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Multiple antennas selector switch...

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Externet

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What considerations to watch in order to build a four position (for selecting one of four antennas) coaxial switch ?
Layout, size, shielding, common shield ground...
It will have 75Ω, F connectors in all ports and should be good for UHF, reasonable low insertion loss, in a metal? (altoids?/tuna can?) box. What kind of selector switch is convenient ?
-Receiving only.
 
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MikeMl

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Surplus Ceramic rotary switch in a shielded box. Do you need to short/terminate the non-selected inputs?
 

Externet

Well-Known Member
Thanks, Mike.
Leaving unselected antennas shorted or open seems irrelevant.
But perhaps open-before-make contacts would be convenient as antennas are DC powered via the coaxial. (LNBs)
OK, ceramic; small as possible?, short wiring.
 

MikeMl

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...Leaving unselected antennas shorted or open seems irrelevant.
Lightning protection? For ham use, I want the best antenna-to-antenna isolation, so shorting the unselected antennas does both...
But perhaps open-before-make contacts would be convenient as antennas are DC powered via the coaxial. (LNBs)
OK, ceramic; small as possible?, short wiring.
The wires in the box from the F connector centers should be as short as possible. Get the switch first, and then locate the F connectors on the rear panel so that the wires (if any) are less than 1cm long...
 

bountyhunter

Well-Known Member
What considerations to watch in order to build a four position (for selecting one of four antennas) coaxial switch ?
Layout, size, shielding, common shield ground...
It will have 75Ω, F connectors in all ports and should be good for UHF, reasonable low insertion loss, in a metal? (altoids?/tuna can?) box. What kind of selector switch is convenient ?
-Receiving only.
Here is a single four position 50 Ohm switch:

http://www.birdrf.com/Products/Comp...ion-Coaxial-Selector-Switch.aspx#.V0dvO_nw9qA

You can also do it using the typical cheap "A-B" two position switches if you use three of them and interconnect with cable.

https://images.search.yahoo.com/images/view;_ylt=AwrTcXK_b0dXaQwABhounIlQ;_ylu=X3oDMTIycDAxMXNvBHNlYwNzcgRzbGsDaW1nBG9pZANlMmEyZGVjYTQ3NDYwYWE0MWY0MzAyMGRkNmNjZDVlYgRncG9zAzEEaXQDYmluZw--?.origin=&back=https://images.search.yahoo.com/yhs/search?p=75+Ohm+Antenna+Selector+Switch&fr=yhs-mozilla-001&hsimp=yhs-001&hspart=mozilla&tab=organic&ri=1&w=550&h=550&imgurl=www.summitsource.com/images/products/SWAB15.jpg&rurl=http://www.summitsource.com/eagle-aspen-abswitch-slide-switch-video-selector-coaxial-cable-antenna-signal-dual-source-with-connector-loss-isolation-part-switch-p-8558.html&size=104.3KB&name=<b>Switch</b>+Video+2+Way+<b>Selector</b>+<b>75</b>+<b>Ohm</b>+Coaxial+Cable+UHF+/+VHF+TV+<b>Antenna</b>+...&p=75+Ohm+Antenna+Selector+Switch&oid=e2a2deca47460aa41f43020dd6ccd5eb&fr2=&fr=yhs-mozilla-001&tt=<b>Switch</b>+Video+2+Way+<b>Selector</b>+<b>75</b>+<b>Ohm</b>+Coaxial+Cable+UHF+/+VHF+TV+<b>Antenna</b>+...&b=0&ni=180&no=1&ts=&tab=organic&sigr=15b97afi7&sigb=14cf1h0uj&sigi=11f08ag5c&sigt=13c9qv9dd&sign=13c9qv9dd&.crumb=0NxTQO5604N&fr=yhs-mozilla-001&hsimp=yhs-001&hspart=mozilla
 

Externet

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Your link is for 50Ω and not needed Tx ; and multiple 'F' boxes may impose too much losses.

The switch was built and has been working fine for 3 days now; waaaay under $400. Like $4. Thanks.
 
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