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Like many hams I have several radios and several antennas. instead of constantly connecting and disconnecting coax cables I would like to feed several antennas in to some type of switch so I can select which antenna. Unused antennas should connect to ground.

Ideally a second switch could select which radio to connect to. For now assume I will only use 1 radio at a time.

There are commercial coax switches, but they seem to be expensive. Is there an inexpensive switch or relay I could use to home brew my own switching system?

I know UHF and even VHF can be challenging to switch so I will primarily be concerned with H, but one that would also work with VHF and possible UHF would be good as long as they are not too expensive.

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    $\begingroup$ What's your budget? How many rigs and antennas? How do you want to control the switch? Shack computer, USB/Ethernet/RS232, rPI, other? What additional features do you need: fail-safe, time-out, etc.? $\endgroup$ – Brian K1LI Mar 27 at 20:36
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    $\begingroup$ This question asks for recommendations for specific products, services, software, or electronic designs, which are off-topic as they attract opinionated rather than comprehensive answers. Please consider rephrasing your question in terms of what you should be looking for given your use case or whether a specific product has the capability you need. $\endgroup$ – Marcus Müller Mar 27 at 22:01
  • $\begingroup$ how much power are you planning to push through? This is almost trivial for a 15 dBm transceiver, up deep into the microwave frequencies, but hard if this has to withstand 100W on a 50Ω impedance. $\endgroup$ – Marcus Müller Mar 27 at 22:06
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    $\begingroup$ also, albeit commonly called "coax switches", what you need is an RF relay; the internal construction doesn't matter to you. Have you looked through the relevant products at one of the large electronics distributors? USD5 doesn't sound all too expensive for me, considering most of these will reliably work up to 2.6 GHz. $\endgroup$ – Marcus Müller Mar 27 at 22:09
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RF-specific parts aren't really required at HF. The physical dimensions of ordinary switches and relays are so small relative to the wavelengths involved that as long as you make a reasonable attempt to keep the leads short, it will work just fine.

Specific product recommendations are off topic, but there's really no need. Just be mindful of current and voltage ratings (which won't be difficult for powers up to 100W) and you're set.

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    $\begingroup$ Yes! For example the relays in a (100 W) antenna tuner are just small 250 V relays, nothing very special. $\endgroup$ – tomnexus Mar 28 at 6:40
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Here's one you could homebrew, using a diode matrix, push button switches magnetic latch relays and SO-239s. The schematic shown is for 3 antennas but it's extendable.

Freewheeling diodes for the relay coils and LED indicators are not shown.

The SO-239 bodies are to be mounted on the aluminium enclosure, interconnected and earthed.

Reliable operation would be ensured with the use of relays having gold-plated contacts.

enter image description here

enter image description here

Pushing a button selects an antenna and an indicator LED lights up. Unused antennas are grounded by the relay NC contacts.

An identical unit could be used to select the radio.

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