[hpsdr] VHF/UHF transverter for HPSDR

[Georg Prinz]

Hi Ante,

I would like to bring up following question:
Why not to develop a transverter for VHF/UHF? It would not only save
space on our limited Atlas backplane but also engineering power. For
those who don't need the TX-part could populate the RX-part only.

73, Georg, dl2kp



On Sa, 2011-10-01 at 22:52 +0200, Ante Vukorepa wrote:
> ***** High Performance Software Defined Radio Discussion List *****
> 
> On srijeda, 21. rujna 2011. at 23:18, Ante Vukorepa wrote:
> > 1) using Si570 (high grade LVDS version, if possible) as the LO to
> > feed a high IP3 Mini Circuits frequency mixer, then filtering out
> > the higher "image" with a 500MHz-ish low pass filter
> > B1 is probably the best option for initial experimentation and my
> > own (not very demanding) purposes. So that's the route i think i'll
> > go, as soon as i catch some free time and start putting all this
> > down on paper. My plan is to try and design a down converter
> > consisting of fore-mentioned elements (Si570, frequency mixer,
> > filter) plus a microcontroller, that would fit an Atlas card and
> > would be controlled through the bus, via I2C. The vision is to have
> > the ability to bypass and turn all the elements, including the
> > microcontroller, off when not in use, so the impact on the existing
> > HF signal chain is minimal.
> 
> 
> I've put together an initial block diagram for what i've had in mind:
> http://dl.dropbox.com/u/1702513/Block.png
> 
> 
> The board will be 2-layer if possible (to simplify and cheapify things
> initially), with one side dedicated almost purely to ground (separate
> analogue and digital ground planes, of course, perhaps even a
> completely separate plane for the Si570). Omron SMD signal relays will
> be used for pre-amp and filter bypassing and oven control (control in
> the sense of having it completely on or off, not in the sense of PWM).
> An Atmega168 or 328 will control both them and the Si570 providing the
> LO frequency. The Atmega will, in turn, be controlled via an I2C or
> SPI line, by the other boards on the bus, or manually, via a front
> control panel consisting of a rotary encoder, LCD and a few buttons.
> The balun is there to convert the differential Si570 CML output and
> suck out as much decibels as possible to feed a high IP3 frequency
> mixer. The (optional) FM broadcast band-stop filter is there to kill
> the interference from strong nearby FM towers, if needed.
> 
> 
> How am i doing so far?
> 
> -- 
> Ante Vukorepa
> Sent with Sparrow
> 
>  
> 
> 
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