VHF/UHF Remote coax switch recommendations

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

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  1. N5ATM

    N5ATM XML Subscriber QRZ Page

    Hi all,

    I'm currently putting up my first tower and will soon have the ability to dip my toe into the 2m weak signal pool, something I've always wanted to try. I have a 2m/440 vertical for FM and am doing some research/searching for a 2m beam. Since my shack is about 150' from the tower, I was thinking of trying to save some money on coax by switching between the antennas with a remote coax switch.

    1. Is a remote switch a good or bad idea at VHF?
    2. If the idea is sound, what would you be the recommended for the switch.

    I normally shun anything from MFJ (too many bad experiences) but thought I "might" try their remote switch if I could find a used one. Let me know your thoughts/recommendations. Thanks.
     
  2. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    For VHF (144 MHz and above), and even more so for UHF, the popular "ham radio" remote antenna switches won't cut it; although several work fine at HF and even at six meters.

    I'd look for a surplus Transco product, many of which are 28Vdc activated because they're military products. Almost all are weather-resistant or weatherproof. The ones with type N connectors can almost always handle a kW or more power, and most are good to at least 3 GHz with no measurable loss and very low VSWR.

    Examples: https://www.surplussales.com/Relays/rfcoaxialrelays/rfcoax_n.html

    There are a lot of these on the surplus market, but be careful as some:

    -Have a weird power (activation signal) connector and if the connector doesn't come with them, you may have a hard time finding one
    -Have BNC, TNC or SMA connectors which work fine at VHF-UHF-SHF but may imply the relay is for smaller signals and won't handle high power

    These are available in latching and non-latching versions, either of which can work fine but you may have to source or build a power supply to activate them.

    Still...they're really good at VHF and none of the MFJ-Ameritron-DXE-et al. stuff really is.
     
    AA7QQ and WA7PRC like this.
  3. WA7PRC

    WA7PRC Ham Member QRZ Page

  4. AA7QQ

    AA7QQ Ham Member QRZ Page

    As usual, right on the money, Steve.
    You just want a good quality RF relay/switch on the tower. There are many designs. I have a couple 4 way Transco ones with N connectors. 1 will be spare & 1 will be fed by7/8" heliax. On mine, the #1 connector is Normally Closed, meaning that the antenna most used (Discone) will be connected to it. 6M, 2M & 70cm yagis will be connected to the other ports.
    At a 75' run, cat5 wire (With pairs shorted) should do just fine for control. 24VDC supplies work just fine with these.
    EBAY or the For Sale forums are good places to look.

    Ed
     
  5. N3DT

    N3DT Ham Member QRZ Page

    I found a 6 position Sage RF switch that was great until I socked a KW into it with a bad antenna and ate the switch. It was a rotary latching switch and I got it for about $120. Had N connectors on it. They may still be around but you'll have to look. It was good through 500MHz or so. If it's just SPST and low power (less than 100W) you should be good with one of the Military BNC types. Lots of them run off 28V. They should be easy to find, I've got a few.
     
  6. KC6RCM

    KC6RCM Ham Member QRZ Page

    I've been using a remote antenna switch by hofi on; 50, 144, 222 and 432 MHz weak signal and it works well.
     

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  7. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    The HOFI stuff is good.

    Where did you get it, and what did it cost?

    Their designs are similar to the old Transco stuff, and should work well.
     
  8. KC6RCM

    KC6RCM Ham Member QRZ Page

    I purchased the HOFI series 2000 and other related pieces from Array Solutions, but don't recall the grand total. www.arraysolutions.com

    At the time, I also purchased additional HOFI items such as; PS 2621 control unit, HO 2011 outside mounting bracket and weather hood, HO 2005 five position manual switch and a HO 606 front plate (for other radio/amplifier switching in the shack).

    -Doug
     
  9. N3DT

    N3DT Ham Member QRZ Page

    That HOFI looks somewhat like the Sage I had. I'll bet it was expensive. Of course mine came with nothing, just the switch.
     
  10. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    The SAGEs and several others are all very similar to the Transcos (I think Transco was acquired by Dow-Key some time ago). Mostly sold to the military at high $$ and rated to 3 GHz or higher.

    The HOFI does look a lot like the same basic design, maybe not "mil spec" where they have to meet fungus requirements and all sorts of stuff hams don't really need, but electrically probably similar. Looks like a good choice, although surplus Transco, Sage et al. stuff can still be found for reasonable prices.

    Last Transco 6-port remote switch I bought was probably 20 years ago now and it cost $50 at the TRW Swap Meet. The seller guaranteed absolutely nothing about it, and I'm not sure he even knew what it was. Turns out it was evidently "brand new" (maybe 10-20 years old, but unused) and I suspect the first time I activated it was the first time since it left their factory.
     

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