[hpsdr] New Hermes 2M Board.

[Laurence Barker]

I'd like to offer some suggestions for a new board please:

Have you considered the "system FPGA" devices eg Xilinx Zynq? Those devices
have been revolutionary in many areas and would enable much more
experimentation in different areas. For example: a complete transceiver with
one rotary encoder and one LCD display interfaced to the ARM part of the
device, meaning you don't need a PC or Raspberry Pi attached, but also
allowing you  to plug them in to extend the functionality. Perhaps a more
capable radio with Android phone user interface (you could probably get
quite close to that with some of John Melton's existing code).

Have you considered using a complete commercially available " FPGA
+interfaces" PCB and having the radio-specific interfaces on a separate PCB
with something like an FMC mezzanine interface connector between them? For
example an interface onto one of the "Zedboard" low cost FPGA products? That
would allow the FPGA part of the product to be replaced with more capable
ones as that technology matures, without having to re-do the entire design
(and without anyone needing to assemble any new circuit boards).

I'm currently working on an RF front end for the Red Pitaya - I have an RF
switching PCB ready to test, and the RF input/output conditioning (with 31dB
attenuators to set ADC/ DAC input and output levels) ready to send to the
PCB manufacturer. This will give it an RF front end similar to Alex but with
two receivers enabled.
http://www.g8njj.org.uk/index.php/software-defined-radio/2442-a-start-in-sdr
-part-4-antenna-switch-routing


For the RF parts - rather than trying to make one very complex PCB, why not
consider having several simpler PCBs that would be more compatible with home
assembly? For example separate TX and RX filter and amplifier boards
constrained to two layer PCB but trying to keep a lower profile so that
several still fit a Hammond enclosure? Possibly a bank of RF bandpass
filters with PIN diode rather than relay switching for receiver (like the
IC7300, I suspect)? 

I'be be intereted in helping out in the development - I can do limited RF
design (I'm a digital rather than analogue designer), general electronic
design, and I'm reasonably competent at C programming as long as it stays
away from the operating system interfaces. 




Laurence Barker G8NJJ

laurence at nicklebyhouse.co.uk

-----Original Message-----
From: Hpsdr [mailto:hpsdr-bounces at lists.openhpsdr.org] On Behalf Of John
Marvin
Sent: 29 May 2017 10:30
To: hpsdr at lists.openhpsdr.org
Subject: Re: [hpsdr] New Hermes 2M Board.

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