Hallicrafters SX-110 receiver

Printable manual for this radio

I originally bought this radio at a hamfest in the Seattle area, for about $100. It was going to spend most of its time as a SWL rig, and might be a prop in a short film I was thinking about making. The short film still hasn't happened, but the radio does fine duty as a SWL receiver in the living room.

Technical description

This radio is a late 1950's era tube receiver. It uses a single-conversion superheterodyne circuit, and tunes from 538 kHz (low end of the AM broadcast band) to 34 MHz (just above the 10m ham band into what I think is military spectrum) in four bands. It's capable of receiving AM and CW, with a widely variable pitch in CW. It's got a crystal filter for receiving in either mode, as well as manual or automatic sensitivity, three different tone settings and a noise limiter. There's also an S-meter and an adjustable antenna loading capacitor. It has antenna terminals for balanced and unbalanced antennas ranging from 52 to 600 ohms, and speaker terminals for 3.2 ohm or 500 ohm speakers. Note that the radio doesn't have a speaker built in, you have to supply one. Unpowered computer multimedia speakers make an excellent choice if you're not willing to lay out the cash for an original matching Hallicrafters accessory speaker.

Using it

The radio is relatively easy to use, with one major caveat (probably only useful to those of us who have never been exposed to this kind of radio before): the tuning indicators are entirely unclear. If you read the manual, it becomes clearer how it works, but I was unable to tune the radio at all due to the strange (to me) combination of bandspread and main tuning.

The way it works is like this: the main tuning is just what it seems. You use this dial to find approximately where you want to listen. Once you're there, the bandspread acts like a fine-tuning control, and is much easier to use when getting right on the frequency of a station. The setup is non-intuitive, in that the bandspread needle needs to be all the way over to the right in order to accurately read the main tuning indicator. If it's centered, or off to the left at all, the main tuning dial is offset from its displayed frequency by some amount, depending on the band selected and where the bandspread indicator is.

Aside from that unaccustomed mannerism, the radio is quite straightforward. It's also surprisingly sensitive, pulling a good many hard-to-hear stations with only a room-loop antenna (just what it sounds like -- a loop of wire run around the ceiling of the living room). My particular radio is also in need of alignment, as the indicated tuning is between .5 and 2 MHz off, depending on where in the frequency band you're listening.

Now that I'm used to it, I find I quite like this radio. The sound with an attached unpowered computer speaker is fairly good, far superior to my Icom 746 amateur radio transceiver, but still the familiar low quality of AM, compounded by fading and static from coming across the shortwave bands. However, with the three tone positions, it's possible to find a position that's quite listenable, especially with stronger signals. The different selectivity options also help with this (the radio has two different crystal filters, as well as the normal no-filter position).

Although I primarily use the radio to listen to AM broadcasts, it's also capable of receiving CW. I've tried this on one or two occasions, and it's not easy to do. The filters are wide enough that anywhere I can find a strong signal, I get two or three stations at once. In addition, the tuning, even with the bandspread control, goes so fast that it's very hard to center a single CW station.

Being a tube radio, this receiver does take a few minutes to warm up. The inital warmup on my radio takes about 40 seconds until I start hearing static from the speaker, and it finally stops drifting around 20 minutes in. Until it's warm enough, you have to keep adjusting the frequency up in small increments. The unit that I have is still in very good condition, as you can see from the heading photograph. The only defect I've been able to find is the chipped rim on the bandspread knob, and I guess I'm not enough of a perfectionist to care about that.

There's lots of information out on the web about these radios. One of the sites I just found recently is this one, at dxing.com. A quick Google search should turn up quite a bit of good stuff.

Created by Ian Johnston. Questions? Please mail me.