June 2013
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The Shively Branched combiner

Did some work a while ago at a transmitter site that had three transmitter combined into one antenna.  The site uses a Shively branched combiner:

Shively Branched combiner

Shively Branched combiner

Each transmitter can be tested into a separate 20 KW dummy load:

Three inch coax switches

Three inch coax switches

Transmitter themselves are Nautel NV15s:

Nautel NV20 transmiters

Nautel NV15 transmiters

Except the one on the end, which is an older BE FM20A.

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7 comments to The Shively Branched combiner

  • Bob M.

    Except the photo shows NV15 transmitters, not NV20.

  • Paul Thurst

    Doh! I changed to caption on the photo but forgot to change the sentence above it. Thanks, Bob.

  • This in Florida? I’m trying to think of a three station combined antenna array around here, other than one in Eastern Vermont.

  • Paul Thurst

    Nope, not Florida. Can’t really say where this is exactly for various reasons.

  • Wow…a BE with the keyboard still attached! Does the video system still work?

    Did you do any tuning or work on the combiner? Curious to hear your thoughts on Shively combining systems. I’ve always used Dielectric, but with them gone, I’m doing a complex Shively combiner project over the summer.

  • Scott Cason

    That’s nice! I have three stations combined using an ERI combiner in Louisville. There’s a nice 20kW dummy sitting in the corner, but since nobody made switching provisions, that’s all it does is sit. 🙁

  • Paul Thurst

    @ Chris, I don’t know if that video systems works, I have never tried to turn it on. Since all the parts are still there, I would guess yes. We have a BE FM30A in Bridgeport that still has a working video system.

    As far as the combiner goes, we have not had to do anything with this one. There is one in Florida that needed to be touched up a little after it was installed. That involved using a network analyzer, I wouldn’t attempting it with anything less than a spectrum analyzer with a tracking generator and appropriate directional coupler.

    I generally like the Shively products.

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