[hpsdr] Triple Mercury Directional Steering program

[Joe Martin K5SO]

PowerSDR v1.19.3.4.directional1 (K5SO 16JUN2011) is available for  
download from

http://www.k5so.com/HPSDR_downloads.html

This new Windows program is a modification of the W5WC PowerSDR  
program and implements three Mercury receiver boards simultaneously.   
The program provides a new user control to permit directional steering  
and deep nulling of stations.  The user has direction control of a  
three antenna array and phase/gain control of the two non-reference IQ  
data streams as well as user control over which Mercury receiver is to  
be used as the reference source.

All Mercury boards must be loaded with Mercury firmware v6.6 or later  
and Metis needs firmware v1.3 or later.   Presently Ozy/Magister are  
not supported in this program but will be supported and posted shortly.

Tests have shown that a gain of up to about 4.8 dB is possible over  
the single Mercury case in the desired direction by careful adjustment  
of the angle direction control phase controls of the non-reference IQ  
streams.  Theoretical max gain of a three Mercury system is 4.77 dB  
over a single Mercury system.  Independent gain control of the non- 
reference sources are included in the event that the gain of the three  
independent antenna feed systems are not quite equal.

Bench tests show nulls as great as 70 dB; however, on-air adjustments  
typically yield nulls in the 50 dB range or sometimes less depending  
upon the band conditions.

Of course, all three Mercury receivers must use a common 122.88 MHz  
clock and be phase locked to the 10 MHz Atlas bus line from Excalibur  
for optimum results.

The program will run with only a single Mercury installed but, of  
course, no directional control or nulling will be operational with  
only a single Mercury board present; in case you wish to preview the  
program to see how the user-interface of the program looks and how the  
controls move.  To my knowledge, Mercury firmware v6.6 is backward  
compatible with the existing HPSDR programs except that only a single  
receiver is implemented in each Mercury FPGA. This fact precludes  
operating multiple receivers from a single Mercury board if v6.6 is  
loaded in the Mercury FPGA; VFO A and VFO B operations are still  
functional, however.

Thanks, Joe K1RQG, for helping me test the program under challenging  
on-air conditions and for all the great feedback on design of the user- 
interface.  Additional comments and suggestions are welcome, of course.

73,  Joe K5SO