Question about coaxial relay - Page 1
Forum section: electronics / rf-microwave

author: mio83
author_rank: Regular Contributor
timestamp: June 25, 2020, 08:27:56 pm
content: Hello,super noob question.recently, buying a ham radio "lot", I entered in possession of a "TRANSCO 14100 SP4T Switch-RF XMSN line (28 volts)".I couldn't find many informations online, it's only listed here:http://www.surplussales.com/relays/rfcoaxialrelays/rfcoax_n.htmlsee picture:http://www.surplussales.com/Images/Relays/CoaxialRF/kc-14100_thumb.pngIn that site it says "DC-12.4 GHz / 28v DC", so (if it's true, I couldn't find the datasheet) it's notbasicham-radio stuff but rather lab-level RF equipment.Does anyone have any informations (datasheet) about it? I couldn't find any.What could be a purpose of a switch like this in a Lab environment? (sorry if this question sounds shocking, I'd like to know for what kind of testing, or measurements, this can be useful for). More generally, I have no idea how to use it (I imagining applying 28volts somewhere it will switch between the 4 ports?). Why it has this weird shape?As you can see, I have no idea of what to think about it. Perhaps I should re-sell it.[I am searching for reasons to not sell it, and accumulate "my precious"]Any idea about its possible (realistic) value?thanks a lot!

author: bob91343
author_rank: Super Contributor
timestamp: June 25, 2020, 09:32:42 pm
content: It's just a switch. My guess is that it latches, and after removal of coil power stays on whichever position it is in.You can use it for nearly anything low power to switch. Sure it goes to UHF. It would be used to compare up to four signals or loads by a simple switch throw.One could use it to select antannas, for instance.

author: radiolistener
author_rank: Super Contributor
timestamp: June 25, 2020, 10:45:21 pm
content: Quote from: mio83 on June 25, 2020, 08:27:56 pmMost of ham using it to switch antennas. It needs to be done remotely, so you can't just remove one connector and connect another, so such relay is used to switch desired antenna to single coax line. It allows to use single coax line for different antennas

author: mio83
author_rank: Regular Contributor
timestamp: June 26, 2020, 06:22:15 am
content: Thanks.So I guess these type of switches could be used by hams not just for HF, but also for VHF, UHF and above (Wifi, satellite up to 12Ghz, etc).If anybody reads this post and know of a datasheet and/or more informations (e.g., maximal wattage, which from what I have read on eBay descriptions should in the order order of >1kW) please post a link here.thanks again

author: bob91343
author_rank: Super Contributor
timestamp: June 26, 2020, 11:11:25 pm
content: Chances are it won't withstand 1 kW but I don't know. Very few items good to such high frequencies can handle high voltages and/or currents.

author: mio83
author_rank: Regular Contributor
timestamp: June 28, 2020, 10:14:45 am
content: Thanks a lot eb4fbz!

author: Andrey_irk
author_rank: Regular Contributor
timestamp: July 06, 2020, 06:04:40 am
content: Weird design.I think it is not intended for lab use. More like military aviation kind of stuff. But why notI've seen a Dow Key coax switch on ebay that was built for some british space satellite. There was no information about the switch whatsoever apart from this fact. The S-parameters were gorgeous. Like 1.15 VSWR up to 20GHz and less than 0.15dB of loss.