[hpsdr] VK6APH de DL1EHU: Metis (formerly called Ozy II) - interface module - suggestion of SFP-IF

[Jeremy McDermond]

On Mar 24, 2011, at 5:42 AM, ludwig jaffe wrote:

> ***** High Performance Software Defined Radio Discussion List *****
> 
> Dear VK6APH,
>  
> your Metis is quite fine, but for EMC reasons I will like to have a gbit fiber to the TRX.
>  
> So lets have an SFP-Port instead of a copper ethernet with phy. Depending on the needs the
> user can plug in a copper interface gbit ethernet, or a fiber gbic for multimode or single mode fiber.
>  
> I plan to put a TRX-Box with all the stuff near the antenna and simply route a fiber and AC to the mast.
>  
> I hope you agree and change the design, or make a variant with additional SFP-Port.

I'm not sure how practical that is.  Having the standard design be SFP-only would increase the cost significantly.  You're replacing a < $10 PHY chip with a $60-$70 copper SFP.  While fiber SFPs are cheap, coper ones are expensive because nobody uses them.  The thought is "why should I waste an SFP slot with a copper port when I have 48 fixed gig ports on this switch."

Having a variant with an SFP is an interesting idea, but given that the costs of copper SFPs are expensive enough to preclude making it the standard configuration, I wonder how much demand there would be considering the work it would take to come up with it.  The board would have to be completely redone since the SFP cage is going to be half the width of the card.  a lot of circuitry would have to be moved around to do so.  Additionally, you'd need to add a laser management chip like the MIC3001, which isn't available in a leaded package.

Don't get me wrong, I think it's a great idea in theory.  It'd certainly make fiber installs a lot easier.  But, given the demand and the challenges, I think the real answer is just getting a fiber/copper media converter.  Amazon has a SFP->copper converter for $25.

http://www.amazon.com/TP-Link-MC220L-1000Base-LX-1000Base-SX-1000Base-LH/dp/B003H44S40

>  Vy73 de dl1ehu

--
Jeremy McDermond (NH6Z)
Xenotropic Systems
mcdermj at xenotropic.com




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