Long Range Communications

[Gelrir]

I suspect there are three different things being discussed here: the super-low frequency equipment used to activate teams from Prime Base; the tactical radios of the Project (symbolized by the PRC-70); and whatever transcontinental system the Project expected to set up after the Atomic War.

The Military Affiliate Radio System communicated fairly reliably from Vietnam to North American in the 1960s, with equipment that would fit in the bed of a deuce-and-a-half. I think you could justify a V150 dedicated to being a comm vehicle, with an extensible mast (similar to the ones used by television remote vans); or the same comm capability built into a MARS-One or Scientific-One vehicle. Some images and info:

http://www.fold3.com/image/244368538/

http://www.ne7x.com/web_pages/mobile1968.htm

http://www.qsl.net/ea4bb/EA4BB/Collins_KWM-2A.html

http://www.w2xc.com/KWM-2.htm

http://www.collinsradio.org/cca-collins-historical-archives/the-equipment-of-collins-radio/the-grey-boxes/kwm-22a-transceiver/

http://www.wb4hfn.com/COLLINS/Documents/Brochures/KWM2/Brochure-KWM2.htm

http://www.radioing.com/collins/tr01.html

The 4000 kilometer range quoted for the PRC-70 is for sending and receiving CW (morse) or FSK (modem, more or less) with a doublet antenna (i.e., not just the usual whip on Project vehicles). While the doublet antenna is normally stretched out parallel to the ground, I'm sure a well-designed vertical pole could do something similar. Between two PRC-70s, with the right conditions, time of day and operators, ranges are more like this:

• doublet antenna, Morse code or modem: up to 4000 km
• doublet antenna, voice: up to 800 km
• whip antenna, FM voice or SSB voice: up to 40 km
• whip antenna, AM or FM voice: up to 24 km

(this information is converted from "Operator's Manual, Radio Set AN/PRC-70", page 1-10).

I imagine the super-low-frequency system can't be picked up by the tactical radios, so the details may not be too important to game play.

--
Michael B.

[RandyT0001]

If you visit:

http://en.wikipedia.org/wiki/Radio-wave_propagation

you can see the radio spectrum broken down into bands. The VLF and LF bands are low frequency and travel by ground waves, following the curvature of the Earth. The are used to send short messages to ships and submarines at sea. (Flash traffic in the movie "Crimson Tide".) Used by MP to wake teams. The radio equipment the teams have can not send signals at the proper frequency to respond with a message back to PB.

The PRC-70 operates across the HF band and about 40MHz into the VHF band. The PRC-70 has a range of 2500 miles if it is properly set up to operate in the CW mode, in the lower end of the HF band, with the proper antenna, the doublet, erected at a sufficient height. It does this by skywave.

http://en.wikipedia.org/wiki/Skywave

HF can also use relay stations to increase the range of signals.

The VHF band on the PRC-70 is for local communication with units close to the radio. From a few miles up to tens of miles depending upon how high the antenna is and ground clutter. This is a direct line of propagation communication mode. A relay or repeater station can be erected on a tall tower, hill top, etc. that recieves and re-transmits the signal at a higher power level. The combination of height (few hundred feet) and increased power expands the signals coverage area to fifty or sixy miles in diameter. Relays can be simplex, one frequency for both recieving and re-transmitting, or duplex, a frequency for recieving and another about 500kz from the other for re-transmission.

The doublet antenna is a half wave dipole. It is made of two wires set in a single line, one wire is connected to the radio and the other is connected to the ground. A horizontal orientied dipole radio radiation pattern is like a doughnut (with a very tiny hole) and the wire goes through the center of the doughnut hole. If you set the wire of the antenna on a north-south axis most of the energy is transmitted to the east and west. A vertical whip antenna is a quarter wave antenna (half of a dipole). The ground of the Earth forms the other half of the "dipole" of a vertical antenna. They radiate in a 360 degrees around the vertical antenna but at reduced power from a dipole.

A type of directional antenna is referred to as the Yagi-Uda. To learn more about it read this article:

http://en.wikipedia.org/wiki/Yagi-Uda_antenna

Whereas the horizontal dipole has a radiation pattern like a doughnut, the Uda-Yagi has one side of the "doughnut" at a smaller, less powerful size while the other side is bigger, more powerful and shaped like ovaloid or egg. They are often the easiest directional antenna to make and are use for radio direction finding.

[kato13]

Good information. Thanks.

Other than an overlap in Acronyms the
Military Auxiliary Radio System (MARS) seems like it would be something the project would look into supporting financially. Maybe sponsoring contests or something so they could start to make connections to users whom if they survived would be valuable postwar.

[Gelrir]

Having pondered it some more, for my campaign (a 'classic' period setting) I'll probably go with this:

In the wake of World War III, landlines would be cut, microwave links destroyed by EMP, and many satellites shot down or left to spiral down into the atmosphere. The Project wasn't nearly about to launch its own set of communications satellites covertly (one way to inadvertently cause World War III, at least!). There was some uncertainty about the effectiveness of long-distance radio transmission in the wake of a nuclear war, but in the end the Project decided to stick with radio transmission.

Team activation signals, and low-rate strategic messaging, are sent on VLF frequencies. Transmitting antennae for this system are very large -- kilometers across for a trans-continental system -- and transmission is very inefficient; power requirements are in the hundreds of kilowatts, or even several megawatts. However, receiving antenna are simple coils, as small as 10 cm in diameter; and the receiving radios in boltholes are an unimpressive piece of rack-mounted equipment (including decryption equipment).

The actual coil antenna used for Project boltholes is about 30 centimeters in diameter, wound with more than a thousand loops of insulated wire (so: more than a kilometer of wire). Note that the antenna design doesn't tell you much about the frequencies being received, except that it's VLF. It's placed just at the surface for most boltholes, mounted on a sturdy pillar anchored in the bolthole structure. An artificial rock of thick, fiber-reinforced polyimide resin is also mounted on the pillar, and encases the antenna; it's very strong, chemically resistant, and fireproof up to at least 800o F (1300o F for brief periods). The artificial rock also means the team probably won't be able to get at the antenna wire.

The transmission rate, using FSK modulation, is about 5 characters per second (using ASCII 8-bit characters). Encryption padding and other "non-text" parts of messages roughly double the transmitted wakeup signal. A wakeup signal might be 300 characters of useful information -- 600 characters as transmitted in encrypted format: thus 2 minutes to transmit.

A game-play/dramatic advantage for this: the transmitters are huge and need a lot of power; but receivers can be trivially small. So the typical player-character Recon team can receive their instructions, but can't chitter-chatter back and forth with Damocles or whomever.

The 300 character size for the wakeup signal is based on the one at page 7 of Operation Lucifer.

--
Michael B.

[stormlion1]

We once played a game where we needed to enter Philadelphia and scout out and repair if possible a transmitter antenna and a repeater atop on of the surviving skyscrapers. Actually a interesting game as not only did we have to get into the city, which bore a striking resemblance to "Escape From New York" and "Cloverfield" in parts but had to ascend to the top of a surviving skyscraper. Actually pretty fun except for when we wrote out our equipment lists for the ascent no one wrote down the tools and parts we were going to need.

[Project_Sardonicus]

www.morrowproject.com

When I first read about the Morrow Project the communications system seemed fine.
But now well doesn't it seem a little primitive, this organisation with all it's amazing super technology keeping in touch via morse code and long range radio chat.

So what I was considering was the project had an early version of the world wide web. Not so much team members getting proto ipads, but rather an ambitious scheme to lay fibre optic cable across the nation. Each time a deep drainage or electrical cable was laid the project gets to add some extra cabling.

Then various, not all bolt holes get a computer station to communicate with prime base. I'm thinking very much 70s, 80s tec green flickering screen solid units. And like the early telex systems that linked NATO bunkers these systems can be redirected to go around disabled hubs. The idea being the recon team members spent a couple of weeks recording data and making observations. Then goto their hub and upload the data to prime base.

With the project having small human resources, much of this would be filling in standardised forms which are then processed by alogrythms.

In addition there's a supplementary radio system that can send even smaller amounts of data, but is very much a predecessor of the 3/4g world we live in.
An interesting system being that this would allow prime base or rather the central computer that is running these algorythms to update the nav comp.

So if the team is doing well or has a need it may gift them locations of new bolt holes, perhaps containing exciting new gear. If however their reports are slack, or erratic or in other ways they seem to have gone rogue. Then they may find the nav comp wiped, their fusion bottle shutdown and if their behaviour indicates they've been wiped out gone over to the dark side or what ever. Then perhaps the fusion bottle it's self is detonated, the assumption being such valuable treasure would be kept at the very heart of the enemies citadel.

Certainly if one is looking to prevent teams going gun happy, then having to lug around kilos of camera equipment, laptops and other gear to do their weekly reports may reduce capacity for bullets. A

[mikeo80]

We once played a game where we needed to enter Philadelphia and scout out and repair if possible a transmitter antenna and a repeater atop on of the surviving skyscrapers. Actually a interesting game as not only did we have to get into the city, which bore a striking resemblance to "Escape From New York" and "Cloverfield" in parts but had to ascend to the top of a surviving skyscraper. Actually pretty fun except for when we wrote out our equipment lists for the ascent no one wrote down the tools and parts we were going to need.

I am from Philadelphia. It would be hard to find ANYTHING left. IF you go with V3 rules, Philly got a 25 MT SS-18, and a SS-N-17. Depending on exact hit points, maybe something left...Somewhere. I will look at V4 later to see what the new version says Philly got.

According to the Travel Guide out of the Supply Bunker Website, Philly had a little left down by the Airport. By definition, not many high rises near airport.

http://www.thesupplybunker.net/Travel_Guide/states/pennsylvania.html

My $0.02

Mike

[stormlion1]

Man its been a while since we played that game, I think the building was described as "leaning, and not a single intact window left above the third floor" and lots of fire damage. Actually a lot of buildings were described as still standing, but plenty were described as leaning against each other for support and melted glass being piled waist high in the streets in spots around there bases. I just remember leaving the vehicle west of Boathouse row and hiking in with the gear. Just for fun, City Hall did survive and was practically a fortress of a cannibal tribe.

Main thing had been to bring a surviving antenna online so it could act as a repeater along the East Coast. Morse Code was used heavily as a medium as it was harder for groups without knowledge of it to decode. But the main thing was to bring surviving communications infrastructure online to supplement the Projects own communication infrastructure that we had to put up ourselves.

[robj3]

Communications concepts:
1. Meteor burst radio/data - using ionisation tracks caused by meteors as they burn up in the upper atmosphere.

Several thousand kilometre range as previously discussed here:

http://forum.juhlin.com/showthread.phpt=2688

2. EME (Earth-Moon-Earth) communication
Using the Moon as a reflector - eliminates need for satellites, global range when the Moon is in the sky at each location.

wiki entry is a good start:

http://en.wikipedia.org/wiki/Earth-Moon-Earth_communication

pdf from Princeton is excellent but potentially too detailed:

http://physics.princeton.edu/pulsar/K1JT/EME_2010_Hbk.pdf

Summary is that 1-2m diameter satellite dishes are usable, or ~12-15 foot yagi antennas.

Data rates wouldn't be too bad with modern digital comms (think dial-up, not broadband or LTE type speeds).

You could use inflatable satellite dishes, as manufactured by GATR:

https://www.GATR.com

30kg kit runs on compressed air to make a 1.2m diameter satellite 'dish'.

I don't like ELF because of the geological, power and size restrictions on transmitter siting. The receiver antennae would need to be pretty large for the boltholes to get messages.

[Gelrir]

Actually, SLF receivers can be very small.

http://en.wikipedia.org/wiki/Super_low_frequency

Yup, transmitter requires 10s of kilometers of "power line on poles"; the Project has hidden bigger things. The Project has large amounts of electrical power.

I think the biggest issue with an SLF or ELF system: the chance of being mistaken by the Soviet Union for some sort of secret backup to the Navy's communications systems. "Look, Comrade-General, the Americans think we won't notice their secret strategic transmitter system."

Any system requiring above-ground antennae or dishes isn't good for communication with boltholes.

There are a lot of systems to use once you've waked the team up. The basic PRC-70 radio isn't really a "pick up the handset and talk to any other PRC-70 in North America", but for Morse code and low-rate modem transmission it's not too bad.

--
Michael B.

[robj3]

Michael B. wrote:

Actually, SLF receivers can be very small.

Sure - but I wasn't talking about vaguely efficient antennae that sit above ground level.

Any system requiring above-ground antennae or dishes isn't good for communication with boltholes.

Not necessarily; antennae can be disguised. The problem is with redundancy. Weather, earthquakes, nearby nuke detonations, fires, etc. could damage above ground equipment.

Large antennae aren't required. The SNOTEL network in the Western U.S. is a good example of an operating meteor-burst comms system.

I don't like Project satellites or ELF comms capability for lots of reasons and I agree with this:

I think the biggest issue with an SLF or ELF system: the chance of being mistaken by the Soviet Union for some sort of secret backup to the Navy's communications systems.

[Gelrir]

An ELF system for initial team wakeup-and-orders has a couple of useful gaming features:

• the team knows they probably can't turn on their radio and call back
• direction finding for ELF signals is not trivial, so Prime Base (or at least the antenna array) won't be found easily after the Atomic War. And even if you do direction-finding, you 'just' find the area with the big rocks underground, heh.

The entire antenna system can be buried underground; the Navy was gonna do that, but it was too expensive. I wonder if a North-America-only system might be more suitable for an underground antenna An organization with powerful cutting lasers might find making an underground antenna a bit easier.

A useful description of the Navy's first ELF system:

http://www.google.com/urlsa=t&rct=j&q=&esrc=s&source=web&cd=3&cad=rja&ved=0CDEQFjAC&url=http%3A%2F%2Fwww.oldradio.com%2Farchives%2Fjurassic%2FELF.doc&ei=Dd3vUtKQG8KHoQSc84CYAw&usg=AFQjCNERLsEw4w0Y4D4vIY-t9gultB9YJg&bvm=bv.60444564,d.cGU

Note the coverage areas in the first big "Seafarer" map, and the labels: Michigan (where the ELF system was eventually built), New Mexico, and Nevada (where PB is located).

Info on ELF direction finding:

http://www.vlf.it/minimal2/minimal2.html

A limitation for the Morrow Project: they probably wouldn't ever want to transmit on their big ELF antenna before the Atomic War. Also, the antenna needs to be placed at a location with a wide (kilometers long) ancient granite.

Hmm, from a Geological Society bulletin: " ... The Precambrian complex of the Gold Butte-Bonelli Peak area [in Nevada] is about 25 by 35 km and consists of gray porphyritic perthite-quartz-biotite granites and quartz monzonites (adamellites) that intrude Precambrian garnet-cordierite-sillimanite and hornblende gneisses, migmatites, and older granites, pyroxenites, and hornblendites. These younger granites strikingly resemble the Finnish rapakivi granites geologically, petrographically, and chemically. They are exposed over an area approximately 20 by 30 km and represent the roof of a batholith with numerous stocks, dikes, roof pendants, inclusions, and plutonic breccias."

More info on Gold Butte:

http://mrdata.usgs.gov/geology/state/sgmc-unit.phpunit=NVYgr%3B0

http://angeles.sierraclub.org/dps/archives/dps00514.htm

Gold Butte is a ghost town on the Nevada/Arizona border.

http://en.wikipedia.org/wiki/Gold_Butte,_Nevada

The mesa has very old granite, the basic requirement for an ELF transmitter. According to page 12 of this book:

http://books.google.com/booksid=QJkwT30_P6cC&pg=PA9&lpg=PA9&dq=precambrian+granite+in+nevada&source=bl&ots=Ym75TwlD2b&sig=xuXn5uYHAX4gi4L18PprjjlVcd4&hl=en&sa=X&ei=d-PvUuLVFo7boATVmoDQDQ&ved=0CFsQ6AEwBw#v=onepage&q=precambrian%20granite%20in%20nevada&f=false

... that's about the only Precambrian granite in Nevada, so quite likely the Navy's (not-taken) choice.

--
Michael B.

[Gelrir]

I do like the meteor-trail system, but in the end I have to say for "regular ol' comms between teams" the PRC-70 does pretty well. Set up a wire, wait till sundown, and send Morse or modem traffic over most of North America.

One problem with Morronet: if someone (say the government) DOES get interested, they (a) cut the wire, and (b) follow the wires to all your locations. With a project taking at least two decades to set up, that seems a bit risky. And if the answer to that is "well, the government secretly likes and assists the Project", then the Project should just piggyback on government systems.

--
Michael B.

[kato13]

Tundra Orbits

Once Again I am redesigning my project from scratch. Communications are of course a priority.

I came across this when working on my planning

http://en.wikipedia.org/wiki/Tundra_orbit

It seems to me that if the project could put satellites in this orbit before the war (the company using planning to use them goes out of business ) or if it chose to launch a cluster of 3 after the war they could be pretty useful for communications.

You would need tracking software to transmit to it, but as it seems to be a very unusual path for satellites so it probably would be out of the way from a majority of debris that use of any ASAT weapons would cause.

If launched before the war they would need a strong power source (fusion) and serious EMP shielding, but they could lay dormant until the project needs them.

If launched after the war, serious resources would be needed as you would need to put 3 units into a pretty high orbit. One could work but there would be gaps in communication.

Thoughts

[ArmySGT.]

Regarding the Tundra orbits.........

I like it. The orbits do stay over one portion of the globe much like a geostationary orbit. How far up though I don't think any in low orbits are going to survive the ASAT missions or resulting junk......

Maybe they are waiting in silos for a Recon Team to awaken the specialists that were meant to launch them when the Project came online

Makes for a great scenario!