Celwave Duplexer Help

Discussion in 'General Technical Questions and Answers' started by W8HDU, May 18, 2009.

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  1. W8HDU

    W8HDU XML Subscriber QRZ Page

    Has anyone on the 'Zed worked with Celwave mobile style duplexers?

    I have one that appears to be a 6-cavity unit. (see below) The tag on it says;

    Cat No: 01-83496R03
    Serial #: 02-21E-87

    From postings on Repeater Builder, it appears to be a Model 633-6A.

    Does anyone know where I can pick up some specs on this unit, perhaps a PDF of tuning instructions?

    From what I can tell from the construction, it seems to be a notch style duplexer. I'm wondering what the limits are on the device. I would like to see if it would do 449.9 on one port and 433.5 on the other.
  2. K9STH

    K9STH Ham Member QRZ Page

    You may have problems going all the way down to 433 MHz using this duplexer. I have used the same basic design on a commercial 25 watt output repeater in the 462 / 467 MHz range and it worked fine with the 5 MHz split. However, it didn't like going much below around 442 MHz.

    Glen, K9STH
  3. K7JEM

    K7JEM Ham Member QRZ Page

    It might work. Two things are out of spec, though. They typically recommend those for 10MHz max separation, but it may work that far, I've never tried one. The other thing is the 433 frequency may not tune, but then again it might.

    You really just need to try it. One side is low notch, high pass. The other side is high notch, low pass. They need to stay the same, regardless of finished freq. Should have 75+ dB of notch and less than 1.5 dB of insertion loss.

  4. AF6LJ

    AF6LJ Premium Subscriber QRZ Page

    I have tuned a few dozen of those and have repaired a few.
    It's not likely to make it down as far as you want without modification. The ones I tuned will do 5MHZ splits just fine.
    (they were intended for that used in mobile and low power fixed repeaters.)

    The Q on those is nothing to write home about, however they do the job.
  5. K8JD

    K8JD Ham Member QRZ Page

    If you try to do other than the 5 Mhz split (also observe the high and low labels) the insertion loss on the opposite freq will suffer badly. You really need a tracking generator so you can see what the bandpass looks like as you tune those notch adjustments.
    At my shop they call me Mr. Duplexer since I have tuned so many.
  6. W8HDU

    W8HDU XML Subscriber QRZ Page

    I've got all the test equipment necessary. I guess I'll take it out of the box and see what it can do.

    Most of the duplexers I have in my shop are the big blue DB Products and the newer 4" TXRX units.

    If it doesn't tune more than 5 or 10, I can always trade it for something that will work.

    Does anyone know where to find a manual on these?
  7. AF6LJ

    AF6LJ Premium Subscriber QRZ Page

    Good luck;
    Let us know how it turns out.

    While I have tuned quite a few of these little guys, I have never laid my hands on a manual. You would tune it just like any other band reject douplexer.
  8. W5RB

    W5RB Guest

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