How I do tune a tube radio into an antenna tuner

Discussion in 'General Technical Questions and Answers' started by VE3PCD, Sep 5, 2010.

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  1. VE3PCD

    VE3PCD XML Subscriber QRZ Page

    Hello all !!

    Can someone please tell me the correct procedure to tune the FT-101E into the Pulstar AT1KP tuner?

    I cant seem to be able to get the swr down, I tune the radio but then unable to get tuner correct the swr....What am I doing wrong?


  2. AF6LJ

    AF6LJ Premium Subscriber QRZ Page

    By first tuning the tube radio into a dummy load then tuning the tuner with the radio connected to the tuner.

    One of the nice things about some of the MFJ tuners is they have a built in dummy load....
    It's just a switch throw away.
  3. KD0CAC

    KD0CAC Ham Member QRZ Page

    I am posting more to see than answer , but have some idea's .
    I found with working a club station how to tune on frequency and not QRM others on that frequency .
    Have a antenna analyzer in the circuit with a switch that would be to switch from radio to analyzer , then watch the analyzer while tuning , the tuner on the exact frequency you want to work , now that you have the tuner tuned , turn switch back to radio & tune the radio .
  4. KE3WD

    KE3WD Ham Member QRZ Page

    Here is one method, tried and true, with the idea of not getting into territory that can damage output tubes and components in mind:

    Use of a 50 ohm Dummy Load and an antenna switch arrangement that allows you to switch between Dummy Load and Antenna Tuner at the Tuner's input can really help.

    Tune up the '101 into the Dummy Load first.

    Now you have the '101 all set to yield full power into 50 ohms.

    Reduce the power of the '101 and switch over to the antenna tuner, and, as rapidly as you can, tune the tuner. It is better to do short transmissions and tune the tuner, stop transmitting for a sec or two and repeat the short tuning transmission picking up where you left off IMO.

    Can't stand those !#$&%$ "half hour" tuneups on the bands, and neither can your finals or the components in your tuner.

    Writing down the settings for a certain band area so that you can place the tuner controls to those settings when returning is a very good idea. Then you can spend less time in the tuning to get to the optimum point since the controls will already be somewhere near the right places. Some hams place paper stickers at those points on the dials of their tuners (and linear amps) as reference points for the various bands they use, a fine idea for spending less time on the tuneups and more time on the air as well as a good way to have some reference points that would indicate to you any problems that can happen to an antenna system before such can damage components in the tuner - or even the rig itself.

    If you don't have a good 50 ohm Dummy Load that can handle the output power of your '101, now is a good time to start thinking about picking one up, along with that antenna switch. Every ham should have a good Dummy Load handy.
  5. KD0CAC

    KD0CAC Ham Member QRZ Page

    Sue beat me to it .
    I have a further question .
    If there may be some discrepancies between the dummy load , tuner , feedline and antenna , would the radio tuned into the dummy be a little off ?
    Probably close enough though , many ways to skin a cat .
  6. AF6LJ

    AF6LJ Premium Subscriber QRZ Page

    It wouldn't be off when tuning the tuner for lowest VSWR.
  7. KD0CAC

    KD0CAC Ham Member QRZ Page

    I was referring to tuning the radio into the dummy load .
    But I have not owned or operated a tube radio yet .
    Just got two amps , non operational and repairing , a Heathkit SB-201 and a Collins 30L1 .
    After getting my ticket , I thought that having to learn ham radio on older rigs would be a better learning experience , because of the solid state rigs turn on and go , instead of what had to be known and set manually with the older rigs ?
  8. AF6LJ

    AF6LJ Premium Subscriber QRZ Page

    I believe when you have an older tube radio, especially one well metered you do learn more.
  9. AG3Y

    AG3Y Ham Member QRZ Page

    A major un-answered question. What mode are you using to tune your setup? Of course, you need to use a continuous carrier to tune the rig, and the auto-tuner needs to see a continuous low level carrier in order to tune for lowest SWR. (probably around 5-10 watts) Are you attempting to tune the antenna tuner with a low-level continuous signal, or are you assuming that you can tune it with a voice signal in SSB ?

    That will not work. You MUST use a low level continuous signal!
  10. K0RGR

    K0RGR Premium Subscriber QRZ Page

    Yes, back when radios glowed, a dummy load was a fairly essential shack accessory, and this is part of why. A dummy load is the right way. The wrong way is to get the transceiver tuned up well enough to put out a signal that you can use to tune the tuner, then go back and refine the tuning on the transmitter. However, after you've tuned things up a few time, you'll have some idea of what the setting should look like on both the tuner and the transmitter, and you'll be able to get fairly close without much tuning.

    It's always a good idea to keep track of your settings for each band, just for this reason. It will also tell you when something changes, which may be an indication of a problem somewhere.

    Another option would be to use an SWR analyzer or a noise bridge to tune up the tuner before tuning the transmitter. Noise bridges were also fairly popular in the latter tube days.
  11. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    A good dummy load is a ham station essential.

    In a pinch, a 1000' spool of RG58 coax makes a pretty good dummy load.

    Actually, it makes a great dummy load at VHF!
  12. W0UZR

    W0UZR Ham Member QRZ Page

    If you don't have a dummy load, then turn the CARRIER down to where you have just 100 milliamps on transmit. Then tune the Plate and Load over and over for best output while keeping it at 100 milliamps. Then key up and tune the tuner for lowest SWR. After you get the best SWR on the tuner, then increase the drive and tune the radio and retune the tuner.

    OK, NOW, if you are unable to tune the tuner after all that for lowest SWR then two things might be happening.....

    1. Your SWR is way too high and the antenna needs to be worked on to get it down. And if that is not the case then

    2. When you tune one knob on the tuner for lowest, then go past the dip turning the knob in the same direction, and the SWR will go higher, and tune the other knob and see if it will drop further. If it does, then go further turning that knob in the same direction and the SWR will read higher, then retune the first knob again and it should drop again and by this time it should be close to flat. This is what I have to to with my Drake Tuner to get it flat.

    And if tuning further in the same direction letting the SWR go back up does not work, and tuning the other knob doesn't make it go down more, then turn the knob in the oppisit direction which should be BEFORE YOU GET TO THE DIP, where the SWR goes back up some, and then tune the other knob, and go past the dip and let the SWR rise some and then retune the first knob again and it should drop a quite a bit more.

    This doesn't sound like it's right, but with this meter I have, that's the only way I can get mine tuned. It might be the same with yours.
    Last edited: Sep 5, 2010
  13. W5HTW

    W5HTW Ham Member QRZ Page

    Being sure you know this - those final tubes in the FT101E are very easily destroyed and very expensive to replace. Tuning ten seconds out of resonance will probably arc one or both over. Then you will have to spend $100 to buy a new pair.

    That said, we'll address the question. First, if your tuner has a built in dummy load, use it.

    Preset the controls to the right frequency, which includes the Plate and Loading controls and the preselector.

    Turn the Drive/carrier all the way down. Zero.

    Switch to TUNE. Or, to CW if you have a key. But Tune will work.

    Slowly increase the Carrier control until the plate current (be sure you are monitoring plate current, and not RF output) goes up a little.

    I always set the radio's Load control to minimum, but setting it at the 50 ohm spot is ok.

    Now rotate the Plate control for a dip.

    When you have the dip, increase the Drive/Carrier control to get perhaps 100 ma plate current on the meter. (That is Ip, by the way.)

    Now be sure you have a noticeable dip by rotating the Plate control each direction just slightly and be sure plate current rises.

    Increase the Load control to the preset position.

    Pause. Switch to receive and let the finals cool a good 30 seconds.

    Switch back to TUNE and start increasing the carrier control until you get about 150 ma on the plate meter.

    Recheck the dip. It should still be good.

    You are tuned up. Switch to receive and let the tubes cool.

    Now switch the tuner in line. You can rotate those controls for maximum received noise and be fairly close.

    Set the tuner's meter switch to SWR or Reflected, however it is worded.

    Once again, reduce the Carrier control on the FT101, but not all the way.

    Switch to Tune (or CW) again, and rotate the "transmitter" control on the tuner for minimum reading. Watch the plate current meter on the 101 so the current does not rise above 150 ma.

    I don't know your tuner. If it has a roller inductor, you can also tune that for minimum SWR as well as the Antenna control. Make adjustments as quickly as you can, and keep plate current below 150 ma by reducing the Drive/Carrier.

    This should get you there.

    Some tuners will not reduce SWR to anywhere near zero, depending upon the antenna being used. Wide range manual tuners may tune 30 to 1200 ohms reactance, but there are many that will not cover that range.

    Most of us who use tube type radios regularly actually used them by necessity 'back in the day' so the Plug and Play radios weren't available. We were forced to learn. Amateurs today have not had that requirement, so when they try a tube output radio, including an amp, they are often lost. In those cases, they should try to find a local ham with experience in tube transmitters, to give them some hands-on training. This is especially true with transmitters or transceivers using sweep tube ouput stages, as those tubes arc very easily, self destructing in a couple of seconds.

    Another factor is so many of the FT101's were 'CB-ized." Driven very hard and put up wet. It was one of the most popular illegal 'CB' rigs around, and many thousands never saw a ham band. That resulted in tremendous strain on the final compartment, and often the driver as well. Many of them were run at well over the 40 watts AM (Input, not output!) at which they were rated, with incredible final dissipation.

    I was fortunate to have a couple of FT101E's (one was an EE) that had never been run on CB, so operating them within their factor parameters made them highly reliable, even with the old sweep tubes.

    Oh yes! Be SURE you have the manual, you read it, and understand it. It can be downloaded at several places. Don't operate the rig without reading the manual!

    Good luck with yours

  14. KD7MSC

    KD7MSC Ham Member QRZ Page

    I have used a 100 watt light bulb in a pinch (and just for fun too).
  15. VE3PCD

    VE3PCD XML Subscriber QRZ Page

    I want to say thank you to all who responded, I am not really surprise how many good responses I received. The main reason why I decided to get the FT-101E is that it will allow me to experience what it was like years ago when tube radios ruled the HAM universe. I am now able to properly tune my rig.


  16. AF6LJ

    AF6LJ Premium Subscriber QRZ Page

    I knew someone who had an FT-101 wish I had one.
  17. NO2A

    NO2A Ham Member QRZ Page


    I`m sure there`s one waiting for you on e-bay............................:p
  18. W8JI

    W8JI Ham Member QRZ Page

    Assuming you have a tuner and a high SWR on the antenna system without the tuner, it is imperitive you tune the FT101 into a good dummy load as a first step.

    A light bulb will not work.

    Here are the steps:

    1.) Load the Ft101 into a dummy load that you know is 50 ohms.

    2.) Reduce the power until it is down to the minimum amount that allows you to adjust the tuner. The amount of power depends on the tuner and the meter in the tuner.

    3.) Adjust the tuner for minimum SWR.

    4.) Increase power without retuning the radio, and make sure the reflected power is minimum.

    That should be all you need to do.

    73 Tom
  19. KL7AJ

    KL7AJ Ham Member QRZ Page

    I'd just tune the tuner for maximum receive noise, and then tune the transceiver as if you were tuning directly into a dummy load. Close enough for government work.

  20. W8JI

    W8JI Ham Member QRZ Page

    I don't think so Eric. That might result in a 2:1 SWR or even higher.

    Better he does things the right way, and adjusted the radio into a 50 ohm load. Then he can reduce power and adjust the tuner properly for lowest SWR.
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