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(OT) : "Off-Topic" FM & TV Antenna Questions
OK here are a few "Off-Topic" FM & TV Antenna Questions
I have seen two general types of Multi-Element Yagi type TV Antennas 1 - The most common is the Multi-Element Yagi type TV Antenna with "Flat" Straight-Line Elements. ----------o---------- ----------o---------- ----------o---------- ----------x---------- ----------o---------- 2 - The less common is the Multi-Element Yagi type TV Antenna with slightly "Bent" Canted "Vee" - about 15 Degress Elements. The Tips of the Elements pointed slightly to the Front of the Antenna. See the Log Periodic Dipole Array (LPDA) Image http://www.hdtvprimer.com/ANTENNAS/G...yG.html#logyag Question : What does the "Canting" of the Antenna Elements Do ? ? Does it Broaden the Angle of Reception {Capture Area} of the Antenna over the "Flat" Straight-Line Elements ? ? -Or- Does it Narrow the Angle of Reception {Capture Area} of the Antenna over the "Flat" Straight-Line Elements ? ? What about Front to Back (F2B) vice Side Signal Reception ? * "Flat" Straight-Line Elements -vice "Canted" Elements ? Which has the better Front and less Side Reception ? ? Which has the good Front and fair Side Reception ? * * * New Set of Questions * * * The common Multi-Element Yagi type TV Antenna which has "Flat" Straight-Line Elements. ----------o---------- ----------o---------- ----------o---------- ----------x---------- ----------o---------- # 1 - When mounted Horizontal "Flat" is very Directional with a good Front-to-Back Signal and very good attenuation of the Side Signals. # 2 -if- It is mounted Vertical {With the Tips Up-and-Down} it is still some what Directional with a good Front-to-Back Signal and now has fair Side Signals making it closer to an Omni-Directional Antenna with some Attenuation of the Signals coming from the back-end. Question - Are Both # 1 and # 2 Correct ? - - - If Not - Why Not ? (OT) - Cause I know it is not Shortwave -but- at lease it is not : Religion, Politics or Sex. i want to know ~ RHF |
#2
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(OT) : "Off-Topic" FM & TV Antenna Questions
In article . com,
RHF wrote: OK here are a few "Off-Topic" FM & TV Antenna Questions I have seen two general types of Multi-Element Yagi type TV Antennas 1 - The most common is the Multi-Element Yagi type TV Antenna with "Flat" Straight-Line Elements. ----------o---------- ----------o---------- ----------o---------- ----------x---------- ----------o---------- 2 - The less common is the Multi-Element Yagi type TV Antenna with slightly "Bent" Canted "Vee" - about 15 Degress Elements. The Tips of the Elements pointed slightly to the Front of the Antenna. See the Log Periodic Dipole Array (LPDA) Image http://www.hdtvprimer.com/ANTENNAS/G...yG.html#logyag According to a quick skim of my copy of "The ARRL Antenna Book", they're not Yagi antennas. The key indication that it's a Log Periodic antenna is the feedline that runs the length of the active elements, zigzagging back and forth, both sides of a balanced line connecting one element to the next element down the boom on the opposite side. Ending up with a shorting stub at the back end. The feedline goes to the front end, the direction with the most gain. A lot of these multiband TV antennas are a combination Log Periodic and Yagi with some unconnected director and reflector elements bolted right to the boom. Question : What does the "Canting" of the Antenna Elements Do ? ? Does it Broaden the Angle of Reception {Capture Area} of the Antenna over the "Flat" Straight-Line Elements ? ? -Or- Does it Narrow the Angle of Reception {Capture Area} of the Antenna over the "Flat" Straight-Line Elements ? It converts a LPDA (Log Periodic Dipole Array) to a LPVA (Log Periodic V Array). This has a higher gain because the elements can then operate on harmonic frequencies, making more of the antenna work at the same time. A LDPA only uses a small section of the elements on any one frequency. ? What about Front to Back (F2B) vice Side Signal Reception ? * "Flat" Straight-Line Elements -vice "Canted" Elements ? Which has the better Front and less Side Reception ? ? Which has the good Front and fair Side Reception ? Beats me. Usually higher gain means better directivity. * * * New Set of Questions * * * The common Multi-Element Yagi type TV Antenna which has "Flat" Straight-Line Elements. ----------o---------- ----------o---------- ----------o---------- ----------x---------- ----------o---------- # 1 - When mounted Horizontal "Flat" is very Directional with a good Front-to-Back Signal and very good attenuation of the Side Signals. # 2 -if- It is mounted Vertical {With the Tips Up-and-Down} it is still some what Directional with a good Front-to-Back Signal and now has fair Side Signals making it closer to an Omni-Directional Antenna with some Attenuation of the Signals coming from the back-end. Question - Are Both # 1 and # 2 Correct ? - - - If Not - Why Not ? This isn't clear here. Are the elements horizontal or vertical? Is the boom horizontal or vertical? If vertical, pointed up or down? Are the signals you want to receive horizontally (broadcast) or vertically (police/fire/mobile) polarized. Mark Zenier Googleproofaddress(account:mzenier provider:eskimo domain:com) |
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(OT) : "Off-Topic" FM & TV Antenna Questions
RHF wrote:
(OT) - Cause I know it is not Shortwave -but- at lease it is not : Religion, Politics or Sex. i want to know ~ RHF . . . . Yes it is OT, so why do you post it? Can't you figure out how to use Google? If you are so concerned about OT posts in this group, STOP POSTING THEM YOURSELF! |
#4
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A Few FM and TV Antenna Questions {Clarifications}
- - - Sorry this is a Revised Re-Post - - -
Thank you for your replies and now I I understand the difference between the Yagi Antenna and LPDA Antenna. But that is not the focus of my questions : A Few FM and TV Antenna Questions {Clarifications} I have seen two general types of Multi-Element FM & TV Antennas : 1 - The most common is the Multi-Element FM & TV Antenna with "Flat" Straight-Line Elements. http://tinyurl.com/3xbbfz http://www.solidsignal.com/prod_display.asp? PROD=ANC3679&xzoom=Large#xview Top View : .....Front v ----------o---------- ----------o---------- ----------o---------- ----------x---------- ----------o---------- ......Back ^ 2 - The less common is the Multi-Element FM & TV Antenna with slightly "Bent" Canted "Vee" - about 15 Degress Elements. The Tips of the Elements pointed slightly to the Front of the Antenna. See the Log Periodic Dipole Array (LPDA) Image http://www.hdtvprimer.com/ANTENNAS/G...yG.html#logyag http://tinyurl.com/2w7ssp http://www.solidsignal.com/prod_display.asp? PROD=ANCM3019&xzoom=Large#xview OK - I understand the difference between the Yagi and LPDA Antennas. MY QUESTION IS : What does the "Canting" {Slight 'Vee' Shape Bent} of the Antenna Elements Do ? ? Does it Broaden the Angle of Reception {Capture Area} of the Antenna over the "Flat" Straight-Line Elements ? ? -Or- Does it Narrow the Angle of Reception {Capture Area} of the Antenna over the "Flat" Straight-Line Elements ? ? What about Front to Back (F2B) vice Side Signal Reception ? * "Flat" Straight-Line Elements -vice "Canted" Elements ? Which has the better Front and less Side Reception ? ? Which has the good Front and fair Side Reception ? * * * New Set of Questions * * * The common Multi-Element FM & TV Antenna which has "Flat" Straight-Line Elements. # 1 - When mounted Horizontal "Flat" is very Directional with a good Front-to-Back Signal and very good attenuation of the Side Signals. Top View : .....Front v ----------o---------- ----------o---------- ----------o---------- ----------x---------- ----------o---------- ......Back ^ # 2 -IF- It is mounted Vertical {With the Tips Up-and-Down} it is still some what Directional with a good Front-to-Back Signal and now has fair Side Signals making it closer to an Omni-Directional Antenna still with some Attenuation of the Signals coming from the back-end. * A "Cardioid" {Heart-Shaped} Antenna Reception Pattern Top View : ----------- Side Front o o o x o Back ----------- Side MY QUESTION IS : Are Both # 1 and # 2 Correct ? - - - If Not - Why Not ? NOTE - OK not about Shortwave -but- It is about Antennas. i want to know -cause- iane ~ RHF |
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