[CQ-Contest] Cable modem questions

[Gary J. Ferdinand]

Bob,

You have more options.

First of all, you do not NEED a router. You might decide it's the best
option, but it's not necessary.

I would add these additional options...

3.  Add a hub.  Put the hub in a convenient location.  Route a Cat 5
ethernet cable from each computer to that hub.

4.  Kiss off both the router idea and the hub if you don't mind using some
older technology.  Use 10Base2 ethernet:  RG59/U coax to a BNC connector on
the ethernet card (you need to buy an ethernet card that is either a combo
or a BNC-only card) on each computer.  The computers basically are wired
together.  At each computer you have a BNC Tee connector, the unused port of
which has a BNC terminating plug on it.   10Base2 networks have as a
disadvantage a speed limit of 10Mbps, which is still plenty fast enough for
your broadband connection at 765K.


I use both cat5 and the RG59 versions in the shack. 3 computers tied with
10base2 and another with the 3 via a hub and cat5.  I don't run legal limit,
being constrained by my SB220, but still around a KW or so.  Not a peep of
RFI among the network of 4 computers ALL in the ham shack within 20 ft of
the rig.  Total RG59 coax length/cat5 around 50 ft or so. (I have lots of
excess cable using prepared lengths).  Of those in my geographic area that I
know use LANs, none has experienced any RFI on ethernet lines, so I conclude
that it is uncommon and you should NOT expect a problem.

With options 1 thru 4 you will use file/printer sharing of Win98 along with
Win98's Internet Connection Sharing (ICS), I presume, so that both 'puters
will access each other and the internet. Since ICS maps the "remote"
computer address to that of the internet-connected computer, your ISP is
generally unaware that the sharing is going on.  Two ISP accounts are not
required.  The zone alarm you use today with your broadband link will still
work in an ICS LAN configuration and if you only access the internet thru
the ICS gateway, will not be required on the "remote" computer any longer.
You didn't state what program you are using to act as the PPPoE client on
the Dell (the pgm that talks thru the ethernet card to the external modem).
But, if you decide to use ICS to allow sharing of the broadband connection
with the downstairs computer, you might run into some complexity with the
(lack of) PPPoE/ICS support in Win98.  I ended up installed RASPPPOE, a
freeware program, and kissing off my ISP's PPPoE application to make the
sharing work.  RASPPPOE is highly thought of, BTW.

As for interception of the radiated wireless signals, I see no way zone
alarm can be of assistance there.

I've never tried wireless LANs and will read this thread with interest to
see others' experiences vis-a-vis RFI.

GL/73,

Gary W2CS



> -----Original Message-----
> From: cq-contest-admin at contesting.com
> [mailto:cq-contest-admin at contesting.com]On Behalf Of Robert Shohet
> Sent: Sunday, March 10, 2002 11:22 AM
> To: cq-contest at contesting.com
> Subject: [CQ-Contest] Cable modem questions
>
>
> Hi Guys,
>
> I currently use the basic Ethernet card with a Motorola SB4100
> Modem to get
> Charter Pipeline service (about 750k bandwith) to my Dell Win98 computer.
>
> I would like to network this computer with another Win98 computer in the
> shack (downstairs and about 50 feet away).
>
> I was told that I have two basic options:
>
>  1) Buy a router (about $90 at Staples) and about 50' of Category 5 cable
> together with another Ethernet card and Motorola Modem SB4100
> modem and then
> install and hook everything up (and hope that it works).
>
> 2) Buy a wireless router (about $150) and Two high end Ethernet
> cards (about
> $100) and the Motorola modem and then install same.
>
> I am wondering about the potential issues for each....
>
> For Scenario #1, by far the simplest, I wonder about the degradation of
> signal over 50' of category 5 cable to the upstairs computer.  I
> also wonder
> about the potential RFI problem of transmitting legal limit power
> and having
> the 50' cable run act as an antenna.  I know that I can use
> ferrite beads to
> reduce the effects of RFI but I still wonder about the signal degradation
> over such a long length of cable.
>
>  What about the RFI to the router located 10' away from the
> transmitter.  Is
> this an issue that anyone has in their station?  If so, how is it solved?
>
> Scenario #2
>
> If  I go wireless, will the legal limit RF create a problem with
> the router
> and the wireless signals?
>
> Also, if there is a wireless signal now, wouldn't it be easy for anyone in
> close proximity to my qth to access either or both computers and get data
> from my files?  Security is a real concern to me.
>
> I currently use Zonealarm ver 2.6 as a firewall on both computers but my
> understanding is that this is excellent protection against people
> trying to
> invade from the "outside"  but I don't know if it will protect against
> invasions against interecepted wireless signals and my
> transmissions by the
> wireless router.
>
> Can anyone provide practical info on these issues?
>
> Many thanks in advance for your help.
>
> 73
>
> Bob KQ2M
>
>
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