Posted in amateur radio, living history, military history, Shortwave

World War II Hallicrafters

One of the visitors to my display at last Memorial Day’s FDR event was a lady who was happy to see the Signal Corps. represented there. In conversation, she told me that her father had served in the Signal Corps with the Ghost Army during World War II. We chatted a bit, and she went to go see the rest of the event. This was a common occurrence that weekend, veterans and their families stopping by to thank us for honoring those who had served, and to share stories. You cannot have history, after all, without the story.

The next day, I left my display for a bit to go have lunch with Carol, and upon my return, one of my fellow historians told me a lady had stopped by looking for me. Shortly afterwards, my visitor from yesterday stopped by holding a ziplock bag of ephemera which belonged to her father from his time in the Signal Corps, and that she wished to donate to the museum. I thanked her, and took down her information so she could be properly credited when it appears in a future display.

Upon examination, the bag held some 1950s Signal Corps documents telling me her father served past the war, two pieces of insignia, and two pictures dated 1941 on the back. One was a picture of the squad room our soldier was billeted on, and the other was a radio he owned while there. Intrigued, I set out to identify what model it was.


As a ham radio operator with some boatanchor experience, I recognized the radio as a Hallicrafters. Hallicrafters was one of the first boatanchors I was exposed to, courtesy of a 1983 or 1984 article in CQ Magazine featuring Chuck Dachis, who is the hobby’s expert on them.

The date on the back of the picture was 1941, so I knew the radio was made before then. Consulting the pictures and dates in Radios By Hallicrafters, identification was narrowed down to either an SX-24 Skyrider Defiant or SX-25 Super Defiant. Both radios are very similar in appearance, but the most notable difference to me is that the earlier SX-24 has control settings sikscreened directly on the case for the two controls directly below and to the right of the frequency display, whereas the newer SX-25 only has a single line at 12:00 with the settings on the knobs themselves. Examination of the above picture shows the latter, which makes this unit an SX-25.


I don’t know if the SX-25 was actually used in military service. The next model Hallicrafters made, the SX-28, did see use as the AN/FRR-2.  Available online documentation does not show any indication it was, and I’m guessing that the SX-25 in the picture was the soldier’s personal radio.

In 1941, just before our entry into World War II, the SX-25 was Hallicrafters’ newest model.  When war was declared, the US Army pressed into service all sorts of radio gear, so maybe a few SX-25s did make it into inventory.  Either way, this soldier thought enough of the SX-25 to buy one once he was at his duty station, or bring it from home. If anyone reading this has documentation or other evidence showing that the SX-25 was used as an issue radio, please send me an email.

Just recently, I was at a local Old-School Army/Navy store in Newington, CT called Military Specialties. I was introduced to them by a friend in the early 1990s after having moved to Connecticut for my first electronics job after having come off active duty.  On the shelf in the back among the other collectibles was a very clean looking Hallicrafters SX-25, among a few other vintage shortwave receivers.  Inquiring about it, I learned that Bill, one of the owners, was a shortwave aficionado, and that we both served in the same National Guard unit, albeit 40 years apart.  I bought the SX-25, but there are still some other clean-looking vintage shortwave receivers there for anyone looking.  They’ll probably need a little servicing and aligning, but afterwards they’d be a nice addition to someone’s radio collection.

NEAR-Fest and the Nutmeg Hamfest are this weekend. I’m thinking both would be a good venue to look for the PM-23 speaker that’s in the picture with the radio.

Posted in amateur radio, living history, military history


Being both a student of military history and an Amateur Radio operator, it was natural to combine the two hobbies and put military surplus radios on the air. It was at some time in the early 1990s that one of my elmers gave me my first “green radio” as they are called.  It was a PRC-25, an earlier version of the PRC-77 VHF manpack transceiver I learned to operate in Basic Training a little before then. 

The PRC-25 and PRC-77 weigh about 14 pounds and put out a couple watts of wideband (by today’s standards, ~10 KHz. deviation) FM RF from 30-75.95 MHz. in 50 KHz. steps. I was a Technician class ham at the time, and noted that the radio would operate on the 50-54 MHz. Six Meter band.  At the time Six Meters was not very popular in the NY Metro area because of its close proximity to TV Channel 2, WCBS in New York City. Six Meters would almost certainly bleed over to TVs tuned to channel 2 (54-60 MHz.), and running FM would ensure that your neighbors would hear you and your identifying callsign loud and clear. Having no desire to earn the Worked All Neighbors TVI Award, one stayed away from Six Meters in places where there was that interference potential.

Since then, cable TV systems started becoming more prevalent, and people replaced their TV antennas with a 57+ channel feed from a service provider.  More recently, analog NTSC TV has been replaced with digital ATSC, and many of the stations on Channel 2 have switched to a UHF channel.  These three changes in American television have greatly reduced the interference potential on Six Meters.

Speaking of TV, back in the analog days, PRC-25s and 77s worked really well for hearing the audio on TV channels 2-4, and I suspect that if we ever get Five Meters back (Ireland already has it), those of us with VHF milsurp radios will be among the first to be QRV on the old/new band.  The old pre-World War II 5 Meter band was 56-60 MHz., which still remains within the frequency range of TV Channel 2 in the US.

After moving back East, and reconnecting with old friends who share similar interests, I find myself doing living history displays again, with FDR being my first event in a long time. Much like an SCR-300, the PRC-25 is one of those milestone radios that might be considered a “must-have” for a green radio collection. So when a fellow ham who is also a green radio enthusiast had a complete PRC-25 for sale, I took the opportunity to add one to my collection again, having swapped out my original PRC-25 many years ago.

The PRC-25 (and PRC-77) make a good first radio for the beginning green radio enthusiast. They are relatively inexpensive, their accessories are readily available, they are easy to power up, and are ready to go on Six Meters.  Technical information is downloadable right off the Internet, and if you are lucky a local old-skool Army/Navy store might have some of paper TMs in their inventory of military manuals.  All you really need to get one on the air is a power source that provides 12V and 3V DC, a handset, and a 6 Meter antenna.  That last item can be anything from a base antenna, to a telescoping whip used on HTs, to something you put together out of zip cord (the civilian equivalent of WD-1) from FM 24-18 or MCRP 8-10B.11.

Download manuals at
Practicals available at

The big question with milsurp VHF sets is whether or not they’ll be able to talk to other 6 FM ham rigs. The FM voice deviation of a PRC-25 is somewhere around 10 KHz. Modern 6 Meter ham gear is closer to 5 KHz., although I’ve seen some rigs that are pushing 7-8 KHz., usually older stuff.  If you yell into the handset mic of your PRC-25, someone listing with an FT-817, for example, would hear some clipping off the audio peaks. Likewise, someone running the standard <=5 KHz. deviation out of their civilian ham rig is going to sound a bit on the soft side when listening with your ’25. The other issue is the 150 Hz. “new” tone squelch, but you can turn it off on the PRC-25 if you’re trying to communicate with a civilian radio (or an older military radio that uses “old squelch” for that matter).

As a piece of amateur radio equipment, a PRC-25 gives you a QRP (~2 watts) FM transceiver on the 6 Meter Band. Six meters is the most fun VHF band to operate on (especially during band openings), and although the weak signal operators prefer SSB for DX voice work, anyone who listens to the VHF-Low band regularly knows that FM will also work when band conditions are right.  The radio is simplex only, and the 50 KHz. channel spacing renders it impossible to get on the 6m national simplex channel of 52.525 MHz. However, hams who are green radio enthusiasts will be found at hamfests, living history events, and vehicle rallies operating usually on 51.0 or 51.6 MHz.

In TM 11-5280-398-12, Uncle Sam specs out the range of the PRC-25 at five miles. I’m thinking that’s with the standard tape antenna.  Reports from other hams indicate that depending on the terrain, antenna used, and band conditions, you could get as much as 10 or more times that distance.



My PRC-25 is not “mint,”  but neither is it all beat up. It has character. I sometimes wonder where it served, and what stories it might tell. Did it spend some time in the Central Highlands of Vietnam? Did it help watch over the Fulda Gap?  Maybe it’s last tour of duty was in the commo section of a National Guard unit where it was only used one weekend a month, or maybe it ended its career as part of the inventory belonging to a post like Ft. Jackson, SC or Ft. Sill, OK where trainees used it while learning how to shoot, move, and communicate.  The stencils on the radio are very quiet in that regard. Regardless where it’s been and what it did, it’ll spend its retirement communicating with its brethren on 6 meters,  acting as a point of reminiscence for those who carried one in the service of their country, and honoring the past by helping teach an important part of American history.

A nice post from a fellow ham radio operator that I thought was worth sharing.

The Erie Lackawanna Railroad Logbook This is a train log that logged trains that traveled along the line that went from Chicago through New York State and Pennsylvania, then New Jersey, and which finally ended up in New York City. It defines my youth – in the 1960’s, the train tracks were pulled up in […]

via On Logging . . . . — The Free Range QRP DX-er

On Logging . . . . — The Free Range QRP DX-er