HEATHKIT SA2060A TRANSMATCH REVIEW WITH INTERNAL PHOTOS
  

The Heathkit SA2060A rivals commercial antenna tuners on features and performance. It includes an excellent Wattmeter with two indicators. An antenna switch and internal balun for balanced line completes the impressive list of features. It covers all bands from 160 to 10 meters including WARC.

The meters are fantastic. The sampling line box is factory built and calibrated. It does not depend on the kit builder to get it right. NEVER ADJUST THE TRIMMER SHOWN BY THE RED POINTER IN THE PHOTO. It is a factory only adjustment. You will screw up the calibration.

The wattmeter seems to agree reasonably well with my digital wattmeter. TWO METERS are absolutely essential for getting the match right. Forward Power cam be doing all sorts of strange things when you are staring only at a Reflected Power meter. Tune this for maximum Forward and minimum Reflected at low power levels, 20 watts or so. NEVER TUNE ANY TRANSMATCH AT FULL POWER! NEVER ADJUST THE ROLLER INDUCTOR AT FULL POWER! This is the number one cause of transmatch failure. Use the capacitors to get to minimum reflected. Then run up the power level and look again. Final tweaks to the capacitors only. This prevents pits and burns on the moving parts of the roller inductor. Think of it as a continuously variable inductance switch. That should never be moved during transmit either.

The slickest way to adjust a transmatch is to use a device like the MFJ-212 or the Ten Tec 1051.

Heavy metal strap is used for some of the wiring. Be careful of lead dress so that this strap does not get near anything else. This also is a function of original builder's skill and care. Internal photos show the quality of components in this transmatch.

The antenna switch functionality is confusing. It says BYPASS on the front panel. This function does not really bypass the transmatch section of the SA2060A. It routes the input signal from the transmitter to one jack on the back panel that you could use for a dummy load. All others go through the tuner to the jacks on the back of the box.

The Heathkit SA2060A was reviewed in QST and other magazines. On unbalanced low impedances for 160 and 80 meters, the losses increase, even without the internal balun. They are comparable to similar designs of T match though. Power rating (without the balun) is easily full legal power, if the SA2060A is correctly built and serviced.

The losses are more than the E F Johnson Matchbox for balanced lines when the SA2060A is operating off the internal balun. Likewise for 10 meters, due to the limitations of the internal voltage balun. I do not use open wire feedline. I have tested the balun using carbon resistors of various values using my MFJ-259 analyzer. The performance on 160 meters and 15 and 10 meters on the ends of the spectrum indicate some unbalance and loss is probably. This increases losses and increases heating when using high power. If you use this transmatch, I recommend a separate current balun (located near the antenna) if possible. This is one of the weak points.

The other weak point is the internal antenna switch. If you operate the switch often, it will wear out the detents or contacts as they wipe off the plating. I use external antenna switches to avoid this problem. The bypass function does not work the way I would have preferred anyway. The Dentron MT2000A has a true bypass function.

ADJUST THE ROLLER INDUCTOR CONTACT TENSION TO PREVENT FAILURE IN THE SA2060A

Hardware is a problem of the original builder. Check, but do not over tighten, all hardware. Problem areas are the capacitor assembly points, the output coax connectors, and the bearing and Belleville washer at the rear of the roller inductor. See the red pointer in the photo below. Be sure the Belleville washer is compressed slightly at all times or the inductor can go open circuit intermittently. Adjust the sleeve to provide tension on the compressible washer, then tighten the set screw shown and you will have no problems.

Service is limited to tightening the hardware and cleaning grundge off the roller inductor components. If pitting occurs, possibly use skotchbrite (green plastic pot scrubber with NO soap). NEVER use steel wool. It leaves conductive shard scattered about. But do not get carried away with abrasion, as the plating is thin.

73,
Janis
AB2RA
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