Topband: Light fiber question

[Tom W8JI]

People forget, or don't know, fiber cables require modulators and 
demodulators. The modulators and demodulators are not simple, and have 
horrible dynamic range compared to a simple piece of coax.

I can't think of a good Ham shack application using fiberoptics for coupling 
RF signals. First, the dynamic range stinks compared to coax. Second, common 
mode is very easily completely cured with extreme measures.

I feel a little guilty about starting some of the common mode stuff, because 
it has taken off into being far more extreme than it really needs to be. As 
a general rule, if you isolate the antenna end and have a proper shack 
entrance, a few beads are the most you'll need.

One of the worse things are plastic boxes and wire grounds inside insulated 
boxes, and what we do on antenna with poor grounds. But it is all easily 
fixed without extreme measures.







----- Original Message ----- 
From: "Shoppa, Tim" <tshoppa at wmata.com>
To: "Bruce" <k1fz at myfairpoint.net>; <topband at contesting.com>
Sent: Thursday, October 24, 2013 9:29 AM
Subject: Re: Topband: Light fiber question


>I do not know of any analog optical coupling technology that has nearly the 
>dynamic range of copper.
>
> 50dB is considered quite good HF dynamic range for completely sealed 
> analog optocouplers. Start putting cables and junctions in there and it 
> has to only get worse.
>
> Tim N3QE
>
>
> -----Original Message-----
> From: Topband [mailto:topband-bounces at contesting.com] On Behalf Of Bruce
> Sent: Thursday, October 24, 2013 12:06 PM
> To: topband at contesting.com
> Subject: Topband: Light fiber question
>
>
>
> Tim,
> Good information, but I was thinking of a way for "Mr. Average DXer" to 
> get  a connection, that is not adding noise, from his on site receiving 
> antenna.
>
> 73
> Bruce
>
> ----- Original Message -----
> From: "Shoppa, Tim" <tshoppa at wmata.com>
> To: "Bruce" <k1fz at myfairpoint.net>
> Sent: Thursday, October 24, 2013 5:50 AM
> Subject: RE: Topband: Light fiber question
>
>
> I think that is called "a remote receiver connected by optical fiber
> networking". Several folks use this technology on topband. Sometimes the
> remote receiver is the other side of the world.
>
> Tim.
> -----Original Message-----
> From: Topband [mailto:topband-bounces at contesting.com] On Behalf Of Bruce
> Sent: Thursday, October 24, 2013 11:48 AM
> To: topband at contesting.com
> Subject: Topband: Light fiber question
>
> I am now using twisted pair on my receiving Delta antenna and is less
> noise than the coax.
>
> Question: Any one ever tried using light fibers as a near ultimate
> transmission line from their receiving antennas?
>
> 73
> Bruce-K1FZ
> www.qsl.net/k1fz/beveragenotes.html
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