[amsat-bb] Re: Full band transverters for satellite operations?
mat_62 at netcommander.com
Thu Jun 14 19:24:38 PDT 2007
I find myself kind of curious on the question of whether this will
be a more or less economical way of satellite ops than a traditional
satellite radio? For the moment I had to sell my gear and will be
looking to dive back in about the time the HEO birds launch. I still
have my computer, of course, and would love to go the SDR route when I
set up again if it's economically feasible for me.
Grant Hodgson wrote:
> Tony Langdon wrote:
>> 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.
> There might be a cut-down, 2.4GHz-only version, but the only cost
> savings would be the TX power amplifier (100mW-200mW o/p) on the RF
> board and maybe the TX D/A converter on the baseband board, which is
> only a few dollars and might be offset by the fact that it would be a
> different build. If there is a lot of demand we'll look into the
> possibility of it but I don't think the cost savings will be significant.
> 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).
> The 2.3-2.4GHz amateur band is the most fragmented band that we have;
> there are at least 6 regional variants that I'm aware of. One of the
> goals is that we want to cover the whole 2.3-2.45GHz band, and we now
> have a paper design that will do just that without compromising key
> parameters such as out-of-band filtering etc. I'm not aware of any
> other amateur radio product that will cover the whole 150MHz at 13cms.
>> I'm also interested how the Ethernet and UDP/IP interface and
>> communications goes.
> I believe that the transmission of the digitised audio has already been
> successfully demonstrated over Ethernet using UDP. The use of Ethernet
> allows for long cable runs enabling the uWSDR to be mounted at the
> masthead and just running power and CAT5 cable into the shack. No need
> for lengthy runs of coax.
> All other SDRs I've seen use a soundcard(ish),
>> USB2 or Firewire interface.
> The uWSDR approach is similar to that of the HPSDR, i.e. we have
> designed our own sound card, and after some considerable work we have
> opted for the same very high performance D/A converter that the HPSDR
> uses. This way we have absolute control of all the key parameters, and
> it's also cheaper than buying a Delta-44.
> Sent via AMSAT-BB at amsat.org. Opinions expressed are those of the author.
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