[TechAssist] Re: Fw: Are onidirectional antennas any good(roof)
- From: "Damon" <damoneb@xxxxxxxxxxx>
- To: <techassist@xxxxxxxxxxxxx>
- Date: Thu, 15 Sep 2005 19:57:45 -0500
Darn, couldn't get on your FTP site at 8:00 pm CST. Couldn't get on your
Http site either.....probably one of those crappy spybots redirecting
me.....
Damon B
Telrad Electronics
Fort Wayne IN
----- Original Message -----
From: "Wayne Vanaman" <Wayne@xxxxxxxxxxxxxxxxxxxxx>
To: <techassist@xxxxxxxxxxxxx>
Sent: Thursday, September 15, 2005 4:24 PM
Subject: [TechAssist] Re: Fw: Are onidirectional antennas any good(roof)
> Hey, I provide all the insight I can.
>
> Picture a square wave.
> With a digital transmission the entire 6MHz bandwidth transmission,
> viewed on a spectrum analyzer, would, ideally be similar in shape, were
> the analog transmission is a halversine waveform. If some portion of
> the transmission is greater or lesser amplitude you will have distortion
> to some degree.
>
> If the transmission amplitude is very low, almost "in the grass", the
> noise floor, but the shape is good, you would probably have a good signal.
>
> If the transmission amplitude is high but the bandwidth is distorted,
> the data is confused and you will not have a usable signal.
>
> I had a spectrum analyzer in here for a while. Local channels in the
> thousands of microvolts, but with distorted wave forms could not be
> viewed on my TV, while there were channels 40dB down, with good even
> bandwidth that never showed signal breakup.
>
> Short of using a spectrum analyzer to aim the antenna it is pretty much
> a guess. Trees that cause ghosts in analog attenuate or distort
> portions of the signal so that the signal becomes unusable.
>
> Out in an open field a dipole should be good. In reality, my house is
> surrounded by trees.
>
> Look here:
> ftp://pensacolatvrepair.com/pub/IMAG0002.JPG
> I know, I know, pic stinks. What you see are analog and digital
> stations. Notice that none of the digital stations have a flat top.
> Not good. Guessing 'cause I don't remember for sure, you are looking
> at, left to right, channel 17, digital, 19, 21, 23, 27 digital, 31
> digital. Channel 17 I always get well. Chs 19 and 21 are snowy but
> watchable, channel 27 frequently breaks up. Notice the leading edge.
> Channel 31 is always good.
>
>
> Wayne Vanaman
> Omega Electronics
> 6904 W Fairfield Dr
> Pensacola, Fl. 32506-3310
>
> Wayne@xxxxxxxxxxxxxxxxxxxxx
> WWW.PensacolaTVRepair.Com
>
> 850-456-5995 voice
> 850-458-6369 fax
>
>
> AL LEATHERMAN wrote:
> > Thanks Wayne, but does this mean we have to aim the antenna at the
station,
> > for digital.?
> >
> > Al's TV
> > Mine Hill, NJ. 07803
> > 972-361-5796
> > WWW.ALS-TV.NET
> > ----- Original Message -----
> > From: "Wayne Vanaman" <Wayne@xxxxxxxxxxxxxxxxxxxxx>
> > To: <techassist@xxxxxxxxxxxxx>
> > Sent: Thursday, September 15, 2005 3:27 PM
> > Subject: [TechAssist] Re: Fw: Are onidirectional antennas any good(roof)
> >
> >
> >
> >>RF emissions are not directional. The transmitting antenna on the other
> >>hand...
> >>
> >>Wayne Vanaman
> >>Omega Electronics
> >>6904 W Fairfield Dr
> >>Pensacola, Fl. 32506-3310
> >>
> >>Wayne@xxxxxxxxxxxxxxxxxxxxx
> >>WWW.PensacolaTVRepair.Com
> >>
> >>850-456-5995 voice
> >>850-458-6369 fax
> >>
> >>
> >>AL LEATHERMAN wrote:
> >>
> >>>Thajnks Damon!
> >>> NOW: Does anybody know if digital is highly directional? I would
say
> >>>no,but what do I know?
> >>>
> >>>Al's TV
> >>>Mine Hill, NJ. 07803
> >>>972-361-5796
> >>>WWW.ALS-TV.NET
> >>>----- Original Message -----
> >>>From: "Damon" <damoneb@xxxxxxxxxxx>
> >>>To: <techassist@xxxxxxxxxxxxx>
> >>>Sent: Thursday, September 15, 2005 6:03 AM
> >>>Subject: [TechAssist] Re: Fw: Are onidirectional antennas any
good(roof)
> >>>
> >>>
> >>>
> >>>
> >>>>For those "Philly" stations consider a Yagi or Parabolic.....generally
> >>>>the
> >>>>gain on those are 7 to 10 db....look up "Yagi Parabolic antenna gain"
on
> >>>>Google. The Yagi is highly directional....normally has a 15 degree
lobe
> >>>>for
> >>>>reception, great if you have all your TV stations located on the same
> >>>>side
> >>>>of town like Fort Wayne does......
> >>>>Helps to limit reflections in closer areas...but with Digital
> >>>>transmission
> >>>>does that really matter?
> >>>>
> >>>>Damon B
> >>>>Telrad Electronics
> >>>>Fort Wayne IN
> >>>>----- Original Message -----
> >>>>From: "AL LEATHERMAN" <alleathe@xxxxxxxxxxx>
> >>>>To: <techassist@xxxxxxxxxxxxx>
> >>>>Sent: Wednesday, September 14, 2005 2:13 AM
> >>>>Subject: [TechAssist] Re: Fw: Are onidirectional antennas any
good(roof)
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>>Thanks Al.
> >>>>>
> >>>>>Al's TV
> >>>>>Mine Hill, NJ. 07803
> >>>>>972-361-5796
> >>>>>WWW.ALS-TV.NET
> >>>>>----- Original Message -----
> >>>>>From: "Al Gutz" <alg@xxxxxxxxxxx>
> >>>>>To: <techassist@xxxxxxxxxxxxx>
> >>>>>Sent: Tuesday, September 13, 2005 9:31 PM
> >>>>>Subject: [TechAssist] Re: Fw: Are onidirectional antennas any
good(roof)
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>>>Al
> >>>>>>When talking antenna gain omni is still a joke. If it has good
> >>>>>>compression of vert lobe you may get a 1 or 2 db gain, about the
same
> >>>>>>as
> >>>>>>a rabbit ears mounted on the roof.
> >>>>>>If you are going basicly 2 directions use a low gain for closer
stuff
> >>>>>>and higher gain for longer haul, join with a coupler. If looking for
> >>>>>>stations in several directions look at a rotor.
> >>>>>>
> >>>>>>Al G
> >>>>>>
> >>>>>>AL LEATHERMAN wrote:
> >>>>>>
> >>>>>>
> >>>>>>>Sent: Tuesday, September 13, 2005 10:45 AM
> >>>>>>>Subject: Are onidirectional antennas any good(roof)
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>>Omnidirectional used to be a joke, a bad one.Has technology
> >>>>>>>>improved,as
> >>>>
> >>>>I
> >>>>
> >>>>
> >>>>>>>>am 35 miles from NYC,about 90 miles from Philly. Sounds too good
to
> >>>>>>>>be
> >>>>>>>>true. al L
> >>>>>>>>
> >>>>>>>>Al's TV
> >>>>>>>>Mine Hill, NJ. 07803
> >>>>>>>>972-361-5796
> >>>>>>>>WWW.ALS-TV.NET
> >>>>>>>
> >>>>>>>
>
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