Author Topic: Antenna design  (Read 3009 times)

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Offline martins

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Re: Antenna design
« Reply #15 on: May 11, 2014, 01:38:37 AM »
no offence taken, had a giggle that's all

Offline northdublin

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Re: Antenna design
« Reply #16 on: March 08, 2015, 00:43:03 AM »
been busy the last while re-building a quad antenna.
its a copy of a maco antenna and when i originally built it, it seemed to work very well.
since then i've had to take it down as ive moved house and i can no longer put up such an antenna.
so the plan is to make it better and give it to a friend who is going to put it up and run it for a while.
ive tried to make it as cheaply as posible but still keep the weight down and make it durable.
i have made the hubs from galvinised 4 way junction boxes with the back drilled out so they slide onto my boom and are locked in place with m8 grub screws.
the brass ferrules at the end of the hubs are drilled out to the exact diameter of the aluminum tubing used for the elements.
the elements are held in the hubs with m4 grub screws.
the gamma tubes are connected to the 3/8 thread on the so239 connector using stainless dublee clips and the gamma straps are made from aluminum bar. the end of the gamma rod is covered in heat shrink and slides into the gamma tube.
i plan to put it up over the next week or so and will report back.
the last pic is when it was up originally












kenwood ts 870
Yaesu ft-857
sirio gainmaster
inverted vee
chameleon ch v1

Offline scannyman

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Re: Antenna design
« Reply #17 on: March 09, 2015, 23:16:09 PM »
Well done, fabrication looks excellent!

Offline 5566

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Re: Antenna design
« Reply #18 on: March 10, 2015, 02:30:24 AM »
Great stuff! Again I am impressed with your solutions.

Offline northdublin

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Re: Antenna design
« Reply #19 on: March 10, 2015, 10:39:37 AM »
thanks, i wish i could make the hubs from aluminum but i'd need a decent lathe and tooling to do it.
the junction boxes are galvanized so have some protection from the elements.
the boom diameter is quite large but its the best size for the internal diameter of the galv box used for the hub.
the elements sit nice and straight in the short supports made from 20mm couplers and the brass end is takin from an swa gland pack and drilled out to exact size of the aluminum tubing.
the junction boxes, the couplers and the brass ends all have a standard 20 mm thread commonly used in the electrical trade so go together in a matter of seconds.
the bar i used for the gamma straps is more commonly used as a heat sink behind led strip lighting.
short sections of fibreglass isolate the wire from the spreaders and each fibreglass end has a copper lug crimped onto the end for the wire to bolt to.
« Last Edit: March 10, 2015, 10:43:49 AM by northdublin »
kenwood ts 870
Yaesu ft-857
sirio gainmaster
inverted vee
chameleon ch v1

Offline 5566

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Re: Antenna design
« Reply #20 on: March 12, 2015, 05:02:50 AM »
What I like most about your antenna is a tidy job done using very basic components.