Tag Archives: Shortwave and Sci Fi

Mike IDs a Hallicrafters Skyrider in Avengers scene

Avengers-Ultron-Hallicrafters-Radios

In response to my post about finding a glowing Hallicrafters radio in a scene from the Avengers: Age of Ultron, SWLing Post reader, Mike (AC4NS) writes:

“I put the pic in Lightroom and pulled it out of the shadows.

It is definitely a Skyrider and not an SX-28.”

Avengers-Ultron-Hallicrafters-Radios-1024x429

Wow–I’m amazed there was enough information in that photo to pull it out of the shadows! You can see the silk screening and the SEND-REC. switch in the lower right corner.

Again, here’s my Hallicrafters SX-24 Skyrider Defiant for comparison:

My Hallicrafters SX-24

I know why they used a Skyrider in the film; the warm glow of the dials and signal meter were simply irresistible! (At least, they are for me!)

Thanks for helping ID this, Mike!

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Avengers ‘Age of Ultron’ scene: is that a Hallicrafters receiver?

Avengers-Ultron-Hallicrafters-Radios-1 With the recent posts about shortwave radio in films (Star Wars and Star Trek), I remembered a scene from Avengers: Age of Ultron where I thought I spotted a vintage Hallicrafters receiver.

In the scene, Hawkeye (Jeremy Renner) is using an “old school spy method” to find the whereabouts of Black Widow (Scarlett Johansson). I remembered Haweye sitting in front of a 1940s era radio.

This weekend, I found the clip from the movie (first time I had seen it since the theatre) and sure enough, I’m positive this is a Hallicrafters. Click on the images above or below to enlarge.

Avengers-Ultron-Hallicrafters-RadiosI can’t quite determine the Halli model, though–can anyone ID it?

The images aren’t the best: the scene is dark and the radio at quite an angle. Still, there’s no mistaking that Hallicrafters glow.

My Hallicrafters SX-24

My Hallicrafters SX-24

I think there’s a good chance it’s the same model I have in my radio shack: the Hallicrafters SX-24 ‘Sky Defiant‘–but I can’t quite confirm. Perhaps it’s an SX-28?

Can anyone provide a positive ID? Please comment!

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How Bob McGwier used a Cray-2 supercomputer to decode a ham radio transmission heard in Star Trek IV

Startrek4-MoviePoster-SmallIn response to our recent post with a message to us from Star Wars sound designer Ben Burtt, SWLing Post reader, David Guilbeault, comments:

Here’s a similar story that circulated on the Internet around 1990 (pre WEB!). I worked in packet switching at that time and was very impressed with Bob’s achievement (even with a CRAY to work with) .

I reached out to Bob McGwier (N4HY), who is a Facebook friend, and he has kindly given us permission to share his message again here and with a few new comments:


Star-Trek-IV-Cap

Decoding HF packets in Star Trek IV

Originally posted on December 4, 1989 by Bob McGwier (N4HY)

Several months ago, Harold Price, NK6K, challenged me to demodulate what he thought might be HF packets in Star Trek IV.

Chekov-Uhura-Star-Trek-IV

During the scenes where Scotty is valiantly trying to beam both Chekov and Uhura back from the U.S.S. Enterprise, where they have been stealing Nuclear vessel high speed photons, Scotty is having a hard time hearing them.

Scotty-Star-Trek IV

Listen to the audio clip by clicking here or using the embedded player below (target sound is at 5 seconds):

One of the sources of interference is what appeared to Harold to be HF packet. Always being one to rise to a challenge, I took on the job of doing some fancy Digital Signal Processing footwork. Almost from the first I was certain that it must be an HF packet since my very first demodulator attempt clearly revealed flags before the start of a frame and end of frame was also clear. I knew it was HDLC of some variety.

Several things impeded the effort, including Scotty’s voice on top of the packets, some SSB from 20 meters was also nearly on top of the signal. All of this had to be filtered out. I spent an hour of time on the Cray-2 at work and used the fanciest FSK demodulator I could write and I finally had noisy baseband signal plotted on paper in front of me. I did my best to get an integral number of samples per baud as the signal was very noisy, and though the bits could be made out by eye, I could tell that it was going to take another hour of Cray-2 time to get the clock recovered and to make good bit decisions. In a couple of places, HDLC showed me what were clearly bit errors, and these could be done by eye as well.

A Cray-2 operated by NASA. (Source: NASA)

After the filtering, and building a demodulator for the badly mis-tuned signal (almost 900 Hz below), I took the bits to Phil Karn, KA9Q and he decoded the NRZI data and proved beyond a shadow of a doubt that it was indeed an HF amateur radio packet. It was WA8ZCN-0 sending an RR for NR-3 to N6AEZ on 20 meters. I got Bill Harrigill, WA8ZCN on the phone and he agrees that it was probably him.

Thanks Harold for the challenge and Phil for the help.

Bob N4HY

P.S. A Cray-2 is about 50% faster than the fastest Pentium-Pro computer available today.

Again, keep in mind that the message above dates from 1989! This past week, Bob added the following comment when I contacted him:

The Cray Supercomputer on which the work was done was being operated on behalf of the National Security Agency by my research institute.

I received permission to “to test optimal algorithms for software decoding of FSK transmissions” and this was my test case!!!!

That is why Phil Karn was decoding the AX.25 bits by hand. I did not have permission to develop link layer protocol code, though I tried.

A few years later when half the bad guys in the world seemed to be using AX.25 and cheap ham gear I said “See, I told you so several years ago and you didn’t listen”.

I used that transmission in so many different ways I no longer remember them all.

That’s fantastic, Bob, and so great to know the back story on your decoding process! Thank you again for sharing this with us!

Star Trek fans can find the scene Bob references starting around time mark 1:12 in the film.

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