On Sat, 24 Dec 2011 08:04:38 +0000 (UTC), Chuck Banshee
wrote:

This is my first time installing cat5 cable in my house and I am unsure
how to connect to RJ45 jacks that I need to put in the wall.

The basic idea is to build a "star" (also known as home run).
Everything comes to a central location, where you locate a 10/100baseT
ethernet switch. You can add additional ethernet switches at any
endpoint that needs more than one connection (forming a "tree").

I've installed a WISP antenna 75 feet from the house & will be routing
the outdoor cat5 cable into the middle of the house (another 25 or so
feet) -

Very vague. What manner of hardware are you installing? Most WISP
system use PoE to the radio/antenna on the roof, and ethernet to some
manner of power injector. From there, you run ethernet to a local
router, and then to the central ethernet switch. The router might be
built into your unspecified model WISP radio. Note that I said
"switch", not "hub". You do not want a hub.

Hopefully, you didn't run 75ft of coaxial cable between the radio and
the antenna. That's much too long. Cable losses at 2.4GHz are quite
high.

Pictured here is what I have in the wall in the middle of the house:
http://picturepush.com/public/7212874

My Zircon stud sensor sorta works. However, I cheat. I have photos
of what's inside my walls from before the drywall and paneling was
added.

While it's nice to have the outlet box attached to a stud, it's not
necessary. There are rework PVC device boxes, that attach to the
drywall.

RJ45 jacks do not cause loss. Un-connected jacks do not cause loss.
Unterminated cables do not cause loss. The catch is that you have to
install one cable for each RJ45 jack. Since CAT5e has 4 pairs of
wires, and ethernet uses only 2 pairs, you can split the cable pairs
and wire two jacks on the wall jacks, and attach two RJ45 plugs at the
other end of the cable. However, if you're using PoE on this segment,
you'll need all 4 pairs to the wall jack.

Since you're running CAT5 through the wall base plate, you'll need to
drill a large enough hole to accommodate the number of cables you
need. If you only want to run one cable, then perhaps adding an
ethernet switch near the wall plate might be easier.

I'm not sure if it's best to route the wire all the way from the antenna
to the middle of the house (about 75 feet to the house and another 25 or
30 feet zig-zagging to the crawl space and then up to the newly drilled
hole at the wall).

Hint:
a "wire" is a single length of insulated copper.
a "cable" is a collection of wires enclosed by a vinyl jacket.

Hopefully, this cable is CAT5e. It will need to run from the rooftop
mast, to the nearest convenient location that has AC power (for PoE).
That's usually also the location of the central ethernet switch.

I'm going to put a wall plate at the wall in the middle of the house; but
should I also put a wall plate where the wire enters the house?

No. Wall plates are NOT waterproof. You should use a proper cable
entry. For rooftops, that's a "rams head". For wall entry, cable
entry with a drip loop. There are some tricks involved (such as
slightly angling the hole in the wall upward so accumulated water
drips outward). Also, leave a service loop for anything that you
install in the wall. Talk to a DBS satellite dish installer for
clues.

Does breaking the line into sections degrade the signal?

Nope, as long as there is an ethernet switch between each segment.
However, if you're talking about running multiple segments and just
splicing them together, that also works. I suggest you terminate each
end with an RJ45 plug, and use a coupler to make the connection. It's
a bit more complex, but much easier to troubleshoot when the kids,
puppy, or mice, chew up the cable.
http://www.ebay.com/itm/260915346939

If I do put a wall plate at the entrance to the house, I'll likely put
the POE (power over ethernet) at the wall inside the house (otherwise it
will go in the middle of the house next to the WRT54G router).

Do NOT hide anything INSIDE the wall. One little spark or overheated
power device, and you'll have a fire in an inaccessible location.

When I put a wall plate in the middle of the house, would you add a
second female jack (just in case for future use?). Or does that also
degrade the signal?

Yes. As long as the 2nd jack is on a separate CAT5e cable, there's no
deterioration in the signal. The problem is that there's NEVER enough
ethernet wall jacks. If you expect that you'll need one, then install
two. If you think you'll need two, then install four. 6 jacks is
about the limit. Extra cable is cheaper than the time to do it over
again.

There are also ethernet switches that will fit in the wall, but you
won't like the price:
http://www.amazon.com/3CNJ220-CRM-4-Port-100Mbps-Ethernet-Switch/dp/B0001DHE0U

In summary, I'm not sure if I should strive to keep the line intact and
how I should terminate it.

Any advice?

I think you're over your head a little. Best to Google the internet
for CAT5 and ethernet installation instructions and examples. Also,
talk to a professional cable installer before you make a major
mistake. The danger is that if you have a house fire, and the fire
inspector finds non-code compliant creative wiring, you run the risk
of having your insurance company declare that you were the cause of
the fire.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558