[amsat-bb] Re: Full band transverters for satellite operations?

[Edward Cole]

Tony (and others):

I have had the SDR-IQ (500-Hz to 30-MHz) for 6-months.  I continue to 
discover new aspects of this technology.  Because it uses USB-2.0 I/F 
to the computer bandwidth is not limited by the soundcard A/D 
limitations.  The SDR-IQ receives 190-KHz of spectrum in 
real-time;  this means that a spectral display is this wide.

I have it coupled to a DEMI 144/28 converter for use on 2m eme and 
this permits me to view the complete eme sub-band of most VHF/UHF 
bands.  As faster A/D's become available SDR bandpass will widen and 
upper frequency (sampling rate) rise .  See my webpage:
http://www.kl7uw.com/SDR.htm and
paper for CSVHF-2007 (it will be available on my webpage after the conference)

One area of weakness in the SDR world has been lack of operating 
software.  If you are a programmer then the open-architecture allows 
anything you can dream up.  The rest of us have to wait until new 
software appears.  Currently, I am using Spectravue and Winrad which 
support the SDR-IQ and SDR-14.

Quickly projects like uWSDR will eclipse current SDR's, but for now I 
am finding the SDR-IQ very usable and affordable (and I get my feet 
wet on SDR's).

Since 144-MHz has become my standard IF for microwave's it will find 
good use in my portable mw station (the SDR-IQ is a single pcb 
3.75-inches square and powered via the USB port of the 
laptop).  Similarly for my satellite station.

Latest application is joining in the Experimental 500-KHz Group in 
the USA.  With the SDR-IQ I can capture the whole sub-band at once.


At 12:17 PM 6/14/2007, Tony Langdon wrote:
>At 08:59 PM 6/14/2007, Grant Hodgson wrote:
> >The uWSDR (Microwave SDR) will not need a transverter, it will provide a
> >transceiever operating at the frequency of interest (144, 422, 1268,
> >2400 etc).  It will cover the whole of each band - i.e. 1240-1300MHz.
> >Full duplex cross-band products such as L/S are planned specifically for
> >satellite use.  The hardware is still in development, but progress is
> >being made, and software can be downloaded now and used either in
> >simulator mode or with a Softrock.  The hardware should be available
> >long in advance of the next HEO launch.
>
>Neat.  Hopefully I can look at getting the uWSDR going once I get my
>HPSDR up and running.  Just a comment.  Firstly, I notice there are
>plans for Rx only on 2400 MHz.  I should point out that the VK
>terrestrial weak signal segment is 2403 MHz, so if I was to obtain a
>13cm module, I would want Tx and RX on the 2400-2404 MHz segment (Rx
>for 2401, Tx/Rx for 2403).
>
>I'm also interested how the Ethernet and UDP/IP interface and
>communications goes.  All other SDRs I've seen use a soundcard(ish),
>USB2 or Firewire interface.
>
>
> >Detailed system simulations show that the RF performance will be as good
> >as, and hopefully significantly better than, a transverter/IF combination.
> >
> >More details on the uWSDR website - fell free to join the project if you
> >so desire, any extra help would be appreciated.
>
>Looks interesting.  I can see my future is SDR for the shack. :) One
>aspect of ham SDR development so far which I really like is that the
>various SDRs being designed are using both open hardware and open
>source software, so there's scope for integrating them all together
>and mixing and matching the software packages as the end user sees
>fit.  Or one might want to indulge in a little hacking and improve
>(hopefully! ;) ) the state of the art.
>
>73 de VK3JED
>http://vkradio.com
>
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73,
Ed - KL7UW
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144-EME: FT-847, mgf-1801, 4x-xpol-20, 185w
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