[hpsdr] While waiting on the mighty THOR...

[Kurt Loken]

Thanks for the info Don.  I think I'm going to go this
route unless I hear better ideas from the folks here
or find something better with my googling this
weekend.

I have a few computer power supplies that are
junked...good idea using the case with the fan as the
home. 

Curious about the T/R relay...  Which one did you use?
 Do you know how fast yours is?  The QRP rigs I've
built used diodes or other circuitry to do their
internal T/R switching.   I don't have any experience
dealing with T/R switching when an external amp is
involved.  I wonder how QSK a relay set up will be? 
Since the flexradio uses a relay, it can't be that
bad.  A relay would be easier to deal with I would
think.

Regards,

Kurt - ae6uj



--- Don Kay - KI6FOM <dbk-forums at cox.net> wrote:

> 
> Hi Kurt...
> 
> Kurt Loken wrote:
> > ***** High Performance Software Defined Radio
> Discussion List *****
> > 
> > So any suggestions on good, but inexpensive,
> amplifiers to use while we wait for THOR?
> > 
> > I saw mention on here of the CCI amp: 
> > 
> > http://www.communication-concepts.com/an779L.htm
> > 
> > Does this thing hold up well to CW and digital
> modes as well as voice?
> 
> I bought one of these a while ago for use with my
> softrock 6.1.
> I just finished assembling the board but I haven't
> operated it as of
> yet so I can't comment on that. The literature CCI
> sends with the kit
> recommends driving it to 8-9 watts when using high
> duty cycle modes.
> 
> The literature also states that when using the exact
> parts recommended
> by Motorola the transistors are biased a little hard
> and there is potential
> for thermal runaway. They supply both the Motorola
> specified bias resistors
> and a couple of alternates to reduce the bias a
> little. They also say you
> should limit the supply voltage to 12.5 volts and
> suggest that a cooling
> fan will lengthen the life of the transistors.
> 
> The kit is pretty high quality and a fairly easy
> build if you have some
> experience. The board isn't silk screened so you
> have to place the parts
> by looking at the parts placement drawing in the app
> note and by mentally
> bouncing the board layout against the schematics.
> The step by step
> instructions fit on one double sided page and
> contain some helpful hints
> as well.
> 
> I am building mine into a case I scrounged from a
> burned out PC power
> supply. This is working pretty well since it has a
> fan and enough room
> for the amp, a T/R relay and one of CCI's low pass
> filter kits (and the
> price was right). You would need something bigger to
> handle additional
> filters if you were going to cover additional bands.
> 
> Sorry I can't give you "on the air" experiences but
> hopefully this is
> of at least some help to you.
> 
> 73 - Don (ki6fom)
> 
> > 
> > Any other 20W kits out there that people like?  I
> need something for my softrock RXTX v6.2 that I
> ordered.  I would prefer a kit to a fully homebrewed
> system.
> > 
> > Thanks,
> > 
> > Kurt - ae6uj
> > 
> > 
> >        
> >
>
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> 


       
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