[hpsdr] Using multiple Penelope boards

[Selmeczi János]

Hi Phil and Jeremy,

Thank you for the fast reply. I will start to look into the verilog code. I know, I must calibrate somehow the system and that means not only the Penelope boards, but the whole RF chain from the board to the antenna currents. I plan to put the PA and the impedance matching network at the base of each antenna, so I will have a properly terminated line from the shack to the antenna. On the receiving side I plan to have a resistor loaded antenna with some high IP preamp, so the mutual coupling will not play at receiving and once again I will have a properly terminated line to the shack. To make the control easier, during transmission I would like to measure / monitor the phase and magnitude of the antenna currents using proper current sensors and the receiving chain.In this way I have to calibrate only the receiving chain and make a closed loop phase control for transmitting. In the long run I would like to have a 4 square array for 80 to 20 meters bands.So it will be a lot of work, I think. The first step will be to implement the modifications Phil suggested.

73, Jani HA5FT

  Phil Harman <phil at pharman.org>, ezt írta: 
  
  Hi Jani,

It should be possible to use multiple Penelope boards in the way you suggest.

I expect that you will want to send the same I & Q samples to each
Penelope board, and the same frequency, but vary the phase of the signal
it generates.  I think you will need to calibrate each board since just
because you set the phase to say 90 degrees will not ensure that is
actually sent.  This is because of differences in the phase/frequency
response of the LPFs etc.

The HPSDR USB protocol does allow for an address to to be send in the
Command & Control data so that data can be sent to individual boards. This
is uses to select different Mercury boards and could be extended for
Penelope boards.

Adding a phase shift for each of the Penelope boards to the USB protocol
would be quite straightforward.

This will mean changes to the PC code, Ozy/Metis and Penelope code. I've
recently added a new nWire signal on Atlas C18 that is used to set the
output power level for PennyLane. It would be simple to add a board
address and phase angles to this data.  That way your changes would not
been seen by regular Penelope/PennyLane/Mercury boards and would maintain
compatibility.

I suggest your starting point is to study the latest USB Protocol (V1.29)
document in \trunk\Documentation to get a feel for how the current
commands are sent.

An interesting project, thanks for the question.

73 Phil...VK6APH


> ***** High Performance Software Defined Radio Discussion List *****
>
> On Jan 24, 2011, at 2:46 AM, Selmeczi János wrote:
>
>> Could sombody tell me, is it possible to use multiple Penelope boards on
>> the same Atlas bus. And if it is possible, what kind of modification
>> have to be made. i.e. changing Penelope and / or Ozy verilog code,
>




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