Homebrew Antenna Switch

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Trog
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Homebrew Antenna Switch

Post by Trog »

Has anyone here ever built an antenna switch? Is it as straightforward as my drawing shows providing a metal enclosure is used for screening, a switch with a high enough current rating is used and the connections are made using copper wire that is thick enough or is there more to it than that?
Antenna Switch.jpg
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Admiral
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Re: Homebrew Antenna Switch

Post by Admiral »

You could get away with it on HF maybe, but would be very lossy on V/UHF.

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Trog
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Re: Homebrew Antenna Switch

Post by Trog »

It would only be for HF but I'm wondering what a commercially made switch would have that this one (if built) wouldn't have.
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Re: Homebrew Antenna Switch

Post by Mattylad »

A pretty label, A manufacturers warranty and a higher cost.

If you look inside some then they are simply just what you have described.
You have to consider the voltage you are putting through them, getting a good quality switch and sockets - bond them well and ensure you make good soldered joints and it should be fine.

Having seen inside a few - I'd make one myself for HF if I needed one rather than spend whats being asked for them.
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Re: Homebrew Antenna Switch

Post by Samalex »

"Trog » 30 Apr 2015, 23:49
It would only be for HF but I'm wondering what a commercially made switch would have that this one (if built) wouldn't have"

better isolation from port A to B
Possibly lower insertion loss
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Re: Homebrew Antenna Switch

Post by Mattylad »

What makes it better when the manufacturer just uses the case and a switch with wires?

So it's not necessarily "better".

IMO there is no harm in trying - make your own and see how well it performs.
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Trog
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Re: Homebrew Antenna Switch

Post by Trog »

Looking at pictures of the inside of a commercial antenna switch, I can see where the ports are screened from each other by the metal of the case extending between them. http://www.alphadeltacom.com/pg3.html
I'm wondering if this is more for users that intend to connect two (or more) rigs to one antenna rather than one rig to two (or more) antennas. I could probably 'rig' up ('scuse the pun) some sort of screening between the two adjacent ports if I had to or, perhaps, use coax inside the box instead of single wires.
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Re: Homebrew Antenna Switch

Post by cjay »

Have a look at the internals of a *proper* coaxial relay, the sizes of the leaf, the chamber it's mounted in etc are all carefully machines to match characteristic impedances. Then look at most of the HF antenna switches out there and see how much they get away with :)
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Re: Homebrew Antenna Switch

Post by Maple »

This is one of the best introduction-DIY projects to RF. The most important thing is that you use a proper RF capable switch. Good luck :thumbup:
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Re: Homebrew Antenna Switch

Post by LastTemplar »

I have a 2 antenna switch here. Produced in the 80s and it is just 3 sockets hard wired via a rotating switch.

To say its very basic is an understatement im sure it cost my dad a few quid back in the day. Cant imagine why he had it we only had one twig on the house.... a big mother!
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Re: Homebrew Antenna Switch

Post by Gw0wvl »

Heres my home made two way switcher.. using a 16 amp rocker switch, Its wired up so the unused S0-239 is grounded..Done some tests with it and its usable upto 6 mtrs without to much loss, At the top end of HF losses are low and on the Lower HF bands i cant measure the losses there that low..

I made this some 5 years ago now and its still running without fault.. On HF Ive put the full Legal 400 watts for The Ham bands through it without any problems ..

http://s925.photobucket.com/user/madmar ... rt=3&o=533

http://s925.photobucket.com/user/madmar ... rt=3&o=534

http://s925.photobucket.com/user/madmar ... rt=3&o=535

http://s925.photobucket.com/user/madmar ... rt=3&o=537
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Re: Homebrew Antenna Switch

Post by Mattylad »

Nice.
Grounds the unused antenna - many do not do that.
Also nice tower & beam on top, nice transformer - that's gonna make a cracking PSU. :)
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Re: Homebrew Antenna Switch

Post by Trog »

Thanks for sharing those pictures GW0WVL.
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Re: Homebrew Antenna Switch

Post by emilytran »

Thank you so much and learned!!!!
Hey Nice to meet you everyone. I just here to learn. I heard about http://transmission1.net few days ago from a blog.
My name is Emily and newly married, i am also a blogger and love to share my experiences on it. my Blog
thanks
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