Text 74, 105 rader
Skriven 2005-07-15 13:50:34 av Sean Dennis (1:18/200)
     Kommentar till en text av Herman Trivilino
Ärende: Re: FM Capture Card
===========================
Herman,

I'm really enjoying this conversation: it's nice to see some traffic
in here. :)

 HT> Mine is AVerTV GO 007 FM Plus.  I'll open the case and see if I can
 HT> find a "shield".

Most of them do have one over the main receiving circuitry-mine looked
a little like this:

- | | | | | -
- XXXXXXXXX -
- | | | | | -

Where the | and - are pins going into the main PCI board, soldered in
and directly grounded.

 HT> Hmmm...  I would think the power supply would be grounded via the
 HT> screws that mount it to the case.  Is there a grounding cable?  If
 HT> not, do you think installing one might help?

The screws and the cable being plugged into the wall.  Check the
ground in your socket too.  Most homes aren't grounded as well as they
should be.  A grounding cable certainly couldn't hurt!  For my ham
radio stuff, I have a nice big, thick braided cable attached to a
copper rod driven about five feet into the ground. :)

 HT> Let's see if I can explain it this way.  The FM antenna is a "T" shape.

All the ones I've seen for my use are "T"-shaped also, but look like:


*------++------*
       ||
       ||

The * are just little plastic ends on the wire.  You hang the wire on
the wall like a giant T on the wall.  I've generally had the best
reception with those myself, but as always, YMMV. <G>

 HT> Any FM antenna I've ever bought or made doesn't terminate at the ends
 HT> of the "T".  The wires turn 180 degrees back on themselves and join
 HT> where the base of the "T" meets the top.  Such an antenna passes a
 HT> continuity test.

I've seen the FM loops, but never used one.  To be very honest, I'm
not sure of the big difference and now my curiosity gets me.  The
reason why I'm wondering is that I've got a 5/8-wavelength antenna on
my car (a stainless steel whip with a load to get a 3dB gain) for my 2
meter radio inside (2 meter, if anyone doesn't know, covers
144-148Mhz - it's line-of-sight FM).  The whip does wonders and it's
the closest thing to a T-antenna that I have for FM.

I'm wondering what the loop would do-be better grounded?

 HT> I think you recomended a length of 16 ft.  This would be the length of
 HT> the top op the "T", right?  Do you recommend any type of wire?  Should
 HT> a sheilded cable be used to form the base of the "T"?

I've just used good ol' 16-gauge speaker wire from Radio Shack,
believe it or not.  Of course, this is in a room without a big RFI
generator (read: computer :) in it.  You might try wrapping the
connection in copper tape for shielding if it's the old screw-type or
a good shielded connector too.

 HT> That's an attidtude I love to see.  I try to soak up knowledge like a
 HT> sponge, myself.  I teach physics at a community college and enjoy
 HT> learning more, I think, than most of my students.

Hee!  Well, believe it or not, I was wanting to teach physics at one
time.  Now I'm 32, have a marriage behind me, a short career in the
Army and the rest of my life in front of me.  I'm planning on once we
move (we're moving to Johnson City, TN on the 20th and East Tennessee
State University is about a five min drive down the road) and
establish residency to go back to school at night.

All of those years in the Army gave me about $17,000 and some
change for school, so I'd better use it while I can (I lose it in
2008).  I learned to read at a very early age and was reading the L.A.
Times at the age of three.  My thirst for knowledge has gotten me into
hot water (a la taking things apart and not putting them back together
just right ;), but it's never-ending.

I'm still constantly learning about computers and ham radio.  In fact,
I got quite the physics lesson the other day reading about wave
propagation and working with oscilliscopes.  That was very enjoyable.
I'm currently a Technician-class ham, but working on my General class
license.

As for loving to learn more than your students, I can heartily agree
with you on that-it's only now, when I'm a little more mature and
settled, that I realize what a gift higher education is and how
wonderful it is to learn.

Now if I can just learn to work on computers and not release the smoke
they run on every so often, I'll be good. <G>

Later,
Sean

 

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