[hpsdr] A chirp and a Whisper - very long post Part 1 of 3

[Phil Harman]

All,



This is a very long post and won't fit in one email so I've split it into 3 
parts.



Many will be aware of the work undertaken by Bill, KD5TFD, to develop FPGA

code that enables Penelope to operate as a stand alone WSPR beacon.  Not

only does his code allow a full implementation of the WSPR protocol, without

the need to connect to a PC, it also enables multiple beacons to operate

simultaneously on multiple bands.  This is the dual of multiple independent

receives in a Mercury - multiple independent transmitters in a Penny.



More details of Bill's work can be found here:



< svn://64.245.179.219/svn/repos_sdr_hpsdr/trunk/PennyWSPR >



There's a README file at:

< svn://64.245.179.219/svn/repos_sdr_hpsdr/trunk/PennyWSPR/README.txt  >



One of the advantages we have in the way that HPSDR has evolved is the

ability to try new modes without the need to build or buy new hardware.

Here's another example.



Many  CW operators will remember the time when a CW report, say 559, also

sometimes included a 'C' at the end (e.g. 559C) which indicated the received

signal had a 'chip' i.e. unstable when keyed, FM etc.



Chirp was regarded as an undesirable feature and best to let the operator

know.  There was also the practice of adding an 'H' to the report

indicating Hum.  The story goes that the difficulty in obtaining high

voltage smoothing capacitors in Eastern Europe resulted in some operators

applying  un-smoothed rectified mains to the anode/plate of the PA stage

giving it a distinctive err... note. However, a story for another day

perhaps.



The introduction of digital/HDTV in many parts of the world has triggered 
the removal of the analogue TV broadcasters that are/were located adjacent 
to

the 6m band.  Magic Band operators often use these stations as an indicator

of propagation conditions.  Since they typically run much higher ERP than

Amateur stations, 10's of kW, they were/are an ideal source of propagation

beacons.



With the removal of these services in many parts of the world 6m operators

loose a very valuable source of propagation information.  It's just this 
problem that

has lead Andrew Martin, VK30E,   to develop an alternative that can be used

in either a RADAR or beacon mode.



. continued in part II


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