[Coco] Coco MC-10 connection problem

[gene heskett]

On Thursday, December 22, 2011 07:47:51 PM J.P. Samson did opine:

> On Dec. 22, 2011, at 4:28 PM, john T Chasteen wrote:
> > I have the impression that I need the "Channel 3/4 Switch" to connect
> > the MC-10 to the New Flat screen TV.  Will the MC-10 work when
> > connected directly? I have several inputs to the TV... TV, VGA,
> > SVIDEO, HDMI, AV, COMPONENT The MC-10 Manual instructs to use the use
> > the Switch... The MC-10 can be set to connect to channel 3 or 4 .
> 
> Doesn't the MC-10 have a channel selector switch on the bottom of the
> computer?  Assuming your new TV has an analog tuner in it, I figure
> you should be able to connect to the coax input on the TV directly
> (using the aforementioned adapter).  Then, simply set the channel on
> the TV to 3 or 4 to match the switch setting on the underside of the
> MC-10.  As far as I know, there aren't any impedance-matching issues
> (everything is at 75 ohms, I think).  The big problem is how much
> interference will there be in the picture?
> 
> Any modern TV is not going to have a twin-lead 300 ohm antenna input,
> so why bother trying to convert the MC-10's 75 ohm RF output using the
> switchbox, only to have to reconvert back to a 75 ohm coax cable to
> screw into the coax jack on the back of the TV?
> 
> Perhaps this is more complicated that I think.  (Could there be a
> balanced versus unbalanced issue?)  Gene knows way, way more about
> this stuff.
> 
> -- JP
> 
IIRC the coco2 had an rf that was fed to a phono jack, so all this needs, 
since the tv's input can likely be switched to various inputs by the remote 
control they all have now, and that removes the requirement for a switch in 
the external world between the coco and the monitor.

So all he likely needs is a decent length of (prefereably quad shielded 
RG-59 or clone) rf cable, with the F-59 on one end of it, and the last I 
looked, the shack had some sort of a "Cambridge" connector that screws 
itself onto the cable after the end of the cable has been stripped to the 
correct lengths, and which has a male phono plug format on the end.  So the 
F-59 gets screwed to the monitor, and when the coco is brought out, the 
male phono plug is plugged into the coco.  Both of these "Cambridge" 
connectors s/b available at the shack.  I expect the cable can be had too, 
probably in 10 or 25 foot lengths.  Any ready-made cables they might have 
are probably made using the absolute cheapest cable that still has 
continuity, so I'd make my own just for the shielding assurances.

Clark Wire & Cables type 7559 would be the best, its shielding is about 110 
db effective, and its amazingly flexible when compared to any other rg-59 
cable I have ever handled.

Be aware that Cambridge style screw on connectors, while handier than 
sliced bread or bottled beer, will also need 1/4 turn of tightening about 
annually because the connection pressure for the shielding is dependent on 
how hard the plastic of the cables insulation pushes back & the cable 
slowly crushes, loosening the connections.  For that reason, in broadcast, 
we don't use them for anything that must still be working a year down the 
road, we'll use the 2/3rds less expensive and far more time consuming to 
install crimp on versions.
 
> > On Thu, 22 Dec 2011 14:50:09 -0700 "J.P. Samson"
> > 
> > <coco+list at jeanpaulsamson.com> writes:
> >> Perhaps something like this F-jack adapter connected to an RCA cable
> >> would be one way to bypass that "Channel 3/4" switchbox entirely:
> >> http://www.radioshack.com/product/index.jsp?productId=2103471
> 
> --
> Coco mailing list
> Coco at maltedmedia.com
> http://five.pairlist.net/mailman/listinfo/coco


Cheers, Gene
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