Deployable Communications Concerns

Take this photo here:spinb

…and compare it with this one:


Removing Afghanistan from the matrix, let’s start to narrow it down. In the top photo, a team is setting up shop, out of pickup trucks, to operate in an area for a while. In the bottom photo, a team is setting up shop, out of pickup trucks, to operate in an area for a while. A lot more of these situations will be happening before its over- things are in the slow roll phase, as most folks who study conflict would agree upon. Get it?

Notice that giant whip antenna on the Afghan truck? That’s a low band VHF antenna that performs quite well in the terrain there.

First things first

Units cannot operate for long without sufficient signal assets- commit this to memory. It’s great to have the will to fight but without more thought than showing up with a rifle and a smile is going to carry you as far as the Bundys got. I know it sounds harsh but it’s true; the goal is to win folks. Losing sucks.

It was pointed out in recent discussion that the folks occupying Malheur had little more than cell phones initially…which means they were relying upon someone else’s infrastructure, easily compromised, and ineffective. I understand they were using radios secured on-site; on frequencies already well known to the authorities there.

There’s a serious flaw in using OPFOR’s equipment as your own when it comes to radio.

Rolling Your Own Plan

As many have pointed out before, tactical communications are tiered- local/unit level and regional/larger unit level.

At the local level, which is normally line of sight, communications should be implemented in certain ways, normally related to key Leader positions on the ground, and limited to transmitting only when really necessary. Those needs are covered here and here.

Our best options at the tactical level for regional communications are HF, and specifically NVIS for that magical 300-400mi radius, cutting out skip zones commonly found with HF propagation, which I’ve covered here.

On DF, Jamming, et. al.

While both of these are a definite concern, careful consideration should be given to both to make ourselves the most effective we can be. Complete jamming of all the HF bands is extremely hard to do, possibly next to impossible. The only thing that does that is the Sun; and even then, it’s not constant. Line of Sight(LOS) definitely can be, as any Iraq vet can tell you, but only in a very limited radius. As for HF, there’s plenty of ways that your transmissions can be interfered with, as five minutes of listening to 14.313mhz would demonstrate, but in keeping your transmissions short, and limited to pre-planned commo windows and report formats, the interference threat is greatly reduced.

Direction Finding is a concern, but there’s ways to mitigate this. As I pointed out here, there’s ways to mitigate this. The biggest one is through the use of directional communications. We do this by building directional antennas. A really simple one, known as the Sloping Vee, is seen here:


Hams know these as Vee Beams…as in, “they beam the signal in a direction.” Normally these are built from wire in the field, but there’s other options out there. It’s simply a dipole folded forward in the direction your transmission is meant to go; meaning keep a compass in your pocket, and know how to read a map to shoot an azimuth.

Deploying from a pickup truck rapidly and possibly on the move, stringing wire up in a tree may not always be the best option. You might want to include a large camera tripod as a simple and easy mast, or possibly a milsurp mast system.

A home built Sloping Vee configured for NVIS applications, using both a camera tripod and dual mobile Hamsticks, mounted on a plate of steel.
This system, from a reader, is a military mast connected to the hitch. It’s quickly deployable and very effective.

As I stated before, it’s really tough to completely jam an HF band. In addition, keeping solid, directional HF communications with another position could do a lot to further the mission…such as uploading pictures and real time data over digital modes after a good amount of practice. We’ve learned so far, to no one’s surprise, that the media is only there to reinforce OPFOR’s narrative. Working on networks you have complete control over is a big step in the right direction.

You can either hope for a miracle or start making one on your own. There’s going to be a lot more of these types of situations, and likely the response will be hasty in nature. Planning for it, and using our equipment gathered in a less than conventional way is going to make all the difference. It is an unconventional fight, act accordingly.

12 thoughts on “Deployable Communications Concerns

  1. mtnforge

    In your experience NCScout, what do you find as the most practical range frequencies to run on field expedient NVIS antenna’s to cover the skip zones?
    I’m looking at the map you posted:

    I’m not confident being new at this, if I am interpreting the specifically indicated Mhz on the map correctly in regards to what you wrote above:
    “…Our best options at the tactical level for regional communications are HF, and specifically NVIS for that magical 300-400mi radius, cutting out skip zones commonly found with HF propagation, which I’ve covered here.”

    I’m really fascinated by the whole concept of NVIS, it is so intriguing, its history of discovery, and really hope to understand its use fully to great advantage.

    1. mtnforge

      Does NVIS have its own particular skip zone? Or is enough energy projected straight up it produces enough of a signal to cover the area directly local to the dipoles location?

      1. Keypounder

        Think of NVIS operation as being similar to a large floodlight pointing straight up and being reflected by clouds above back down to the ground. With radio waves, the F layer of the ionosphere is the reflector, if and only if the ionosphere is ionized enough to reflect the frequency you are using. Reflection from the ionosphere is a function of solar activity, frequency, and the incident angle of the radio wave. The map above is a graphic showing what frequencies can be used to communicate with a particular location on a specific day given that day’s space weather and ionospheric conditions.

        With regard to NVIS, if the ionosphere will reflect the frequency you want to operate on, it will cover everything from immediately adjacent to 300 or more miles away. This is a particular advantage in rugged terrain, as there are no dead zones. Note that vertically polarized antennas typically do not receive NVIS well, as they have an overhead null; that is why horizontally polarized antennas are used.

        As height of an NVIS antenna increases, gain goes up (less power is absorbed by the ground) and as the antenna height gets above 3/8 of a wavelength, the overhead spherical pattern seen with a low antenna changes to a more directional double lobed pattern, which gets more pronounced the higher you go (up to a point, anyway.)

        The foregoing is a very basic explanation of the atmospheric physics inherent in NVIS operation; there is much more to be said about this subject.

  2. The map shown is actually depicting what the maximum usable frequency is for a particular area. I included it to demonstrate the sphere you’re likely to be able to communicate in wiht such a setup.

    NVIS works very well for frequencies at or below the 40M band. The properties of those frequencies as they radiate allow them to reflect better off of the layers in the atmosphere.

    Near Vertical Incident Skywave seeks to eliminate ‘skip zones’…areas in between you and your indended receiver where your signal will not be heard. The signal will eventually “skip”…but normally after several hundred miles, depending on the radiated power.

    For a standard dipole, think of it’s pattern as a sphere, with a 300-400 mile radius, sometimes less, sometimes more. When we fold that dipole, such as the Sloping Vee model, we now make a cone shaped radiation pattern in a particular direction, the same as we would with a Yagi antenna.

    There’s only one way to test the theories behind it and get good at it…and that’s to get on the air and do it.

  3. mtnforge

    Excellent, that really explained a lot I needed to understand, helped me tie it all together.
    Thank you very much.

  4. Pingback: Brushbeater: Deployable Communications Concerns | Western Rifle Shooters Association

  5. Quietus

    You talk milsurp field constructs: I use an AS-1743 multi-band dipole in the field, its mast is six camo net poles. Four guy ropes at the third pole on a stay plate, and two ropes opposing the dipole radiators at the 22′ feedpoint. It can withstand some real good winds.

    This antenna takes me about half an hour to set up by myself, I work slow. With a helper, it would set up much quicker. I use it on 75, 40, and 20m sometimes. Got an on-time, on-freq shot from elk camp on 20m to a bud about 800 miles away a couple years back on 20m, armchair copy on both ends.

    I’ve used your mentioned V-sloper to regularly talk on 20m to a bud 650m away. Set up via road atlas for azimuth. Legs are set out at a 90 degree arc with target in the middle of the arc. One time on 20m I reduced power to 5w voice and it was still good copy for the target station. This is a seasonal antenna, and summer finds it hard to mow around all the ropes and stakes.

    My house antenna is a droopy dipole cut by the number for 3.880. It gives 1:1 swr for a long ways on either side of that freq without a tuner. Feedpoint is about 39′, ends are about 15′ above ground. It does real well barefoot in a 300m radius, people don’t ask anymore if I’m running power. It does well as the band goes long, and does well in bad band conditions. I liken this antenna’s effect to sending a signal pretty much straight up, and getting Thor’s hammer coming down within the radius area. Works good with a station ten miles away, also, confirmed.

    There’s another .mil NVIS antenna, a tri-band. Can’t remember its nomenclature, 2245 maybe. It is three dipoles from one feedpoint: 75m wire strung over 40m wire on one axis, and the 60m dipole stabilizing the others at a right angle. Built one, it worked fine. 60m is an often overlooked band, you only get five freqs but they may be quiet depending on where you live.

  6. PRCD

    THis was the first I’ve heard of NVIS. I think it would be the only way (in this band) to practically beat DF receivers that use multiple receive arrays and triangulation. You would still have to communicate from fairly far away to whoever was receiving it. Triangulation takes only milliseconds and you can be sure OPFOR would use it in an area they suspected enemies to be operating.

    1. Check out my article on NVIS I wrote a few months ago on this blog.

      HF is for beyond line of sight. This is long distance.

      And no, you won’t stop dedicated DF assets. But through directional antennas for both the transmitter and intended receiver, it makes life a lot harder for OPFOR.

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