[ivtv-users] cx18 scan does not pick up specific channel (HVR1600)

[Nick Nobody]

On May 9, 2009 01:26:31 pm Andy Walls wrote:
> On Sat, 2009-05-09 at 11:34 -0400, Nick Nobody wrote:
> > Sorry, I wasn't very clear in my sleepy state.
> >
> > Right now I have one length of wire that comes down from the antenna
> > (which is on a mast above my roof) and gets terminated inside the house
> > to something like this: http://imgur.com/JG0L.jpg
> >
> > >From there I either connect the television or the capture card, never
> > > both at
> >
> > the same time as that would be impossible :P
>
> Ah, OK.  moving on...
>
> > > This is the joy of digital TV reception that the FCC did not convey top
> > > the public.  :(  The FCC didn't fully assess the impacts to OTA
> > > broadcast to outlying areas either, I suspect.  What does
> > >
> > > http://www.antennaweb.org
> > >
> > > say you can expect for digital reception of WFFF at your location? 
> > > What is the bearing that antennaweb.org say you should point you
> > > antenna vs the bearing at which you have it? (antennaweb uses magnetic
> > > north) Antennaweb should be running a Longley-Rice propagation model to
> > > give you some decent expectation of availability.
> >
> > Sadly I can't use that because I don't live in the US. I tried entering
> > my coordinates and it only lists two stations from Plattsburgh. One at
> > heading 201 (WCFE) and the other at heading 188 (WWBI).
>
> Right.  And antenna web is probably running a link margin with the
> Longley-Rice Irregular Terrrain Model (ITM) with (I'm guessing) a 95%
> (or greater) availability.  Those were the only two stations, under
> antennaweb's assumptions about your setup, that have that availability
> year round.
>
> >  The WFFF transmitter is
> > southeast of me, I'd estimate the heading to be about 150 degrees and the
> > distance (using google maps) is about 142km (~88mi) "as the crow flies".
> >
> > This may seem far, but there are 3 other transmitters in that area that
> > I'm able to get great signal from (WCAX, WPTZ and WETK).
>
> For all four of those stations don't count on > 95% availability year
> round.
>
> > > Weather fronts and temperature varaition betwenn you and the
> > > transmitting station also make a difference at times.
> >
> > Sure enough, as soon as the sun comes out, "scan" no longer finds the
> > channel nor will gnutv get a lock on the signal.
>
> Wait until the sun is higher in the sky, and not in any of the beams
> (main lobe nor side lobe) of your antenna.  Reception might improve as
> long as your antenna isn't pointing at the Milky Way at that time.
>
> the time window when the Sun is not in your antenna beam might not be
> many hours of the day at a northern latitude pointing southward...
>
> > So it looks like my only option is to try out a pre-amp, I'll see if I
> > can find one around here at a reasonable price.
>
> Avoid units from Radio Shack, any unit that doesn't have a noise figure
> stated, or units with a noise figure over 3 dB.
>
> The companies in the US that come to mind are: Winegard (Indiana?),
> Channel Master (North Carolina?), and there's one up in new England
> somewhere (IIRC).  I found looking at various electronics stores to be a
> waste of time; I ordered via the internet.
>
>
> Good luck.
>
> Regards,
> Andy
>
>

I set up my mythbox tonight and will be testing it over the upcoming weeks. If 
need be, I'll get a pre-amp (I found a local shop that sells the Winegard one 
that you mentioned previously).

Thanks for all your help and your wonderfully detailed explanations,

nick