Re: Multiswitches and Multisatellite Dishes

[Ian Shef <invalid@xxxxxxxxxxxxx>]

Lewis Gardner <lgardner@xxxxxxxxxxxxxxxxxxxxxxxxxx> wrote in
news:453e885c$1_1@xxxxxxxxxxxxxx:

> Ian Shef wrote:
>
>> I was under the impression (right? wrong?) that each satellite
>> transponder transmits on both of two possible polarizations.  If so,
>> then my triple LNB dish actually receives 6 "signals" (3 satellites x 2
>> polarizations) and only provides 4 of these 6 at a time.
>
> Correct.
Thanks, although further research suggests that maybe only one LNB operates
with polarization.  (See below)
>
>
>> In this case, a multiswitch helps but doesn't completely solve
>> anything.
>
> That is because there is a switch built into the feedhorn/LNB assembly.
>
I saw a suggestion someplace to bypass the builtin switch.  Sounds risky.
>
>> What solutions are available?
>
> If you can find 3 discrete feedhorn/LNB assemblys that will fit in place
> of the current feedhorn/LNB/switch assembly then you can add a switch.

Sounds like a long shot.
>
> You need a 6x6 switch. 6 cables from the 3 dual polarity LNBs then 5
> cables to your receivers (2 each to the DVRs and 1 to the single tuner
> receiver).
Yes.
>
> A quick google yielded the Zinwell WB68 6X8 Multiswitch. There might be
> a better option but I didn't investigate further.
>
> Here is a link:
> http://store.high-techoffice.com/ziwb6x8mudia.html
>
> Looks like a decent FAQ:
> http://store.high-techoffice.com/samu.html

Your links also led me to:
http://store.high-techoffice.com/eaasdtdi4mu.html

which shows a Phase III (triple LNB) dish hooked to a multiswitch.  It is
my newfound understanding that the Phase III dish is what I have.  If this
diagram is right, then either:
1)  Only one of the three satellites makes use of polarization, or
2)  There is some other sharing scheme being used, such as frequency
division.

As far as I know, a change in DC voltage along with the presence or absence
of 22 KHz (see, I have done additional research in the meantime) are the
common way of switching inputs.  This also suggests that there are really
only 4 inputs (not 6) available.
>
> The usual disclaimers apply, I know NOTHING about the seller...
>
> Good luck
>
>
> PS...
> Multiswitches with an odd number on the left side of the "x" (the input
> count) diplex a over the air (OTA) antenna (1 signal) with the "x"-1
> satellite signal so you can get satellite and OTA local TV on the same
> coax.
... as long as another diplexer is used at each receiver as well.  I just
learned about this during my research as well.

Thanks very much for your information.

There are a few sites that provide information about using multiswitches
with single and with dual LNBs, along with an explanation.
There are also a few sites that show how to hook up a 4 input multiswitch
to a Phase III DirecTV antenna.
However, I haven't yet found a site that explains HOW a 4 input multiswitch
can work with a Phase III DirecTV antenna.

I guess that I could just accept it on faith that it works, but I would
prefer to know the details.



--
Ian Shef     805/F6      *    These are my personal opinions
Raytheon Company         *    and not those of my employer.
PO Box 11337             *
Tucson, AZ 85734-1337    *