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Thread: Fiplex - ever heard of them?

  1. #1
    syntrx No Longer Registered

    Default Fiplex - ever heard of them?

    I've been searching for a VHF duplexer for a planned MOTOTRBO system. The frequencies I'll have are on a 1.6MHz split.

    While hunting around, I came across these guys:

    http://www.fiplex.com/

    and specifically, their DHV 1633 helical resonator BP/BR duplexer:

    http://www.fiplex.com/sitionuevo/ofi...0duplexers.pdf

    DHV1633.jpg

    I've never heard of them, and their claimed minimum split of 1.5MHz, with 90dB of isolation and 1.5dB insertion loss on VHF high band that in something that's only 2x7x12 inches sounds a bit too good to be true.

    Anyone have any experience with equipment from this company, or for that matter have a recommendation for something reasonably compact for this split at a quiet site?
    Last edited by syntrx; Feb 22, 2013 at 10:12 AM.


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    A friend & I have used several Fiplex flatpacks on UHF for 420 duplex links. I've been impressed by their performance. They make a quality product from what I've experienced. Wouldn't hesitate to give them a shot! The DCL series are what we've used. I would imagine their DHV series is comparable.

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    I just got approval from my clubs general membership to purchase a low band set for our 6m repeater. Seems like good kit.

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    With all these electrically shortened duplexer types you can't run too much power before the receiver noises up, not from lack of isolation (although that can be an issue) but from corona noise caused by the very high voltages present at the ends of the tx resonant elements. These have a very small surface area compared to full sized cavities. Typically 25W is about the max in my experience at UHF, with what we call 'mobile duplexers'. YMMV. Be reasonable and they're good. Put too much juice in and the Teflon bits invariably used inside fry.
    Last edited by Astro Spectra; Feb 22, 2013 at 09:26 PM.
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    Quite right AS, lower power is important. Most are rated to 50W but I never run anything near that. In typical point-to-point 420 link service, if the path can't be made & sustained with 10-15W TPO (to the antenna, a 6-el yagi), it's not viable. Sustainable being worst-case 20dB quieting when taking a fade & all other conditions (RX sensitivity, TX power, frequencies zero'd, etc.) being nominal.

    Bottom line they're a compromise.

  6. #6
    syntrx No Longer Registered

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    Cool, thanks guys.

    This particular unit is rated at 150W (which is probably the point at which smoke comes out) but I don't plan to run more than 40W, and could probably get away with less anwyay. There are a couple of other designs that might suit this purpose that I'm checking out at the moment, the only real requirement with regards to size is that the cans and an XPR8400 can fit into a 6-8U Gator case.