten out. It is great
> for me as I have a 3586C receiver.  The U3 Drives my amp and operates
> the T/R switching and receiver muting.
> On 11/30/2013 1:35 PM, John Langridge wrote:
> > Mike you are going about this all wrong!
> >
> > When something shows up new at the operating position and the wife 
> asks, the right answer ALWAYS is "Oh honey, I've had that for years" ;-p
> >
> > 73,
> >
> > John XIQ
> >
> >
> >
> >
> > ________________________________
> >  From: Mike.WE0H <we0h at yahoo.com <mailto:we0h at yahoo.com>>
> > To: 600mrg at w7ekb.com <mailto:600mrg at w7ekb.com>
> > Sent: Saturday, November 30, 2013 12:33 PM
> > Subject: Re: [600MRG] Ultimate 3 must have???
> >
> >
> > Sounding like I would be an idiot not to order one ;-) Wonder if my 
> wife will chew me another one for ordering more stuff :-( I already 
> bought an auto tuner and a narrow CW filter for that IC-735 that I 
> bought a month or so ago ;-)
> >
> > decisions decisions...
> >
> > Mike
> > WE0H
> > /16
> >
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>
>
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