[hpsdr] FW: Hermes

[W2XJ]

Sorry for the double post - email fine tuning issue.


On 8/11/10 12:23 PM, "W2XJ" <w2xj at nyc.rr.com> wrote:

> ***** High Performance Software Defined Radio Discussion List *****
> 
> Subject: Re: [hpsdr] Hermes
> 
> I think at this point USB is just an unnecessary bottleneck to
> experimentation with Hermes. Beyond the complexity of supporting two
> hardware interfaces, the ongoing issue of supporting two sets of drivers for
> software could be a problem. There is not much difference between a limited
> length USB cable between the radio and the computer and an Ethernet
> crossover cable of the same length. On the other hand, Ethernet permits
> wireless connections, fiber optic and wide area connection which will permit
> things previously extremely difficult for the experimenter.
> 
> 
> On 8/10/10 10:25 PM, "Rob Frohne" <rob.frohne at wallawalla.edu> wrote:
> 
>> ***** High Performance Software Defined Radio Discussion List *****
>> 
>> Hi Phil,
>> 
>> That is more pins than I thought (without looking).  I'm still in favor
>> of the Ethernet, but I was trying to make sure that there wasn't an easy
>> solution that would make everyone happy.
>> 
>> 73,
>> 
>> Rob
>> 
>> On 08/10/2010 06:57 PM, Phil Harman wrote:
>>> Hi Rob,
>>> 
>>> I will look at that since it would solve the problem of FPGA pins. One
>>> other advantage of the Ethernet solution is that a 125MHz clock is all we
>>> need for the entire board.  We would need an additional 24MHz clock for
>>> the USB.
>>> 
>>> Jumper selecting some 20+ pins could also be a problem particularly since
>>> the PHY data is at 250MHz.
>>> 
>>> I've also had a chance to use the Ethernet connection to HPSDR for a few
>>> days.  It is so much nicer than USB. No driver issues, at Gig-E I can
>>> unplug all the cables (with the PC and OyzII still connected) and plug
>>> then back in and it all starts automatically.
>>> 
>>> 73's Phil...
>>> 
>>> 
>>> 
>>>    
>>>> Hi Phil,
>>>> 
>>>> Have you considered possibly having both circuits on the board, so that
>>>> one or the other could be selected with a set of physical jumpers to
>>>> connect the pins to the USB part or the ethernet part of the circuit?
>>>> 
>>>> 73,
>>>> 
>>>> Rob
>>>> 
>>>> On 08/05/2010 08:20 PM, Phil Harman wrote:
>>>>      
>>>>> Hi Rob,
>>>>> 
>>>>> I don't think we will have enough FPGA pins to have both options.
>>>>> 
>>>>> 73's Phil...
>>>>> 
>>>>> 
>>>>> 
>>>>>        
>>>>>> ***** High Performance Software Defined Radio Discussion List *****
>>>>>> 
>>>>>> Hi Phil,
>>>>>> 
>>>>>> I vote for ethernet as well, but I'm wondering how much it would add to
>>>>>> the complexity and cost to leave the USB interface on there as well.
>>>>>> 
>>>>>> 73,
>>>>>> 
>>>>>> Rob, KL7NA
>>>>>> 
>>>>>> On 08/04/2010 07:18 PM, David McQuate wrote:
>>>>>> 
>>>>>>          
>>>>>>> ***** High Performance Software Defined Radio Discussion List *****
>>>>>>> 
>>>>>>> I vote for Ethernet.  (I believe I heard you had a way of loading the
>>>>>>> FPGA over Ethernet. True?)
>>>>>>> 73,
>>>>>>> Dave
>>>>>>> 
>>>>>>> Phil Harman wrote:
>>>>>>> 
>>>>>>>            
>>>>>>>> ***** High Performance Software Defined Radio Discussion List *****
>>>>>>>> 
>>>>>>>> All,
>>>>>>>> 
>>>>>>>> Having completed the Beta testing of Hermes we are now preparing to
>>>>>>>> make
>>>>>>>> the necessary changes to bring the board into a production ready
>>>>>>>> state.
>>>>>>>> 
>>>>>>>> There are quite a few changes which are mainly due to the fact we
>>>>>>>> want to
>>>>>>>> ensure the product lives up to the 'High Performance' name tag.
>>>>>>>> 
>>>>>>>> One of the changes is to replace one of the high current linear
>>>>>>>> regulators
>>>>>>>> with a SMPSU. We are fortunate to have Kjell, LA2NI,  on our design
>>>>>>>> team.
>>>>>>>> Kjell has designed a high frequency SMPSU that works well when
>>>>>>>> incorporated on the Hermes PCB and does not introduce significant
>>>>>>>> spurs. This substantially reduces the current drain and also the heat
>>>>>>>> dissipation.
>>>>>>>> 
>>>>>>>> The other potential change is this.  I have this week build a
>>>>>>>> prototype
>>>>>>>> OzyII Gigabit Ethernet board. It works very well and I'm impressed
>>>>>>>> with
>>>>>>>> how rugged Ethernet appears to be in comparison to USB and Firewire.
>>>>>>>> 
>>>>>>>> We therefore have the opportunity to replace the USB interface on
>>>>>>>> Hermes
>>>>>>>> with Ethernet.  There are a number of advantages in doing this:
>>>>>>>> 
>>>>>>>> - we overcome the USB driver issues when using different operating
>>>>>>>> systems
>>>>>>>> - we can 'network attach' Hermes
>>>>>>>> - we will have a very high speed interface to the board for future
>>>>>>>> features
>>>>>>>> - we can use a much longer Ethernet cable than USB allows
>>>>>>>> 
>>>>>>>> the disadvantages
>>>>>>>> 
>>>>>>>> - it may need more that one spin of the PCB which will delay the
>>>>>>>> delivery
>>>>>>>> - we will use approximately 10% of the FPGA to implement the Ethernet
>>>>>>>> interface.
>>>>>>>> 
>>>>>>>> I'm not too concerned about using more of the FPGA since the device
>>>>>>>> we are
>>>>>>>> using is 70% larger than that used on Mercury.
>>>>>>>> 
>>>>>>>> So "to USB or not to USB - that is the question"?
>>>>>>>> 
>>>>>>>> 73's Phil...VK6APH
>>>>>>>> 
>>>>>>>> 
>>>>>>>> 
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>>>>>>>> 
>>>>>>>> 
>>>>>>>>           
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>>>>>>>            
>>>>>> --
>>>>>> Rob Frohne, Ph.D., P.E.
>>>>>> E.F. Cross School of Engineering
>>>>>> Walla Walla University
>>>>>> 100 SW 4th Street
>>>>>> College Place, WA 99324
>>>>>> (509) 527-2075    http://people.wallawalla.edu/~rob.frohne
>>>>>> 
>>>>>> _______________________________________________
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>>>>>> 
>>>>>>          
>>>>> 
>>>>>        
>>>> --
>>>> Rob Frohne, Ph.D., P.E.
>>>> E.F. Cross School of Engineering
>>>> Walla Walla University
>>>> 100 SW 4th Street
>>>> College Place, WA 99324
>>>> (509) 527-2075    http://people.wallawalla.edu/~rob.frohne
>>>> 
>>>> 
>>>>      
>>> 
>>>    
> 
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