[TechAssist] Re: Fw: Are onidirectional antennas any good(roof)

  • From: Al Gutz <alg@xxxxxxxxxxx>
  • To: techassist@xxxxxxxxxxxxx
  • Date: Fri, 16 Sep 2005 22:24:25 -0400

Most TV and FM stations want a 360 deg horz pattern but signal that goes 
up in the air and down into ground is of no value. Transmitting antennas 
are designed to narrow the vert width of the pattern. By doing this a 
transmitting antenna can be omni horz plane and still get 3 to 5 db. 
gain. This is very useful, if you are allowed a effectiv radiated power 
of say 100Kw you only have to send maybe 15 or 20Kw u p to the antenna. 
On multi antenna towers the guy with the top position can design the 
highest gain antenna.

Al G

Damon wrote:
> I doubt digital is highly directional.....think about it.. TV stations want
> to transmit in ALL directions, yet have the capability of controlling their
> area of coverage too...
> Since the tranmission frequency is essentially unchanged as is the type of
> carrier...it's still a Sine Wave, it should essentially transmit the same as
> it did before....The only REAL change is the fact that the Video & Audio are
> now in a Digital Format...that Carrier is still the same as it was when they
> started tranmitting in the 50's or later.
> 
> Now as far as I know, most TV stations have One Antenna, which means they
> are Omnidirectional, if they had 2 or 3 antennas on different masts, then
> they can change the phase/polarity of different antennas and
> cancel/reinforce whatever they wanted and make it mult-lobed or highly
> directional.....
> 
> Damon B
> Telrad Electronics
> Fort Wayne IN
> ----- Original Message ----- 
> From: "AL LEATHERMAN" <alleathe@xxxxxxxxxxx>
> To: <techassist@xxxxxxxxxxxxx>
> Sent: Thursday, September 15, 2005 9:22 AM
> Subject: [TechAssist] Re: Fw: Are onidirectional antennas any good(roof)
> 
> 
> 
>>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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