transceiver amplifier tuner wattmeter antenna

Discussion in 'Amateur Radio Amplifiers' started by KC9JYW, Jan 5, 2019.

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  1. KC9JYW

    KC9JYW Ham Member QRZ Page

    Is the above the CORRECT order for connection?
    Transceiver to in of amp, out to in of tuner, out to in of wattmeter then out of meter to antenna?

    I have seen various ways but would like to know the correct best way for connection please. Thanks all for any help
     
  2. N7WR

    N7WR Subscriber QRZ Page

    yep that works
     
  3. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    I'd say that doesn't work...well.

    The reason is, in that configuration the wattmeter won't accurately indicate power unless your antenna happens to look like 50 Ohms, in which case you wouldn't need the tuner.

    It's better to put the wattmeter between the amplifier and the tuner, and connect the tuner directly to the antenna feedline. That way, you can adjust the tuner for minimum SWR as indicated by the wattmeter, and once the tuner provides a match, the meter will indicate accurately.
     
    K7MH and K7TRF like this.
  4. KM3F

    KM3F Ham Member QRZ Page

    Have to respectfully disagree with putting the watt meter between the amplifier and the antenna.
    If the antenna is not an SWR below 1.5 to one, the watt meter will not be accurate for indication as you move frequency.
    Because the watt meter is designed on the basis of a 50 ohm impedance.
    If the impedance seen by the watt meter is quite different, it adds the forward power to the reverse to cause the meter to respond either higher or lower.
    You really need to put the watt meter between the amplifier the tuner to see the best match the tuner provides to the watt meter.
    .
    Note, placing the watt meter between the radio. and amplifier indicates when you have a match and allows the watt meter to read more accurate at the 50 ohm design impedance.
    A support to the last replay with a little more info on why.
     
    K7TRF likes this.
  5. K7TRF

    K7TRF Premium Subscriber QRZ Page

    Nope, as posted above the correct order would be:

    Transceiver > Amp > Watt Meter > Tuner > Antenna

    So that the watt meter sees a load close to 50 ohms and reads accurately. The key thing is that most amateur watt meters are really volt meters or current meters and accurate readings are based on the assumption that the meter is working into a 50 ohm load.
     
    N6UH likes this.
  6. KM3F

    KM3F Ham Member QRZ Page

    I should add that putting the meter between the radio and amplifier would allow adjusting. the tuner for best match......through.... the amplifier at the radio drive level.
    When the amplifier is keyed up, the meter only see the amplifier input match and radio drive power not the amplifier output power level.
     
  7. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    No benefit to doing that, as the meter won't indicate anything about "tuning up" the amplifier, and putting the meter after the amp but before the tuner will allow adjusting the tuner for a best match either way, barefoot or with the amplifier engaged.

    It really doesn't matter if you know the power level between the radio and the amplifier; what's important is what you have after the tuner is adjusted, so you want to see that after the amplifier.
     
  8. N8CMQ

    N8CMQ XML Subscriber QRZ Page

    My tuner has a watt meter as does my amp, so I have it covered both ways.
     
  9. KE0ZU

    KE0ZU Ham Member QRZ Page

    As Jeff mentions, most tuners have a built in Watt meter, many with dual needle types.

    A 50 Ohm load would be a nice thing to have as well. Tune the radio into the dummy load first, then, connect the radio to the antenna tuner, and, adjust the Tuna to match the antenna.
     

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