[hpsdr] Hermes

[Ahti Aintila]

Lyle, All,

In my case and in my hamshack it is very difficult to avoid
groundloops between the computer, SDR hardware, power amplifiers and
the antenna grounding. With 7 years experience with SDR-1000 and
unisolated USB the connection seems to be sensitive to common mode
interferences coming from mains power transients and induced RF power.
As a result the USB communication stalls now and then, and the system
has to be rebooted to get it functioning again.

That is a nuisance, especially in my 24/7 Faros monitoring system.
Isolated Ethernet possibly would correct the situation. For the most
common applications of Hermes, 100 MHz Ethernet should be fast enough,
but I have nothing against 1 GHz.

Ahti OH2RZ

On 5 August 2010 21:19, Lyle Johnson <kk7p at wavecable.com> wrote:
> ***** High Performance Software Defined Radio Discussion List *****
>
>  On 8/5/10 10:55 AM, Dick Faust wrote:
>>
>> ***** High Performance Software Defined Radio Discussion List *****
>>
>> Lots of discussion so here is my 2 cents worth.
>>
>> I would go with Ethernet if the noise level can be controlled to an
>> acceptable level.  I agree it would be nice if the USB-2 interface could
>> remain and what about USB-3  which is just coming out.
>
> Hermes is a small system, not an expandable experimenter's system like
> Atlas-based modules.
>
> I prefer USB2 and forgo Ethernet on Hermes for the moment.
>
> A Gig-E-based Hermes can always be developed later.  USB2 is here, it works,
> noise is manageable, software exists and runs...  ALl we need is the release
> of workign hardware designs including PCB and we;re already good to go.
>
>> ...
>>
>> I also think support for 10-100-1000 speeds whether automatic or by jumper
>> should be available.
>
> 10 megabit Ethernet is too slow for much of anything with streaming audio.
>  USB 1.1 is limited for the same reasons.  OK for an endpoint, but probably
> not terribly useful for the data source 9Hermes).
>
> 100 megabit Ethernet also has much less bandwidth than USB2, but supporting
> it makes sense for low bandwidth applications.
>
> Just random thoughts,
>
> Lyle KK7P
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