[hpsdr] ALEX - Call for comments

[pvharman at arach.net.au]

Hi Glenn,

At the moment the filters do not overlap with the exception of the 17/15m and 
12/10m ones. 

The filters are really an option - it depends on your location, antennas, local 
stations etc. We expect the large signal performance of Mercury and a QSD 
receiver to be very good but there may be occasions when more filtering would 
be helpful.

Mercury will operate as a wide band spectrum analyzer hence the ability to 
bypass Alex when used in that mode. 

An alternative is to make variants of Alex - we can have broadband versions or 
SWL band versions by changing the L and C in each filter section.  If you can 
tolerate the additional insertion loss ( and this should not be an issue on the 
HF bands) then you can daisy chain multiple Alex cards on the Atlas bus. 

Thanks for your feedback. 

73's Phil...VK6APH




Quoting Glenn Thomas <glennt at charter.net>:

> ***** High Performance Software Defined Radio Discussion List *****
> 
> Hi all.
> 
> Only one question, it's not explicitly clear from your post if the 
> filters (presumably bandpass?) are wide enough to overlap. In 
> addition to Ham radio, I do some SWL'ing and would rather not see 
> this activity precluded due to lack of appropriate filters. Two "aux" 
> filters are likely not enough. If receive filters are needed for 
> Amateur bands, it's reasonable to think they'll be needed for any 
> other frequency as well. This issue may also affect system 
> performance with transverters...
> 
> 73 de Glenn WB6W
> 
> At 06:30 PM 3/5/2007, Graham Haddock wrote:
> >All:
> >
> >Hello, I am Graham, KE9H, the project leader and PCB layout
> >person for ALEX which is the RF preselector filter pack for use
> >with Mercury or other receivers.    Phil, VK6APH, is the designer.
> >
> >ALEX is a multi-band receiver preselector intended to
> >reduce the level of out-of-band signals at the input of a
> >receiver, but it can also be used as a low level transmitter
> >filter.
> >
> 
> <snip>
> 
> >I propose that these ten filter sections would be:
> >160 Meters
> >  80 Meters
> >  40 Meters
> >  30 Meters
> >  20 Meters
> >  17/15 Meters
> >  12/10 Meters
> >   6 Meters
> >User Defined #1
> >User Defined #2
> >
> >There is also a bypass feature, providing no
> >filter or frequency selectivity.
> 
> <snip>
> 
> >Best regards,
> >--- Graham
> 
> 
> _______________________________________________
> HPSDR Discussion List
> To post msg: hpsdr at hpsdr.org
> Subscription help: http://lists.hpsdr.org/listinfo.cgi/hpsdr-hpsdr.org
> HPSDR web page: http://hpsdr.org
> Archives: http://lists.hpsdr.org/pipermail/hpsdr-hpsdr.org/
> 




 1173155804.0