Of Manual Tuners, Specifically the MFJ-948

A couple of days ago I mentioned an MFJ-948 manual tuner or something comparable as being a nearly essential piece of ham radio gear.  That lead me to some youtube-falling-down-ratholes, and two videos came out on top: 

Hidden Features of the MFJ-948 (24 minutes) 

and

Best Manual ATU Tuning Method (14 minutes)

Even though I've had mine for about seven years now, I still learned a couple of new tricks from the first video.  As for the second video, I've always had a nagging suspicion that there was a better way to adjust things.  In the end however, he comes to much the same method as I've been using.  Here are the steps:

1. Turn off your transceiver's internal tuner.  Set it to the band, frequency, etc. you're targeting.  Then set to a nearby empty frequency so that you can hear the steady background noise.
2. Set the Antenna & Transmitter controls to their midpoints.
3. Crank around on the inductor switch until you hear the loudest signal.  Now leave it alone.  Above all, never change the inductor switch while transmitting.  That can cause arcing inside the tuner.
4. Now dial around with the Antenna & Transmitter controls.  If no differences can be found, leave at midpoint.
5. Turn the transmitter power to minimum, send in a signal (AM or FM carriers, or a digital tone).
6. Iteratively, tune the Antenna & Transmitter controls to minimize SWR.  Tune the Antenna knob first, it's generally more of a coarse control.

The alternate method in the video works too, but it's just too fiddly.  Still, interesting to watch, good to know that the common received wisdom is probably about the best way to go.

For shortwave listening, a tuner can help as well.  Here's a video showing how that works.  It's 17 minutest total, but the real action is packed into 2 minutes starting at the 12 minute mark.  TLDW version: Apply steps 1 thru 4 above, then get on with listening.

Anyway, the MFJ-948 antenna tuner has its charms.  It's far too bulky to take backpacking, and in the field where you want an antenna with known characteristics to just work at the push of a button, automatic units are usually the right way to go.  On the flip side, for at-home use (or maybe when car camping), all of the information from the crossed-needle gauge along with all of the features make the 948 an antenna experimenter's delight.

You can download the manuals from the manufacturer, and even order directly from them.  However, you can usually get a substantially better price from various online retailers or from vendors at hamfests.  This is one case where it pays to shop around a little.

Say hello to my friend, R.F. Burns.  I swear, MFJ is the closest real-life thing to ACME Industries in existence.