Realistic DX-160 Shortwave Receiver

A 1970s Radio Shack solid-state shortwave receiver, bought from a ham who was downsizing, then aligned and given a proper antenna jack, with plenty of help from the local ham breakfast crowd.

A Realistic DX-160 communications receiver with its silver front panel, lit dial and S-meter, next to its matching gray Realistic speaker on a workbench — The DX-160 and its matching Realistic speaker

The Realistic DX-160 was Radio Shack's solid-state shortwave and AM broadcast communications receiver. I bought mine from a ham who was downsizing. It needed a little work, and some very knowledgeable people helped me learn how to do it. This page follows that: the alignment, a better antenna connection, and the test gear that came along.

I run it from my MLA-30 magnetic loop. The same loop also feeds my SDR through an active splitter, so both radios can listen to the same antenna at once.

Listening

On March 8, 2026 I was tuning around "old school" and heard WWCR, the Overcomer Ministries station out of Nashville, Tennessee, on 5935 kHz.

Alignment

At a breakfast meetup of the Henderson Amateur Radio Club (HARC), Larry, K7MLG, gave some of us a primer on aligning a radio. I took that home and aligned the DX-160 that same afternoon, both the IF and the RF stages, using an Eico 320 signal generator (made sometime in the 1950s or 60s), an oscilloscope and a sensitive digital voltmeter.

A restaurant table covered with test gear: a Tektronix oscilloscope, a gray Eico signal generator and a radio chassis open with its circuit board showing — Alignment class at the breakfast table: signal generator, oscilloscope and an open radio chassis

A garage workbench with the DX-160 on a mat, an Eico signal generator, an oscilloscope and two digital meters around it — The alignment bench: Eico 320 signal generator, oscilloscope, meters and the DX-160

Two short videos I made while doing it:

A proper antenna jack

The DX-160 only came with screw terminals for the antenna. To connect my 50-ohm mag loop I had been using a DIY BNC-to-screw-terminal adapter, and that created an impedance mismatch. So on March 25 I decided to install a panel-mount BNC connector with a 9:1 balun.

The BNC fit in an unused factory hole hidden behind the serial number sticker. I warmed the sticker with a heat gun, peeled it off, and moved it to the bottom panel. The connector fit almost perfectly in the hole.

A DIY adapter made of two spade terminals on twin wire leading to a pair of binding posts with a BNC jack — The old way: my DIY BNC-to-screw-terminal adapter

A small toroid core wound with green, orange and white wire, with heat-shrink-covered leads, on a workbench — The 9:1 balun, wound on a toroid core

The rear panel of the DX-160 seen from inside, with a BNC jack in the hole where the serial number sticker used to be, next to the screw terminals — The new BNC in the hole that was under the sticker, next to the original screw terminals

Inside the DX-160 chassis: the balun toroid and its colored wires connected near the new BNC jack, above the circuit board — The balun wired in behind the BNC

The underside of the DX-160 with its rubber feet, ventilation slots and the relocated serial number label near the rear — The serial number sticker, moved to the bottom panel

The back of the DX-160 with the BNC jack connected to a black coax cable, and the Realistic speaker beside it — Finished: the back panel with coax connected to the BNC

With the retrofit done, that same evening I tuned to WWV, the U.S. time-signal station, on 5000 kHz. It came in strong that night:

A Heathkit VTVM

When I aligned the DX-160 I didn't have a vacuum tube voltmeter (VTVM), so I got by with a sensitive enough digital voltmeter. Then someone kindly gave me a Heathkit VTVM (Model IM-5218) from the late 80s, in pristine condition. I took it to the Tuesday breakfast, where K7MLG helped me give it the once over.

A small VTVM held by a hand on a restaurant table, with a signal generator, a variable transformer and an orange digital multimeter beside it — Looking the VTVM over at the Tuesday breakfast

The Heathkit VTVM on a cutting mat with its probe and cable, a spare plug and the Heathkit manual — The Heathkit VTVM with its probe and manual

It only needed a slight calibration, which I finished on June 12.

A workbench with the VTVM, an orange digital multimeter, a red variable transformer and cables laid out for calibration — The calibration setup

The VTVM chassis with its vacuum tubes, a power transformer and a blue electrolytic capacitor, sitting on a red cloth — Inside the VTVM: the vacuum tubes

The VTVM chassis on its side showing a large rotary switch wired with many colored wires — And the rotary switch

The probe

The meter also needed a probe. Larry, K7MLG, donated a used RCA WG-289 probe for the project. RCA made it for its own meters, so it had to be retrofitted for the Heathkit: I replaced its screw-on connector with a ¼-inch audio plug and added a ground wire with an alligator clip.

It's common to replace the meter's ¼-inch jack with a BNC connection. But the VTVM was in such great condition that I wanted to keep its original form.

The finished probe: a gray pen-style probe with black cable, an alligator clip on a short lead and a quarter-inch plug — The finished probe, with the ¼-inch plug and the ground clip

A close-up of a knurled connector on a black cable next to the tip of the gray probe on a cutting mat — The old connector beside the probe tip

Why a VTVM?

A vacuum tube voltmeter is designed to have a very high input impedance when testing circuits. That means the meter doesn't load the circuit and change what it's measuring, which is why it's generally preferred when aligning AM radios.

Links

Video: tuning WWCR Video: WWV time signal Video: testing with a signal generator Video: zero beat with an MFJ-259B Random Gene on YouTube