[DSP-10] How about 432?

[kd7ts]

On Fri, 16 Nov 2012 16:43:18 -0800, Courtney Duncan  
<cbduncan at earthlink.net> wrote:

>
> "Why not just build the DSP-10 up as a 432 system in the first place?"   
> It could be called the DSP-12 or DSP-70 or something like that.
>
> Indulge me here.  I take all risks.  I'm just asking for a little  
> consultation.

Hi CBD,

I think what you are contemplating is possible. It seems pretty ambitious,  
but possible. 432 does not see much use here locally near Seattle, but it  
can be a useful IF frequency for 24 GHz and higher bands.

A transverter for converting 432 to 144 is not trivial either, but does  
not require any additional software, or modification of the existing  
software and hardware.

I designed a transverter for high side injection, but underestimated the  
amount of gain needed in the transmit chain. The biggest mistake was  
working within the constraints of board size supported by ExpressPCB. The  
whole thing looks cute, but only has a few milliwatts instead of the  
intended 2 watts.(the goal was a replacement for an IC402 for a 24 GHz  
transverter)

When the project is all finished, will you have met the goals of changing  
the design ? In other words, are you doing this as a learning experience,  
or, do you think this will be a useful radio ?

My effort on the transverter design was a learning experience, and not  
particularly cheap. I did enjoy doing it, and learned enough that the next  
iteration might be successful, and I still have a DSP-10 that works as  
intended. Are you confident that after changing the design what remains  
will be useful ?

I know this is well beyond my comfort level.

  Consultation ? Not from here, just more questions.

It is fun to think about. The design that I like was done long ago by  
Yaesu, the FT 736r. Basically plug in band modules with synthesizers in  
each.

73 Mike KD7TS