remote antenna relays

[mylond]

I'm trying to build a remote antenna switch. what's the best relay (manufacturer) for better rf shielding. any help or schematic is wellcomed.
thanks

 

[Nigel Goodwin]

I'm trying to build a remote antenna switch. what's the best relay (manufacturer) for better rf shielding. any help or schematic is wellcomed.
thanks

You can buy special RF relays for this very purpose, a lot depends on the frequencies and powers involved, but they usually have some kind of coaxial connectors on them and are fully screened.

 

[stevez]

I've seen what appear to be standard relays used for RF in quite a few things. As Nigel points out, it all depends on the frequency. Still, I see common relays in use in RF circuits of VHF equipment. It looks like LDG and other automatic antenna tuner mfrs use common relays. My guess is that they don't perform as well but in some applications the losses are acceptable. Coaxial RF relays are very expensive too. I've wanted to build up some remote antenna switching units and thought about trying to measure the losses, mismatch, etc of low cost, common relays at 30 mHz and below. Would be nice if someone has already done that.

 

[Nigel Goodwin]

I've seen what appear to be standard relays used for RF in quite a few things. As Nigel points out, it all depends on the frequency. Still, I see common relays in use in RF circuits of VHF equipment. It looks like LDG and other automatic antenna tuner mfrs use common relays. My guess is that they don't perform as well but in some applications the losses are acceptable. Coaxial RF relays are very expensive too. I've wanted to build up some remote antenna switching units and thought about trying to measure the losses, mismatch, etc of low cost, common relays at 30 mHz and below. Would be nice if someone has already done that.

Another possibility is PIN diodes instead of relays, a lot depends on what it's actually for, he doesn't mention if it's for transmitting or just receiving, and if transmitting, what sort of powers are involved.

 

[stevez]

Just got thru adding up the parts cost for a 2 meter (146 mHz) amplifier. It uses 2 relays (dpdt) that are $9.95 each from RF Parts so that's no too expensive. I'd have to deduce that the losses at 146 mHz are fairly low because it's output of 50 watt module. Part no. is 221D012 for your information. I think the way it is mounted to the board contributes to the low loss.