VHF/UHF Remote coax switch recommendations

Discussion in 'VHF/UHF - 50Mhz and Beyond' started by N5ATM, Oct 24, 2019.

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  1. N3DT

    N3DT Ham Member QRZ Page

    The Sage I had looked like new. And it worked like that until I messed up. I replaced it with a SJ2W kit I got a couple years ago. Now I always make sure the right antenna is switched in with low power before I sock it with a KW. Lesson learned. I opened it up and there was a rotary contact that was burned up. HV from high SWR will do that. The latching relay was something else to behold. It took 28V to energize it and then it stopped drawing current until another position was selected. I think it always went around in one direction, but not sure.
     
  2. N5ATM

    N5ATM XML Subscriber QRZ Page

    Thanks for all the good info guys. I started looking around at the Transco but they have so many different ones I was confused but I'll figure it out eventually or maybe find someone with one who can give me the model number. Thanks again.
     
  3. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    There isn't any one model number.

    Anything you find will be surplus, so you take what's available.

    The key elements are:

    • How many switch positions do you need?
    • I'd recommend only those with type N connectors, as the ones with BNC/SMA/TNC/whatever may not handle serious transmitting power -- they're "smaller"
    • If you buy a surplus Transco, make sure it comes with the power connector; otherwise, the connector may be difficult to find and you'll end up being frustrated

    That's really about it. There are hundreds of model numbers, but it doesn't pay to zero in on one of them, as ten others could be just as good.

    The Transco "Y" coaxial switches are great, handle tremendous power, very low VSWR into the microwave region, and have two activating coils, so at least three wires (carrying DC) are needed to use one. They're basically "one common" port to "two different selectable ports," and if both coils are not activated it's an open circuit ("schedule 2" configuration). Activate one coil and one antenna is connected. De-activate that one, and activate the other one, and the other antenna is connected. If you activate both coils at the same time, both antennas are connected in parallel to the common! Very versatile, and very low-cost for very high-performance.

    Most of these units don't use a DC power connector, just stainless steel screw terminals, so interfacing them to your power/control source is very easy.

    Spec sheet on some popular "Y" models: https://www.surplussales.com/Relays/rfcoaxialrelays/pdf/kc-11200.pdf

    They have some of these listed here: https://www.surplussales.com/Relays/rfcoaxialrelays/rfcoax_n.html
     
  4. AA7QQ

    AA7QQ Ham Member QRZ Page

    This is the style I have. It's a Double Y, meaning SP4T. Pos.1 in NC & is disengaged when you engage pos. 2,3 or 4.
    It's also great for switching in phasing lines.

    Ed
     
  5. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    I've used those, also. Same concept but double the fun.

    The great thing about the "Y" switches is they're so versatile; another great thing is so many millions of them were made for various defense contracts there are thousands on the surplus market, many of which are "NOS" and were actually never used, selling at probably 10-20% of their original "government" cost. And because each coil has only two DC connections, a lot of them don't need any special connector to use them -- just wires.

    They're a real bargain.
     
  6. AA7QQ

    AA7QQ Ham Member QRZ Page

    Yup. Mine still had the red caps & there were no witnedd marks on the flathead screws.

    Ed
     
  7. AA2UK

    AA2UK Ham Member QRZ Page

    SSB Electronics has a nice 4 position switch that will handle up to 500 watts on 432MHz. If you have one on the tower and a 2nd (other) in the shack it's a decent VHF/UHF 4 position antenna & rig switch.
    Bill AA2UK
     

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