[amsat-bb] Re: Full band transverters for satellite operations?
kl7uw at acsalaska.net
Thu Jun 14 23:36:25 PDT 2007
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:
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
>Sent via AMSAT-BB at amsat.org. Opinions expressed are those of the author.
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Ed - KL7UW
BP40IQ 50-MHz - 10-GHz www.kl7uw.com
144-EME: FT-847, mgf-1801, 4x-xpol-20, 185w
DUBUS Magazine USA Rep dubususa at hotmail.com
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