DIY coax antenna switchers

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wilburt
Posts: 5
Joined: Fri Dec 16, 2016 6:03 pm
Location: Leeds ,UK

DIY coax antenna switchers

Post by wilburt » Sat Dec 17, 2016 7:26 am

Hi,
what are your thoughts on homemade coax antenna switchers?
i asked in another post about just wiring two different antennas together but now found out it doesnt work.
can i just make one with a rotary switch in a metal box?
or maybe make a switcher with relays?

can i have some of your views/ideas
i would like to use a discone and circular polarised antenna and switch between the two.

Thanks!

joe36
Posts: 36
Joined: Wed Jul 20, 2016 11:09 pm
Location: Cass co. in. 46994

Re: DIY coax antenna switchers

Post by joe36 » Sun Dec 18, 2016 12:42 am

A rotary switch will work fine. There is a minimal amount of insertion los as with anything. Good workmanship, short leads and shielding will help keep loses down.
Joe KA9UCN

Kenn
Posts: 51
Joined: Fri Apr 08, 2016 8:43 pm

Re: DIY coax antenna switchers

Post by Kenn » Sun Dec 18, 2016 11:44 pm

I'll second what Joe said. Every antenna switch I've ever opened has a rotary switch. I see no reason you couldn't use a toggle or push-button switch (unless you plan to send a lot of power through it). A two-antenna switch can probably be had pretty cheap, but the nice thing about DYI is you can make it with whatever connectors you're using plus the satisfaction of making something custom. An all-metal enclosure would be best for shielding.

-K

Hardened Power
Posts: 3
Joined: Sat Jan 07, 2017 7:22 pm

Re: DIY coax antenna switchers

Post by Hardened Power » Sun Jan 08, 2017 3:30 pm

I wonder if a simple DTDP switch would do a decent job of switching between two antennas?

Edited to clarify: reception only, of course. ;-)

DB Gain
Posts: 13
Joined: Tue Dec 20, 2016 8:20 pm

Re: DIY coax antenna switchers

Post by DB Gain » Sun Jan 08, 2017 5:06 pm

As long as isolation and loss are inconsequential, a humble dpdt or other similar switch will do, but if you're using the system at microwave freqs the losses will be pretty steep.

AD5NL
Posts: 34
Joined: Fri Sep 16, 2016 7:00 pm

Re: DIY coax antenna switchers

Post by AD5NL » Mon Jan 09, 2017 7:09 pm

For receive only most switches should work.

Only concern I would have would be at high UHF and above, where the switch itself is going to start to look like a significant fraction of the wavelength.

Come to think of it, I might add a switch to my cross-polarized yagi project for 144 MHz, just to be able to switch between linear and circular polarization (by switching between a terminating resistor and the second yagi).

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