Text 15473, 59 rader
Skriven 2019-06-13 15:16:00 av mark lewis (1:3634/12.73)
Ärende: building an antenna
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this is somewhat on the topic of HAM but the actual use is not... i don't know
where to look for the information i'm seeking...

here's the scenario:

i need to make an external UHF HD antenna...
i do not have any funds available...
i found plans for a UHF antenna online and printed them out...
they are using some copper tubing that is wrapped half around a 26inch bicycle
rim for shaping...
the bicycle rim is only for shaping... it is not used for the actual antenna...
there are two halves each making one half of a circle...
the two halves are mounted on PVC members to hold them...
the circle is horizontal to the ground...

so in simple terms, this is a dipole antenna that is circular so as to be
uni-directional...

what i want to do is to make four halves and mount the second two 90 degrees
out to avoid any (slight?) blind spots as well as to provide more area to pick
up the signals... what i'm not sure of is how far apart the two antenna circles
should be mounted from each other or how long the inter-connecting wires
between the two circles must/can be...

i'm taking the idea roughly from a turnstyle dipole antenna that has 16 bowtie
halves where the bowties are a specific distance apart... and cross wired from
bowtie half to bowtie half... i don't know the proper terms for these cross
wires connecting the bowtie halves, though...

i was (slowly) in the process of making the bowties (from some 10/2 electrical
wire) when someone (don't ask, bad shituation) took all my copper and now i
don't have any to build even that antenna any more... i also wanted to make a
simpler antenna... i absolutely want one that is unidirectional because i do
not want to have to go and be turning the dang thing just to watch different TV
channels... our existing rotor is dead and i'm certainly not in the position to
purchase another one... so a friend has offered to provide enough copper
tubing/pipe to make the antenna and if it works well, they want one, too...

so, two stacked circular dipole antennas with one circle turned 90 degrees
around the pole axis from the other circle... how far apart do the two circles
need to be? how long can the cross-connect wires be to link the two circles to
the balun/adapter where the 50ohm RG58 connects?

here's a link to an antenna that is very similar to what i'm looking to make...
i'm just looking at doubling the number of circles and connecting them together
properly...

  https://www.instructables.com/id/Homemade-TV-antenna/

advTHANKSance!

)\/(ark

Always Mount a Scratch Monkey
Do you manage your own servers? If you are not running an IDS/IPS yer doin' it
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... Lots of beef and oceans of grog. (Navy)
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 * Origin:  (1:3634/12.73)