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How to use a Manual Tuner

Discussion in 'Amateur Radio News' started by KM9G, Aug 25, 2021.

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  1. KM9G

    KM9G Premium Subscriber QRZ Page

    Today I play with the same antenna, same radio, but a different tuner. Let's demystify manual tuners!
    N3ODT, VK5FUSE, KI7WGA and 16 others like this.
  2. WJ6F

    WJ6F Ham Member QRZ Page

    Great video! These tuners tend to look scarier than they actually are.
    W1YW, KC1OSJ and M1WML like this.
  3. AI5DD

    AI5DD Premium Subscriber QRZ Page

    I use an MFJ full legal limit manual tuner with a roller inductor. Best tuner I've ever used and I prefer a manual over the automatics I've used.
    K4FMH, MW1CFN, W8VIJ and 2 others like this.
  4. NU4R

    NU4R Ham Member QRZ Page

    M1WML and KM9G like this.
  5. AE0RS

    AE0RS Ham Member QRZ Page

    You might want to turn off Noise Reduction when you're...listening for noise :D

    I wish instead of letters and numbers, they had max/min or percentages of capacitance and inductance since you're supposed to try for a more fully-meshed capacitors and somewhere-in-the-middle inductance. I think that would take out some of the mystery of MFJ tuners since you know what turning the knobs are actually doing with respect to reactance, inductance, capacitance, etc. in your system.

    Here's the manual for this unit:

    I love my ancient MFJ tuners - they will tune a wet noodle and get -15db FT4 signal reports.
    KF5KWO, W8VIJ, WG5ENE and 3 others like this.
  6. KM9G

    KM9G Premium Subscriber QRZ Page

    Those roller inductors are awesome. They just feel so good.
    W8VIJ and AI5DD like this.
  7. W3AMT

    W3AMT Ham Member QRZ Page

    I use my Johnson Kilowatt match box with a 145 foot long wire tunes it early and my kilowatt is happy.
    W3KKO, M1WML and KM9G like this.
  8. N0NC

    N0NC Premium Subscriber QRZ Page

    It's always a good Idea to open you MFJ manual tuner (to see if the manual is correct) to check which setting 0 or 10 is maximum capcitance, and maximum inductance. My oldest mfj 989c has minimum capacitance at zero and maximum at ten (or in the case of inductance zero or some high number). Part way through production that was all changed by a W8JI to make maximum at zero and minimum at ten so that they tuned like amplifiers did, (the way he felt was correct). The old tuners, Heath, Dentron, ect, followed the older pre-W8JI standard, so I have had some of both. I always open them up and check though. Obviously the tuner indicated in the above link is a newer model since it has max at zero.

    73, Chuck
    G0CIQ, W9BRD and M1WML like this.
  9. WE8TOM

    WE8TOM Premium Subscriber QRZ Page

    If you run more then 10 watts, check if a tuner helper (but not hamburger helper) device will work with your rig. I have a Tuner Tamer (from the ham made gear forum) for my 7300. Push the button and it will kick the power down to 10 watts and have the radio generate a tone. It's a latching button so your hands are free to work the tuner. When you turn it off it puts your power and mode back to where it was. Also keeps you from "accidentally" sending out a 100W tone over a distant QSO. There are many DIY/Ham made/commercial devices out there, mostly for Icom. Not sure about other brands of rigs. It's well worth the price for it's convenience.
    G0CIQ, KA8VNG, KM9G and 1 other person like this.
  10. N0NC

    N0NC Premium Subscriber QRZ Page

    WE8TOM, I always use a manual morse key and reduce the power manually to tune. Of course the two transceivers that get the most use at my shack have a power control knob on the front panel. Since the 7300 is a SDR, can the multi use knob be reprogarmmed to adjust the power level, or must you always enter the menu?

    73, Chuck
    G0CIQ, KG5WDD and M1WML like this.

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