26 November 2017

Voice of Victory

Let's enjoy a great bit of history. As WWII opened the US Army realized it needed to modernize and upgrade its communications equipment, and do it ASAP. The Army Signal Corps turned to private industry for help. The US was lucky - by the late 1930s the country was a leader in civilian radio technology thanks to companies like RCA and Westinghouse. The US also led in the area of Amateur Radio technology; there was a lot of technology overlap between commercial and Amateur radio at the time and many major commercial equipment manufacturers also dabbled in amateur radio hardware.

One leading Amateur radio manufacturer, Hallicrafters, turned a Signal Corps requirement for a self-contained mobile radio system into one of the most successful communications systems of WWII - the SCR-299. The SCR-299 was a truck or shelter mounted radio system that contained every component needed to provide long range AM and CW communications. It became the backbone of tactical communications for US armed forces on battlefields across the globe.

In 1944 the Hallicrafters company hired the famous industrial training film company, Jam Handy (yes, Jam Handy) to produce a comprehensive half-hour story on the SCR-299. Hallicrafters was rightly proud of their accomplishment and wanted to showcase it.

This movie is a minor classic in the Amateur radio world, and a must-see for anyone that ever owned, or lusted after, a Hallicrafters radio.


W8BYH out

24 November 2017

So Does PRC-77.com Acutally Own A PRC-77?

I have been looking for a good working example of an AN/PRC-77 for over a year now, but for several reasons have been reluctant to pull the trigger on buying one. First is that nagging little inner voice that keeps asking me "why the heck do you need a 40 year old obsolete, overweight and under powered radio you can't talk to anybody with?"  My inner voice was making some good points, but I'm the master of impulse buying over self control. The hunt continued, but with some caution.

My first concern was not getting burned. There are plenty of PRC-77 radios available for sale on the internet. Some come from surplus vendors like Fair Radio Sales and Murphy's Surplus in the US or Army Radio Sales in the UK. At any given time there are as many as a dozen on offer on eBay. Many of these are coming out of Europe where the radio saw wide acceptance with our NATO allies. Then there are the radio-specific venues like amateur radio hamfests and militaria shows and events. But when you buy a radio you also have to buy the seller's promise that the radio actually works. Before buying a radio I wanted to personally inspect the unit and look the seller in the eye as he assures me it works.

But who would I talk to if I had one? Well, you actually can talk to fellow ham radio operators using the PRC-77 since part of its frequency coverage falls in to the Amateur Radio 6 meter band (50 - 54 mHz). Most of the HF radios sold today include 6 meters FM, including the incredibly versatile and portable Yaesu FT-817.

The Yaesu FT-817 (top) communicates with the PRC-77 on the
Amateur Radio 6-meter band (50 - 54 mHz)

A few weeks ago while attending the Stone Mountain Hamfest in Atlanta I stumbled on a guy in the boneyard area selling a small collection of military radios, one of which was a PRC-77. The radio looked a little rough but the seller assured me it worked fine. He had no way of proving the radio worked since he didn't have a battery pack or accessories, but as I looked over his offerings it struck me that I'd seen this fellow at hamfests in the Atlanta area before. He was a regular and if I had a beef with the radio it was likely I would run in to him again at another local show. His asking price was right, and he even came down a bit after I grumbled about having to take his word that the radio worked. When all was said and done I walked away with an early RCA production model PRC-77 that I hoped would work as advertised.

She may be ugly, but she's mine

Standard accessories are another issue, but the good news is that you can buy complete sets of PRC-77 accessories - handsets, whip antennas, tape antennas, carriers, etc. at very reasonable prices from several sources. Within an hour of getting this radio home I had an antenna and handset on their way through the magic of eBay.

But what about juice? Like so many US military radios of its time the PRC-77 used a non-standard battery. The magnesium 'slab' battery, the BA-4386/U was introduced for the PRC-25 and was first issued during Vietnam. designed to work with both the PRC-25 and the PRC-77. In the 1980s the US military replaced the magnesium battery with a smaller, lighter lithium battery (you could carry two in the PRC-77's battery case, one powering the radio and one a spare). You can still buy both batteries - dead magnesium batteries are used by reenactors for display purposes, and the lithium batteries are still manufactured but run over $100 each. I needed something cheaper and easy to replace. Luckily there are two battery replacement options that take standard D-cells. One is a battery 'bracket' manufactured by Brooke Clark at prc68.com. The other is a D-cell battery case manufactured by the (now defunct) German firm Telemit. The Telemit cases are long out of production but can be found on the surplus market.

Top left: prc68.com battery 'bracket' (10 D-cells)
Top right: Telemit (Germany) clamshell battery pack (10 D-cells)
Bottom: original BA-4386/U magnesium battery

I still needed to find out if this little beast worked. After some inquiries, a friend of a friend of a friend arranged for me to take the radio to a super secret test facility hidden away down a dark alley in the Atlanta area. I'm happy to report that the radio passed all of its operational tests with flying colors. Now, the term 'flying colors' is relative. This is an early 1960's design, built using 1960's components. It is very broad banded by today's standards (50 kHz channel spacing) and the specific test equipment used by military repair and calibration shops was hauled to the landfill years ago. All we could do was test the radio using a generic (but very precise) spectrum analyzer. But pass it did! Frankly it performed better than I thought it would given the radio's external condition.

It's Alive!

In short order the accessories arrived and the radio went out to play. During a recent ham radio gathering at a local park I brought my PRC-77 along to play with some friends and run a small 'Cold War net'. Tons of fun! I even brought along a few Czech RF-10's so we could run an 'Iron Curtain net'; two models of radios that actually did face off against each other within eyeball distance across the West German/Czechoslovakian border. The strains of 'Neunundneunzig Lufballoon' were filling the air!

"Comrade imperialist, can you hear me?"
"Roger you godless commie, I read you lima-charlie. 
I'll trade you a pair of blue jeans for a case of Pilsner!"

So, one and done? Ha, hardly! As so often happens when you go after a goal with determination other opportunities appear. Not long after my hamfest discovery an auction popped up on eBay that proved too tempting - a working PRC-77 along with a literal pile of accessories - multiple antenna sets, handsets, a PRC68.com battery bracket, a USGI backpack radio carrier, manuals and more. After some back-and-forth bargaining a deal was struck and a second PRC-77 was added to the group.

"He who dies with the most toys wins"

So let's get back to the original question posed in the opening paragraph,"why the heck do you need a 40 year old obsolete, overweight and under powered radio...?" The answer is simple - I don't need any of this communications gear. However, putting it to use helps celebrate the history of US military communications technology during the Cold War era and puts in context the communications technologies that are ubiquitous today. Less than 30 years ago, before smartphones and the internet, your fathers and grandfathers were using this technology to defend America. It's important to remember what was accomplished - what was doable - with simpler technologies.

W8BYH out

06 November 2017

Can You Hear Me, Comrade?

A Fine Blade: Slyšíš mě, soudruhu?: That's Czech for, 'can you hear me, comrade?'

Several weeks ago I wrote a post on my A Fine Blade blog about my experiences with the Czech RF-10 manpack radios. Since the topic fits well in this blog I decided to do a cross-post.


05 November 2017

Where It Began

I've been writing about radios on and off on my other blogs for a few years, mostly in relation to other topics under discussion like disaster response or preparedness. But since I've recently renewed my interest in ham radio and found myself writing more and more about it on social media I figured it was time to stand up a blog devoted to communications where I could indulge in longer, more focused discussions.

So why 'PRC-77', or more accurately, AN/PRC-77? I grew up in the Army, joining right after graduating college in 1979 and retiring over 20 years later in 2002. I wasn't in the Signal Corps, I was in the Engineers. For me and the Soldiers in the units I served in radios were just a tool. A critical tool to be sure, but they were the means to an end - effective command and control. From that perspective I was always impressed that our radio systems just worked. Pick up a microphone, mash the push-to-talk button and throw out a callsign. The people or units I needed to talk to almost always came right back. I didn't think about the magic or effort behind making this all work. It just worked. Of course I understood that there was always a layer of Signal Corps support standing behind all this magic, from our company-level signal section to national-level satellite-based digital C3 systems, but there was no need (and often no time) to marvel. Just as the Engineers had the task of building roads, bridges and airfields the Signal Corps had the task of making sure guys like me could talk to who they needed to, when they needed to. We all had our jobs to do, and the Signal Corps guys and gals did theirs superbly.

Since most of my time was served in separate company, battalion or brigade level units we relied a lot on smaller portable radios for team level communications. Right up through Desert Storm, and beyond, this meant the ubiquitous AN/PRC-77. The radio was designed by RCA in the late 1960's as an all solid-state update to the AN/PRC-25 and was quickly adopted and shipped in staggering numbers to Vietnam. It was the right radio at the right time; rugged, waterproof, reliable as a brick and highly configurable. It was just the radio we needed to make the new tactic of vertical envelopment by helicopter work. As much as the M-16 rifle and the UH-1 helicopter, the 'prick-77' provided a visual benchmark for the war in Vietnam. Look at any wide angle picture of ground operations in Vietnam taken from 1968-on and you'll see at least one PRC-77 in the shot, usually strapped to a Soldier's back.

AN/PRC-77 being used during an airbmobile operation in Vietnam

By the early 1980's the PRC-77 design was showing its age and the Army desperately wanted to upgrade their tactical communications suite. But money was tight and more critical systems like the new M-1 Abrams tank and the Bradley Fighting Vehicle were getting all the funding. The PRC-77 soldiered on far longer than it should have, but its length of service was a testimony to its excellent original design and overall ruggedness.

And that's how I came to appreciate the AN/PRC-77. It was the radio I turned to time and again to accomplish the mission. Whether you were directing a convoy, running a rifle range, setting up a drop zone, conducting a recon or chasing bad guys around the desert, it got the job done. By today's standards the PRC-77 is obsolete; it's all analog, it's heavy, it puts out a weak signal, it isn't narrow band, it eats up batteries and it doesn't offer the communications flexibility needed on the modern battlefield. But like a '65 Mustang that is underpowered, doesn't handle well, has no trunk space and is uncomfortable on long trips, the PRC-77 is easy to love. In its time the PRC-77 was the best tactical manpack radio available and there's still a lot to admire about its ruggedness, simplicity and reliability. It just worked.

So while this blog will focus on ham radio and general communications topics, it is also take an occasional look back at the radio gear that defined an era in military communications.