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How to hook up tuner and meter

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by KB1ORM, Jun 6, 2010.

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  1. KB1ORM

    KB1ORM Ham Member QRZ Page

    I just purchased an Alinco DX-70 HF/6M rig at a ham fest. I plan to use it on a general purpose dipole antenna with an MFJ 902 Travel Tuner. Since neither the rig or the tuner has a SWR meter I want to hook one up between them. My question is where do I hook the co-ax from the antenna--to the tuner or to the meter?
    Thanks and 73
    Dennis
    KB1ORM
     
  2. KA9VQF

    KA9VQF Ham Member QRZ Page

    That depends,... to check out the antenna you simply wouldn't put the tuner in line at all.

    Once you have checked the antenna out and made notes of your SWR on all the bands you plan to work later you would put SWR meter between the radio and the tuner, that way when you adjust the tuner you would read the SWR the radio sees not the actual SWR to the antenna.

    Once you have made notes of the settings for each band you use with the tuner {commonly called a cheat sheet} you really should be able to remove the SWR bridge if you want.

    Personally since I have an abundance of SWR meters I keep one inline all the time. Of course my tuner has one built in too. My main rig is a TS-820S and with the tube finals I really don't need a tuner much, by loading the rig into the antenna I get a pretty good match with out a tuner, but sometimes I like to use my TS-120S and since it has transistor finals I like to use the tuner into the semi-resonant hunk of wire in the sky here.
     
  3. WA7PRC

    WA7PRC Ham Member QRZ Page

    If you plan on using the rig with an antenna cut for 6m, skip the tuner and connect the VSWR bridge between the rig & antenna. Antennas such as the MFJ-1776B or MFJ-2206 sound ideal for your use. Or, you can easily build something for much less coin.

    73,
    Bryan WA7PRC
     
  4. K0RGR

    K0RGR Premium Subscriber QRZ Page

    A 'general purpose dipole'...?

    A dipole is nominally a single band antenna. They will work on their 3rd harmonic, so a dipole cut for 40 meters will present a decent match to coax feedline somewhere in the 7 Mhz. band, and also in the 21 Mhz. band - the third harmonic. It will not present a decent match to coax on any other bands.

    A tuner can be used to stretch an antenna to work on other bands, within limits. And, on those bands where the SWR is naturally very high, the tuner may not be able to match it at all. And, if it does, there will likely be large losses on the coax and in the tuner itself.

    Feeding the antenna through open wire feeders could alleviate these issues to a large extent, because the balanced feeders, properly used, have very low loses even at high SWR. But that will require a balanced tuner or a good balun to convert from the unbalanced coax output of the tuner and the balanced feedline.

    A friend of mine had as his only antenna a low 40 meter dipole fed with RG-58 and a 1:1 balun. He was able to make it work on all the higher bands. Then, one day, he got a Hustler vertical, and he thought he'd died and gone to heaven.

    Back to your original question, though. You care what the transmitter sees for SWR, so you always put the SWR bridge between the transmitter and the next thing downstream - in this case, the tuner.
     
  5. KB1ORM

    KB1ORM Ham Member QRZ Page

    I made a poor choice of words. I should probably have said "long wire antenna" instead of "general purpose dipole". In any case I now know where to put the meter and the tuner.
    Thanks and 73
    Dennis
    KB1ORM
     
  6. K4EEZ

    K4EEZ Ham Member QRZ Page

    From Radio >>> RF out >>>RF in (Tuner) >>> RF out (normally marked ANT) > to ANT.

    Or

    From Radio >>> RF out >> RF in (SWR Meter) >>> RF out >>> RF in (Tuner) RF out > to > Ant.

    Or

    From Radio >>> Rf out >> RF in (AMP) RF Out >>> RF in (Tuner) RF out > to > Ant.

    Or

    From Radio >>> Rf out >> RF in (SWR Meter) RF Out >> RF in (Amp) RF Out > to ANT.

    Or

    From Radio >>> Rf out >> RF in (SWR Meter) RF Out >>> RF In (Amp) RF Out >>> RF in (LOW Pass Filter) RF Out to > ANT.

    Or

    From Radio >>> Rf out >> RF in (SWR Meter) RF Out >>> RF In (Amp) RF Out >>> RF in (Tuner) RF Out >> > RF In (LOW Pass Filter) RF Out to > ANT.

    Whatever you plug IN, there also must be an OUT
    in is normally marked as RF in or TRANS this wound be an Input.

    RF out or ANT I'll let you guess this one... :D

    its like hooking up a stereo system EG
    Tape/Tuner/CD>>> EQ >> AMP >> Speakers

    Each device has input and output, just remember what goes in must come out
     
    Last edited: Jun 10, 2010
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