The discovery of the cat was so surprising Paul stepped back a moment to collect his wits. Then he reached out and touched the animal, just to confirm it was real and not his imagination. The cat stood, stretched, and rubbed up against his hand. This was real and it was Hector. His first thought was the cat had somehow gotten in the duffel bag and made the journey to the cottage like a stowaway. But that couldn't be right, how would he have escaped the bag then zipped it closed again?
This made little sense and there was definitely something fishy going on here though he couldn't imagine what it might be. He gathered up Hector in his arms and carried him into the cottage where he opened a can of cat food and fed the critter on the assumption he would be hungry. He glanced at the clock. It was after midnight now, too late to call Stella he thought. He would call her at first light to let her know that the cat was okay and with him. Of course she would ask how this was possible, and he had no idea how he would respond.
Once his blood pressure had retreated a bit and he was thinking clearly again, he knew. This was a standard tradecraft play intended to get his attention and it worked. He knew immediately what action it was intended to provoke. Paul had been out of the "business" long enough he was certain this had nothing to do with him. It was about his nephew, Mac Hodges.
Mac told him not more than a month ago he was working on something important and would be going off-grid for awhile. Apparently, that was working so well he couldn't be found. Whoever was looking for him probably assumed Paul could make contact with him and apprise him of this event and perhaps in the process, expose his whereabouts.
His first thought was that he wouldn't give "them" the satisfaction. But as he thought more about it he decided to contact Mac. It would be useful for his nephew to know someone was looking for him, and the two had a longstanding pact that there would never be secrets. Especially about the "business".
With Mac being off the grid he couldn't be called. Or tracked. At least not in the traditional sense which is why Paul walked into his ham radio room and fired up the gear. A glance at the clock on the wall told him it was 3am now and he decided the 40 meter band would work just fine. With the solid-state amplifier set to 1,000 watts he touched his Morse code key sending "QRL?" first to see if the frequency was occupied. It wasn't. He then began calling CQ using his call sign with a /QRP tagged onto the back of it. QRP indicates low-power is being used even though in this case, it wasn't. He made six calls like that then stopped. Several stations responded to his call but he ignored those as he shut the station back down.
The message had been sent.
Ham radio technologists have built an entire network of receivers that endlessly scan the HF bands decoding the Morse code signals each receives, skimming call signs, signal reports and frequencies along with other pertinent data. This info is pumped into a central database that collates it and serves it up on the web in real enough time.
The system includes dozens of receivers, hundreds in fact, located all around the world. Since these reception reports are overlayed on maps, the data provides HF operators a visual representation of current shortwave band conditions. It's become typical for a ham to send a CQ then consult the online map to see the diverse places where his signal is being "heard". This knowledge, along with the signal strength report and location of each receiver on the network provides the operator with knowledge useful for improving his station efficiency, especially that of his antenna system.
More importantly, system APIs make this same data available to 3rd party developers whose software creations can make the data even more useful. One application can be configured to look for a specific call sign and send an alert whenever it is seen. Amateur radio enthusiasts incessantly hunt for desired stations, often in faraway or rare locations. Without this kind of assist, this can be a Herculean manual task given the wide swath of radio spectrum allocated to the service. A person could tune a receiver all day and night and still miss that desired station.
This alerting system can be configured such that when one specific station call sign is received anywhere in the world, the report from that reception can trigger a text message or email alert letting an operator know that the desired station has been spotted along with the frequency and time when it was received.
Paul and Mac made use of this system for their own private messaging. The system manages call signs uniquely. So W1ABC and W1ABC/1 or W1ABC/MM indicates the station is operating from a ship (maritime mobile) are handled as different stations with the alerts handled separately. Mac had setup an entire playbook of messages. For instance, if his Uncle sent his call sign with a /2 on the back of it, that meant one thing while a /3 meant something else. This provided them with a terse, yet effective means to exchange pertinent information. What Paul sent with the /QRP call was their "Bat Signal" or DEFCON 1. It was an urgent call to make contact as quickly as possible.
As intended, the reporting system received that signal and reported it to the entire world. In Walnut Creek, California a Linux box running a little custom software noted the callsign plus the /QRP triggering a message that was sent via telnet to the WinLink amateur radio system that can queue messages, like any email server, and make them available via a radio link. Next time Mac logs into one of hundreds of WinLink stations using his HF radio, he will be presented with the message from his Uncle.
It wasn't as fast as email, but it was off the grid with a step level of increased complexity for anyone attempting to track his location. And if someone did manage to crack this somewhat arcane method, the only data they would collect would be a ham radio call sign with a /QRP at the end of it. If they dug deeper they might discover the server in California, but that couldn't be traced directly to Mac's location. His retrieval of that message would be completely obscured by use of an HF radio link to collect it. With good radio propagation Mac might have access to a WinLink station thousands of miles distant from his actual location.
The two of them, with long experience in government espionage, deemed this method good enough for hand grenades and had been using it without incident for several years. Having worked for Uncle Sam, they both knew the many ways people can be found in this era. From traffic cams, ATM cams, retail store cams, credit card use tracking, cell phones, internet connections and automobile GPS, it's downright impossible to be invisible in the good old USA.
Unable to sleep, Paul gathered up the cat, along with a few other things, and headed for home. The dark skies of 5am didn't make the drive any easier, but at least he was wide awake without the need for coffee.
In a high-tech bivvy bag somewhere in South Dakota, Mac Hodges stirred himself awake. No matter how much he longed to sleep-in some mornings, his internal alarm always sounded at 5am.
Today was the normal morning routine including firing up his Jetboil to make coffee. With a little more time to kill this morning than most, he stuck his telescoping vertical into the ground and extended it the full 17 feet. He was far off the beaten path and hadn't observed any campers or hikers in days. His tiny, battery-powered HF transceiver came to life and the signals in his earbuds were clear and strong. The good band conditions convinced him now might be a good time to check his WinLink mail. Connecting the radio to a tiny Raspberry Pi running Ubuntu and paired with a small five-inch display and keyboard was all the computer power he needed, or could carry.
Minutes later he connected to a server in Texas on 40 meters and retrieved his mail. Ten minutes after that, his campsite was scrubbed clean and he was hiking back down the mountain to his waiting Scout Harvester.
Paul never did call Stella. When he walked in the front door of their home at 9am that morning, carrying Hector, she knew something was up that would be difficult to explain.